bugfix and dashboard improvement

README.md

@@ -17,10 +17,10 @@ HTTP API.
 |---------|-------------|
 | **Leader gate** | Bash `flock` loop in `docker/leader-election.sh` only `exec`s supervisord on the winner. The Go binary therefore only ever runs as leader. |
 | **Redis owner** | Supervisord starts Redis with AOF + RDB persistence inside the container; meta-core connects to it on localhost. |
-| **HTTP API** | Typed REST surface (gorilla/mux) for metadata, KV browsing, snapshots, schema inference, mounts, watchers, services, and file access by CID. |
+| **HTTP API** | Typed REST surface (gorilla/mux) for metadata, KV browsing, snapshots, schema inference, mounts, watchers, neighbours, and file access by CID. |
 | **SSE event streams** | `/api/events/files` and `/api/events/meta` mirror the underlying Redis Streams so external services never speak Redis. |
 | **WebDAV server** | `/webdav/*` exposes the `/files` volume (read+write) for cross-service file access. nginx in front of meta-core handles caching. |
-| **Service discovery** | File-based registry under `/meta-core/services/*.json` with heartbeat + dead-service cleanup. |
+| **Service discovery** | meta-discovery v1: UDP multicast announce/listen on `239.255.77.1:9399`, neighbours served at `/neighbors`. The file-based registry under `/meta-core/services/*.json` it replaced is gone. |
 | **File watcher / scanner** | Recursive scan + MidHash256 computation; emits events on `file:events`. |
 | **Mount management** | rclone-only mount manager (SMB rendered into `:smb:`, plus pre-defined remotes). Read-only by construction. |
 | **UUID-rooted storage** | Roots are UUIDv7 (Crockford Base32, ULID layout); CIDs are reverse-index aliases. Schema-version sentinel refuses to boot against stale data. |
@@ -167,12 +167,43 @@ GET  /health           # storage + role
 GET  /status           # version, uptime, etc.
 GET  /leader           # current leader info (hostname, PID, timestamps)
 GET  /urls             # baseUrl, apiUrl, webdavUrl, webdavUrlInternal (redisUrl is intentionally empty)
-GET  /services         # registered services + heartbeats
+GET  /neighbors        # neighbours heard over UDP (meta-discovery v1)
-GET  /api/services     # alias for /services
+GET  /api/neighbors    # same, under /api
-GET  /services/{name}  # one service
+GET  /api/stats        # dashboard counters (see below)
-GET  /services/cleanup/stats
 ```
 
+`/services`, `/api/services`, `/services/{name}` and `/services/cleanup/stats`
+are **gone** — the registration-and-heartbeat registry they served was replaced
+by meta-discovery v1 (`/neighbors`). nginx answers an unknown non-`/api` path
+with the dashboard's `index.html`, so a stale caller gets `200 text/html` rather
+than a 404; that is what made the dashboard fail with
+`SyntaxError: Unexpected token '<'` until 1.0.21.
+
+#### `GET /api/stats`
+
+Every headline counter in one request, split by cost:
+
+```jsonc
+{
+  "records": 88709,        // SCARD file:__index__ — metadata roots, file or not
+  "redisKeys": 3115447,    // DBSIZE — the flat per-field keys dominate
+  "redisMemory": "588.74M",
+  "identities": 3,         // signing accounts on disk
+  "files": { "count": 4864, "totalSize": 64587914424 },  // null until first sweep
+  "udlUsers": 5,           // accounts holding User Data Layer records
+  "sweptAt": 1789402401970,
+  "sweeping": false
+}
+```
+
+The first four are O(1) commands and are live on every call. `files` and
+`udlUsers` need a keyspace walk (~0.5s and ~3s respectively on an 88k-record
+box), so they are served from a single-flight cache refreshed in the background
+with a 60s TTL — the walk is **never** on the request path, because the
+dashboard polls and ten open tabs must not cost ten Redis walks. Prefer this
+over `/api/kv/info`, which does one `GET` per root (6s+) and sums `sizeByte`
+across records that share a file.
+
 ### Metadata — primary surface
 
 These are the routes other services use. `{hash}` may be a UUID root or
@@ -209,6 +240,7 @@ the `/file/{cid}` reverse-lookup path.)
 
 ```bash
 GET    /api/metadata/hash-ids
+GET    /api/files/tuples
 GET    /api/metadata/list
 POST   /api/metadata/search
 POST   /api/metadata/batch
@@ -287,6 +319,10 @@ return a deprecation pointer at the `/api/watchers/*` routes
 
 ```bash
 POST   /api/admin/migrate-dual-roots  # reunify stranded midhash-rooted entries
+POST   /api/admin/sweep-literature-echoes[?apply=true]
+       # strip query echoes off literature cards: anilistid on site cards,
+       # workcid/chapterNumber/volumeNumber/chapterStart/chapterEnd on any card.
+       # Dry-run unless apply=true; returns {dryRun, planned, fixed, byKey}
 GET/PUT/DELETE /webdav/...            # mounted on /files
 ```
 

cmd/meta-core/main.go

@@ -10,8 +10,8 @@ import (
 
 	"github.com/metazla/meta-core/internal/api"
 	"github.com/metazla/meta-core/internal/config"
-	"github.com/metazla/meta-core/internal/discovery"
 	"github.com/metazla/meta-core/internal/leader"
+	"github.com/metazla/meta-core/internal/meshdisco"
 	"github.com/metazla/meta-core/internal/storage"
 )
 
@@ -60,20 +60,47 @@ func main() {
 	}
 	log.Printf("[meta-core] Redis schema version OK (v%d)", storage.SchemaVersion)
 
-	// Create and start service discovery
+	// UDP service discovery (meta-discovery v1). Runs alongside the file
-	disc := discovery.NewService(cfg)
+	// registry above for now — nothing consumes the wire yet, so this cannot
-	if err := disc.Start(); err != nil {
+	// regress the existing path. The announce payload is rebuilt from
-		log.Fatalf("[meta-core] Failed to start service discovery: %v", err)
+	// leaderProvider on every tick, which is what keeps it and GET /urls from
+	// drifting apart.
+	var mesh *meshdisco.Node
+	if cfg.EnableUDPDiscovery {
+		hostname, _ := os.Hostname()
+		mesh = meshdisco.New(meshdisco.Config{
+			Name:     cfg.ServiceName,
+			Instance: hostname,
+			Role:     meshdisco.RoleCore,
+			Version:  Version,
+			Group:    cfg.DiscoveryGroup,
+			Port:     cfg.DiscoveryPort,
+			Interval: time.Duration(cfg.DiscoveryIntervalMS) * time.Millisecond,
+			Payload: func() (string, string, *meshdisco.URLs) {
+				info := leaderProvider.LeaderInfo()
+				if info == nil {
+					return "", "starting", nil
 				}
-
+				return coreBaseURL(cfg), "running", &meshdisco.URLs{
-	// Create and start dead service cleaner
+					Hostname:          info.Hostname,
-	cleaner := discovery.NewCleaner(cfg)
+					BaseUrl:           info.BaseUrl,
-	if err := cleaner.Start(); err != nil {
+					ApiUrl:            info.ApiUrl,
-		log.Printf("[meta-core] Warning: failed to start service cleaner: %v", err)
+					WebdavUrl:         info.WebdavUrl,
+					WebdavUrlInternal: info.WebdavUrlInternal,
+				}
+			},
+		})
+		if err := mesh.Start(); err != nil {
+			log.Printf("[meta-core] Warning: UDP discovery disabled: %v", err)
+			mesh = nil
+		}
+	} else {
+		log.Println("[meta-core] UDP discovery disabled by ENABLE_UDP_DISCOVERY")
 	}
 
 	// Create and start API server
-	apiServer := api.NewServer(cfg, leaderProvider, disc, cleaner, storageClient)
+	apiServer := api.NewServer(cfg, leaderProvider, storageClient)
+	apiServer.SetMeshNode(mesh)
 	if err := apiServer.Start(); err != nil {
 		log.Fatalf("[meta-core] Failed to start API server: %v", err)
 	}
@@ -90,12 +117,10 @@ func main() {
 		log.Printf("[meta-core] Error stopping API server: %v", err)
 	}
 
-	if err := cleaner.Stop(); err != nil {
+	if mesh != nil {
-		log.Printf("[meta-core] Error stopping service cleaner: %v", err)
+		if err := mesh.Stop(); err != nil {
+			log.Printf("[meta-core] Error stopping UDP discovery: %v", err)
 		}
-
-	if err := disc.Stop(); err != nil {
-		log.Printf("[meta-core] Error stopping service discovery: %v", err)
 	}
 
 	if err := storageClient.Close(); err != nil {
@@ -112,3 +137,17 @@ func waitForShutdown() {
 	<-sigChan
 }
 
+// coreBaseURL is the browser-facing URL announced for the nav menu. It keeps
+// the three-way fallback the file registry used (discovery/service.go):
+// META_CORE_PUBLIC_URL wins (the reachable URL when there is no Caddy
+// perimeter, e.g. a debug-direct port), then BASE_URL (the Caddy URL), then
+// the container IP.
+func coreBaseURL(cfg *config.Config) string {
+	if cfg.PublicURL != "" {
+		return cfg.PublicURL
+	}
+	if cfg.BaseURL != "" {
+		return cfg.BaseURL
+	}
+	return fmt.Sprintf("http://%s:%d", meshdisco.LocalIPv4(), cfg.APIPort)
+}

dashboard/dist/index.html

@@ -21,7 +21,7 @@
         min-height: 100vh;
       }
     </style>
-    <script type="module" crossorigin src="/assets/index-Cbd1uH5A.js"></script>
+    <script type="module" crossorigin src="/assets/index-Bgo6moAc.js"></script>
     <link rel="stylesheet" crossorigin href="/assets/index-DtR_2V4s.css">
   </head>
   <body>

dashboard/package-lock.json

@@ -8,6 +8,7 @@
       "name": "@meta-core/dashboard",
       "version": "1.0.0",
       "dependencies": {
+        "@noble/secp256k1": "^3.1.0",
         "iso-639-3": "^3.0.1",
         "react": "^18.2.0",
         "react-dom": "^18.2.0",
@@ -744,6 +745,15 @@
         "@jridgewell/sourcemap-codec": "^1.4.14"
       }
     },
+    "node_modules/@noble/secp256k1": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/@noble/secp256k1/-/secp256k1-3.1.0.tgz",
+      "integrity": "sha512-+F7iS7tUMaNGXcc9X3PjmjvuQnXEuSjCRNzVVA2xAcKXgCaP0dHYz4SFyt4FKNHef7sOP//xihowcySSS7PK9g==",
+      "license": "MIT",
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
     "node_modules/@remix-run/router": {
       "version": "1.23.2",
       "resolved": "https://registry.npmjs.org/@remix-run/router/-/router-1.23.2.tgz",

dashboard/package.json

@@ -9,10 +9,11 @@
     "preview": "vite preview"
   },
   "dependencies": {
+    "@noble/secp256k1": "^3.1.0",
+    "iso-639-3": "^3.0.1",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
-    "react-router-dom": "^6.20.0",
+    "react-router-dom": "^6.20.0"
-    "iso-639-3": "^3.0.1"
   },
   "devDependencies": {
     "@types/react": "^18.2.38",

dashboard/src/components/ServiceNav.tsx

@@ -1,155 +1,53 @@
-import { useState, useEffect } from 'react';
+import { useEffect } from 'react';
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore -- plain ES module, no .d.ts; imported for its side effect
+// of defining the custom element.
+import '../meta-service-menu.js';
 
-interface ServiceInfo {
+/**
-  name: string;
+ * ServiceNav — the neighbouring meta-* services, as a burger menu.
-  hostname: string;
+ *
-  baseUrl: string;
+ * Since meta-discovery v1 this is a thin wrapper around <meta-service-menu>,
-  status: string;
+ * a framework-free custom element shared by every meta-* UI (see
-  lastHeartbeat: string;
+ * scripts/check-mirrors.sh). The old implementation was ~165 lines of React
-}
+ * that existed in four near-identical copies and polled meta-core's
+ * /api/services; the element polls this service's own /api/neighbors instead,
+ * so the nav still renders when meta-core is down.
+ *
+ * The element lives in shadow DOM and cannot see this app's CSS variables, so
+ * the four --mm-nav-* tokens below map our palette onto it.
+ */
 
-interface ServicesResponse {
+declare global {
-  services: ServiceInfo[];
+    // eslint-disable-next-line @typescript-eslint/no-namespace
-  current: string;
+    namespace JSX {
-}
+        interface IntrinsicElements {
-
+            'meta-service-menu': React.DetailedHTMLProps<
-const serviceIcons: Record<string, string> = {
+                React.HTMLAttributes<HTMLElement>,
-  'meta-core': '🗄️',
+                HTMLElement
-  'meta-sort': '📁',
+            > & { current?: string; endpoint?: string; label?: string };
-  'meta-fuse': '🗂️',
+        }
-  'meta-stremio': '🎬',
+    }
-  'meta-orbit': '🌐',
-  'default': '📦'
-};
-
-function formatServiceName(name: string): string {
-  return name.split('-').map(word =>
-    word.charAt(0).toUpperCase() + word.slice(1)
-  ).join(' ');
 }
 
 function ServiceNav() {
-  const [services, setServices] = useState<ServiceInfo[]>([]);
-  const [loading, setLoading] = useState(true);
-  const currentService = 'meta-core';
-
     useEffect(() => {
-    const fetchServices = async () => {
+        // Import above is for the side effect of defining the element; this
-      try {
+        // keeps bundlers from tree-shaking it away in production builds.
-        const response = await fetch('/services');
-        if (response.ok) {
-          const data: ServicesResponse = await response.json();
-          setServices(data.services || []);
-        }
-      } catch (error) {
-        console.error('Failed to fetch services:', error);
-      } finally {
-        setLoading(false);
-      }
-    };
-
-    fetchServices();
-    const interval = setInterval(fetchServices, 30000);
-    return () => clearInterval(interval);
     }, []);
 
-  if (loading) return null;
-
-  const sortedServices = [...services].sort((a, b) => a.name.localeCompare(b.name));
-
-  if (sortedServices.length === 0) return null;
-
     return (
-    <nav className="services-nav">
+        <>
-      <span className="services-nav-label">Services:</span>
+            <meta-service-menu current="meta-core" />
-      <div className="services-nav-items">
-        {sortedServices.map(service => {
-          const icon = serviceIcons[service.name] || serviceIcons.default;
-          const isActive = service.name === currentService;
-          return (
-            <a
-              key={service.name}
-              href={isActive ? '#' : service.baseUrl}
-              className={`service-link${isActive ? ' active' : ''}`}
-              onClick={(e) => {
-                e.preventDefault();
-                if (!isActive) {
-                  window.location.href = service.baseUrl;
-                }
-              }}
-            >
-              <span className="service-icon">{icon}</span>
-              <span>{formatServiceName(service.name)}</span>
-              <span className="service-status"></span>
-            </a>
-          );
-        })}
-      </div>
-
             <style>{`
-        .services-nav {
+                meta-service-menu {
-          display: flex;
+                    --mm-nav-fg: var(--text-primary, #e0e0e0);
-          align-items: center;
+                    --mm-nav-bg: var(--bg-tertiary, var(--bg-secondary, #1a1a2e));
-          gap: 0.5rem;
+                    --mm-nav-border: var(--border-color, rgba(255,255,255,0.14));
-        }
+                    --mm-nav-accent: var(--accent-primary, #4ecdc4);
-
-        .services-nav-label {
-          color: #888;
-          font-size: 0.8rem;
-          white-space: nowrap;
-        }
-
-        .services-nav-items {
-          display: flex;
-          gap: 0.35rem;
-        }
-
-        .service-link {
-          display: inline-flex;
-          align-items: center;
-          gap: 0.3rem;
-          padding: 0.35rem 0.6rem;
-          border-radius: 6px;
-          text-decoration: none;
-          font-size: 0.8rem;
-          font-weight: 500;
-          transition: all 0.2s;
-          color: #ccc;
-          background: #0f3460;
-          border: 1px solid #1a4a7a;
-        }
-
-        .service-link:hover {
-          background: #1a4a7a;
-          border-color: rgba(78, 205, 196, 0.5);
-          text-decoration: none;
-          color: #fff;
-        }
-
-        .service-link.active {
-          background: linear-gradient(135deg, rgba(78, 205, 196, 0.2), rgba(68, 160, 141, 0.2));
-          border-color: rgba(78, 205, 196, 0.5);
-          color: #fff;
-        }
-
-        .service-link .service-icon {
-          font-size: 0.9rem;
-        }
-
-        .service-link .service-status {
-          width: 5px;
-          height: 5px;
-          border-radius: 50%;
-          background: #4ecdc4;
-        }
-
-        @media (max-width: 800px) {
-          .services-nav-label {
-            display: none;
-          }
                 }
             `}</style>
-    </nav>
+        </>
     );
 }
 

dashboard/src/lib/api.ts

@@ -0,0 +1,28 @@
+// JSON fetch that fails with a sentence instead of a parser error.
+//
+// nginx serves the dashboard with `try_files $uri $uri/ /index.html`, so ANY
+// path it does not have a proxy rule for answers 200 text/html with the SPA
+// shell. A caller that does `res.ok && res.json()` on such a path gets
+// `SyntaxError: Unexpected token '<', "<!doctype "... is not valid JSON` and
+// no clue which request produced it — which is exactly how a route deleted
+// from the Go router (`/services`, removed in favour of /api/neighbors) sat
+// broken on the dashboard.
+//
+// So: check the content type, and name the URL in every error.
+
+export async function getJSON<T>(url: string, init?: RequestInit): Promise<T> {
+  const res = await fetch(url, init);
+  const ct = res.headers.get('content-type') || '';
+
+  if (!res.ok) {
+    throw new Error(`${url} → HTTP ${res.status}`);
+  }
+  if (!ct.includes('application/json')) {
+    // The SPA fallback is the overwhelmingly likely cause; say so.
+    throw new Error(
+      `${url} → ${res.status} ${ct || 'no content-type'} (not JSON — the route is ` +
+        `missing and nginx served the dashboard shell instead)`
+    );
+  }
+  return (await res.json()) as T;
+}

dashboard/src/lib/sign.ts

@@ -0,0 +1,127 @@
+// Client-side proof of possession for account operations.
+//
+// meta-core stores every private key in plaintext, so it can sign as anybody —
+// which means a signature it produced proves nothing about who asked. The only
+// signature that carries authority is one made where the key actually is, and
+// for a browser-driven admin console that is here. meta-core enforces the other
+// half by refusing to sign anything in the challenge domain
+// (identity.ChallengeDomain), so this path cannot be short-circuited.
+//
+// The secret key entered on this page is used for exactly one signature and is
+// never sent anywhere: `/api/identity/challenge` receives only the uid, and the
+// request that follows carries only the challenge and its signature.
+//
+// Same scheme, same curve and same encodings as meta-watch's sign-in
+// (packages/meta-watch/ui/js/auth.js) — deliberately, so one implementation on
+// the server verifies both.
+
+import * as secp from '@noble/secp256k1';
+
+export type IdentityAction = 'reveal' | 'delete';
+
+function hexToBytes(hex: string): Uint8Array | null {
+  let h = hex.trim();
+  if (h.startsWith('0x') || h.startsWith('0X')) h = h.slice(2);
+  if (h.length !== 64 || /[^0-9a-fA-F]/.test(h)) return null;
+  const out = new Uint8Array(32);
+  for (let i = 0; i < 32; i++) out[i] = parseInt(h.slice(i * 2, i * 2 + 2), 16);
+  return out;
+}
+
+function bytesToBase64(bytes: Uint8Array): string {
+  let s = '';
+  for (const b of bytes) s += String.fromCharCode(b);
+  return btoa(s);
+}
+
+const B58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
+
+/// base58btc, the multibase "z" alphabet. Spelled out rather than pulled in:
+/// the alternative is a second dependency for thirty lines of arithmetic.
+function base58Encode(bytes: Uint8Array): string {
+  const digits: number[] = [0];
+  for (const byte of bytes) {
+    let carry = byte;
+    for (let i = 0; i < digits.length; i++) {
+      carry += digits[i] << 8;
+      digits[i] = carry % 58;
+      carry = (carry / 58) | 0;
+    }
+    while (carry) {
+      digits.push(carry % 58);
+      carry = (carry / 58) | 0;
+    }
+  }
+  // Leading zero bytes encode as leading '1's rather than being dropped.
+  let out = '';
+  for (let i = 0; i < bytes.length && bytes[i] === 0; i++) out += B58[0];
+  for (let i = digits.length - 1; i >= 0; i--) out += B58[digits[i]];
+  return out;
+}
+
+/// The uid a secret key belongs to: "z" + base58btc(33-byte compressed pubkey).
+/// Derived locally so a mistyped or wrong-account key is caught before any
+/// request goes out. Mirrors `identityFromPrivKey` in meta-core's identity.go.
+export function uidFromSecretKey(secretKeyHex: string): string | null {
+  const raw = hexToBytes(secretKeyHex);
+  if (!raw) return null;
+  try {
+    return 'z' + base58Encode(secp.getPublicKey(raw, true));
+  } catch {
+    return null; // not a valid scalar
+  }
+}
+
+/// Whether this page can sign at all.
+///
+/// noble's signAsync takes its sha256 from crypto.subtle, which browsers expose
+/// only in a secure context. The dashboard behind Caddy is https and fine; the
+/// debug-direct port (18083) is plain http, where every signature would fail
+/// with a cryptic error unless we say so first.
+export function canSign(): boolean {
+  return Boolean(globalThis.crypto?.subtle);
+}
+
+export const INSECURE_CONTEXT_MESSAGE =
+  'This page cannot sign over a plain-http connection — browsers only expose the ' +
+  'needed crypto on https (or localhost). Reach the dashboard through Caddy ' +
+  '(https://metacore-dev.localhost:8083) rather than the debug-direct port.';
+
+/// Ask meta-core for a challenge, sign it locally, and hand back the proof.
+///
+/// Throws with a message fit to show the user. The caller passes the proof
+/// straight into the reveal/delete request body.
+export async function proveOwnership(
+  uid: string,
+  action: IdentityAction,
+  secretKeyHex: string
+): Promise<{ challenge: string; signature: string }> {
+  if (!canSign()) throw new Error(INSECURE_CONTEXT_MESSAGE);
+
+  const raw = hexToBytes(secretKeyHex);
+  if (!raw) {
+    throw new Error('That is not a valid secret key: expected 64 hex characters.');
+  }
+  const derived = uidFromSecretKey(secretKeyHex);
+  if (!derived) throw new Error('That is not a valid secp256k1 secret key.');
+  if (derived !== uid) {
+    // Caught here rather than by the server, so the message can say which
+    // account the key actually is — the useful half of the answer.
+    throw new Error(`That key belongs to a different account (${derived}), not this one.`);
+  }
+
+  const cRes = await fetch('/api/identity/challenge', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ uid, action }),
+  });
+  const cBody = await cRes.json().catch(() => ({}));
+  if (!cRes.ok || !cBody.challenge) {
+    throw new Error(cBody.message ?? `Could not start verification (HTTP ${cRes.status}).`);
+  }
+
+  // signAsync prehashes with sha256 and returns a 64-byte compact (r‖s)
+  // signature — noble v3 dropped DER. meta-core's identity.Verify accepts both.
+  const sig = await secp.signAsync(new TextEncoder().encode(cBody.challenge), raw);
+  return { challenge: cBody.challenge, signature: bytesToBase64(sig) };
+}

dashboard/src/meta-service-menu.js

@@ -0,0 +1,303 @@
+/**
+ * <meta-service-menu> — the neighbouring meta-* services, as a burger menu.
+ *
+ * Replaces the eight divergent "services bar" implementations (four copies of
+ * a React `ServiceNav.tsx`, two mirrored `services.js`, two bespoke inline
+ * ones) with a single framework-free custom element. It drops into the React
+ * dashboards as a plain tag — no React dependency — and into the vanilla UIs
+ * as an ES module.
+ *
+ * Data comes from the host service's own `GET /api/neighbors`, same-origin.
+ * Never cross-origin: the dev stack's self-signed certs and the OIDC redirects
+ * make a fetch to a neighbour a dead end. Links are plain navigations.
+ *
+ * ⚠ MIRRORED FILE. Byte-identical copies live in every meta-* UI tree; see
+ * `scripts/check-mirrors.sh`. Edit one → edit all.
+ *
+ * Shadow DOM is not optional here. The eight UIs use four incompatible token
+ * vocabularies, and two of them define *different colours under the same
+ * names* (`--bg-secondary` is #12121a in meta-sort, #16213e in meta-core,
+ * #161b22 in meta-dup). meta-search and meta-share are also the only
+ * light-mode-capable UIs, so a hardcoded dark palette would break them.
+ * The element therefore styles itself from four tokens with dark defaults:
+ *
+ *     --mm-nav-fg, --mm-nav-bg, --mm-nav-border, --mm-nav-accent
+ *
+ * Each host maps its own variables onto those, e.g.
+ *     meta-service-menu { --mm-nav-bg: var(--bg-secondary); }
+ *
+ * Attributes:
+ *   current   name of the host service, so it can be marked and not linked
+ *   endpoint  override the default "/api/neighbors"
+ *   label     button tooltip (default "Services")
+ *
+ * Property:
+ *   rewriteUrl  optional (name, url, neighbour) => url, for hosts that must
+ *               translate internal hostnames into browser-reachable ones
+ *               (meta-gateway does this for its dev/prod split).
+ */
+
+const ICONS = {
+  "meta-core": "⚙️",
+  "meta-sort": "📁",
+  "meta-fuse": "🗂️",
+  "meta-stremio": "🎬",
+  "meta-dup": "🔍",
+  "meta-search": "🔎",
+  "meta-share": "🔗",
+  "meta-gateway": "🌉",
+  "meta-watch": "📺",
+  "meta-listen": "🎧",
+  "meta-read": "📖",
+};
+const DEFAULT_ICON = "📦";
+const POLL_MS = 30000;
+
+function titleCase(name) {
+  return String(name || "")
+    .split("-")
+    .map((w) => w.charAt(0).toUpperCase() + w.slice(1))
+    .join(" ");
+}
+
+const TEMPLATE = `
+<style>
+  :host {
+    --_fg: var(--mm-nav-fg, #e8eaed);
+    --_bg: var(--mm-nav-bg, #1a1a2e);
+    --_border: var(--mm-nav-border, rgba(255, 255, 255, 0.14));
+    --_accent: var(--mm-nav-accent, #4ecdc4);
+    position: relative;
+    display: inline-block;
+    font-family: inherit;
+    font-size: 14px;
+    line-height: 1.4;
+  }
+  button.trigger {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    gap: 0.4rem;
+    width: 2.1rem;
+    height: 2.1rem;
+    padding: 0;
+    cursor: pointer;
+    color: var(--_fg);
+    background: transparent;
+    border: 1px solid var(--_border);
+    border-radius: 8px;
+    font: inherit;
+    transition: border-color 0.15s, background 0.15s;
+  }
+  button.trigger:hover { border-color: var(--_accent); }
+  button.trigger:focus-visible {
+    outline: 2px solid var(--_accent);
+    outline-offset: 2px;
+  }
+  button.trigger[aria-expanded="true"] { border-color: var(--_accent); }
+  .bars { display: block; width: 15px; }
+  .bars span {
+    display: block;
+    height: 2px;
+    margin: 3px 0;
+    border-radius: 2px;
+    background: currentColor;
+  }
+  .panel {
+    position: absolute;
+    top: calc(100% + 6px);
+    right: 0;
+    z-index: 1000;
+    min-width: 13rem;
+    max-height: 70vh;
+    overflow-y: auto;
+    padding: 0.3rem;
+    background: var(--_bg);
+    border: 1px solid var(--_border);
+    border-radius: 10px;
+    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
+  }
+  .panel[hidden] { display: none; }
+  a.item, .item {
+    display: flex;
+    align-items: center;
+    gap: 0.55rem;
+    padding: 0.45rem 0.6rem;
+    border-radius: 6px;
+    color: var(--_fg);
+    text-decoration: none;
+    white-space: nowrap;
+  }
+  a.item:hover { background: color-mix(in srgb, var(--_accent) 18%, transparent); }
+  .item.active { color: var(--_accent); font-weight: 600; cursor: default; }
+  .item.dead { opacity: 0.55; cursor: not-allowed; }
+  .icon { font-size: 1rem; line-height: 1; }
+  .dot {
+    width: 6px;
+    height: 6px;
+    margin-left: auto;
+    border-radius: 50%;
+    background: var(--_accent);
+  }
+  .empty {
+    padding: 0.6rem;
+    opacity: 0.7;
+    font-size: 0.85em;
+    white-space: nowrap;
+  }
+  /* Respect a host that opts out of motion. */
+  @media (prefers-reduced-motion: reduce) {
+    button.trigger { transition: none; }
+  }
+</style>
+<button class="trigger" type="button" aria-haspopup="menu" aria-expanded="false">
+  <span class="bars" aria-hidden="true"><span></span><span></span><span></span></span>
+</button>
+<div class="panel" role="menu" hidden></div>
+`;
+
+class MetaServiceMenu extends HTMLElement {
+  constructor() {
+    super();
+    this.attachShadow({ mode: "open" });
+    this.shadowRoot.innerHTML = TEMPLATE;
+    this._btn = this.shadowRoot.querySelector("button.trigger");
+    this._panel = this.shadowRoot.querySelector(".panel");
+    this._neighbors = [];
+    this._timer = null;
+    this._open = false;
+
+    this._onDocClick = (e) => {
+      if (!this._open) return;
+      if (e.composedPath().includes(this)) return;
+      this._setOpen(false);
+    };
+    this._onKey = (e) => {
+      if (e.key === "Escape" && this._open) {
+        this._setOpen(false);
+        this._btn.focus();
+      }
+    };
+  }
+
+  connectedCallback() {
+    this._btn.title = this.getAttribute("label") || "Services";
+    this._btn.setAttribute("aria-label", this._btn.title);
+    this._btn.addEventListener("click", () => this._setOpen(!this._open));
+    document.addEventListener("click", this._onDocClick);
+    document.addEventListener("keydown", this._onKey);
+
+    this.refresh();
+    this._timer = setInterval(() => this.refresh(), POLL_MS);
+  }
+
+  disconnectedCallback() {
+    if (this._timer) clearInterval(this._timer);
+    this._timer = null;
+    document.removeEventListener("click", this._onDocClick);
+    document.removeEventListener("keydown", this._onKey);
+  }
+
+  get endpoint() {
+    return this.getAttribute("endpoint") || "/api/neighbors";
+  }
+
+  get current() {
+    return this.getAttribute("current") || "";
+  }
+
+  async refresh() {
+    try {
+      const res = await fetch(this.endpoint, {
+        headers: { Accept: "application/json" },
+      });
+      if (!res.ok) throw new Error(String(res.status));
+      const data = await res.json();
+      // `services` is the legacy alias some backends still emit.
+      this._neighbors = data.neighbors || data.services || [];
+    } catch {
+      // Silent: the menu is navigation, not a health indicator. Keep whatever
+      // we last had rather than blanking the list on one failed poll.
+    }
+    this._render();
+  }
+
+  _setOpen(open) {
+    this._open = open;
+    this._panel.hidden = !open;
+    this._btn.setAttribute("aria-expanded", String(open));
+    if (open) this.refresh();
+  }
+
+  _render() {
+    const panel = this._panel;
+    panel.textContent = "";
+
+    const seen = new Set();
+    const rows = [];
+    for (const n of this._neighbors) {
+      const name = n.name || "";
+      if (!name || seen.has(name)) continue;
+      seen.add(name);
+      rows.push(n);
+    }
+    // Always show the host itself, even before its own echo comes back.
+    if (this.current && !seen.has(this.current)) {
+      rows.push({ name: this.current, baseUrl: "" });
+    }
+    rows.sort((a, b) => String(a.name).localeCompare(String(b.name)));
+
+    if (rows.length === 0) {
+      const empty = document.createElement("div");
+      empty.className = "empty";
+      empty.textContent = "No services found";
+      panel.appendChild(empty);
+      return;
+    }
+
+    for (const n of rows) {
+      const isActive = n.name === this.current;
+      let url = n.baseUrl || "";
+      if (typeof this.rewriteUrl === "function") {
+        try {
+          url = this.rewriteUrl(n.name, url, n) || "";
+        } catch {
+          /* a bad hook must not blank the menu */
+        }
+      }
+
+      // A neighbour with no reachable URL is shown but not linked — better
+      // than a link that goes nowhere.
+      const el = document.createElement(isActive || !url ? "span" : "a");
+      el.className =
+        "item" + (isActive ? " active" : "") + (!isActive && !url ? " dead" : "");
+      if (el.tagName === "A") {
+        el.href = url;
+        el.setAttribute("role", "menuitem");
+      }
+      if (!isActive && !url) el.title = "No reachable URL announced";
+
+      const icon = document.createElement("span");
+      icon.className = "icon";
+      icon.textContent = ICONS[n.name] || DEFAULT_ICON;
+
+      const label = document.createElement("span");
+      label.textContent = titleCase(n.name);
+
+      el.append(icon, label);
+      if (n.status === "running" || isActive) {
+        const dot = document.createElement("span");
+        dot.className = "dot";
+        dot.title = n.status || "running";
+        el.appendChild(dot);
+      }
+      panel.appendChild(el);
+    }
+  }
+}
+
+if (!customElements.get("meta-service-menu")) {
+  customElements.define("meta-service-menu", MetaServiceMenu);
+}
+
+export default MetaServiceMenu;

dashboard/src/pages/Dashboard.tsx

@@ -1,4 +1,5 @@
 import { useEffect, useState } from 'react';
+import { getJSON } from '../lib/api';
 
 interface HealthStatus {
   status: string;
@@ -6,6 +7,22 @@ interface HealthStatus {
   timestamp: string;
 }
 
+interface FileStats {
+  count: number;
+  totalSize: number;
+}
+
+interface Stats {
+  records: number;
+  redisKeys: number;
+  redisMemory: string;
+  identities: number;
+  files: FileStats | null;
+  udlUsers: number | null;
+  sweptAt: number;
+  sweeping: boolean;
+}
+
 interface WatcherStatus {
   id: string;
   path: string;
@@ -22,13 +39,6 @@ interface WatchersResponse {
   count: number;
 }
 
-interface ServiceInfo {
-  name: string;
-  api: string;
-  capabilities: string[];
-  timestamp: number;
-}
-
 const cardStyle: React.CSSProperties = {
   background: '#16213e',
   borderRadius: '8px',
@@ -38,53 +48,110 @@ const cardStyle: React.CSSProperties = {
 
 const gridStyle: React.CSSProperties = {
   display: 'grid',
-  gridTemplateColumns: 'repeat(auto-fit, minmax(300px, 1fr))',
+  // 200px, not 220: five tiles must fit one row inside the 1200px container
+  // (1136 content - 4x16 gap = 1072 / 5 = 214 each) before wrapping.
+  gridTemplateColumns: 'repeat(auto-fit, minmax(200px, 1fr))',
   gap: '1rem',
+  marginBottom: '1rem',
 };
 
 const statStyle: React.CSSProperties = {
   fontSize: '2rem',
   fontWeight: 'bold',
   color: '#4ade80',
+  lineHeight: 1.2,
 };
 
+const labelStyle: React.CSSProperties = {
+  marginBottom: '0.75rem',
+  color: '#888',
+  fontSize: '0.85rem',
+  textTransform: 'uppercase',
+  letterSpacing: '0.04em',
+};
+
+const noteStyle: React.CSSProperties = {
+  color: '#6b7a99',
+  fontSize: '0.8rem',
+  marginTop: '0.4rem',
+};
+
+const numberFmt = new Intl.NumberFormat();
+
+function formatCount(n: number | null | undefined): string {
+  return n === null || n === undefined ? '—' : numberFmt.format(n);
+}
+
+// Binary units: this counts bytes on disk, and every other tool the operator
+// compares against (du, docker, the mount page) reports GiB.
+function formatBytes(bytes: number | null | undefined): string {
+  if (bytes === null || bytes === undefined) return '—';
+  const units = ['B', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB'];
+  let value = bytes;
+  let unit = 0;
+  while (value >= 1024 && unit < units.length - 1) {
+    value /= 1024;
+    unit++;
+  }
+  return `${value.toFixed(value >= 100 || unit === 0 ? 0 : 1)} ${units[unit]}`;
+}
+
+function Tile({
+  label,
+  value,
+  note,
+  pending,
+}: {
+  label: string;
+  value: string;
+  note?: string;
+  pending?: boolean;
+}) {
+  return (
+    <div style={cardStyle}>
+      <div style={labelStyle}>{label}</div>
+      <div style={{ ...statStyle, color: pending ? '#6b7a99' : statStyle.color }}>
+        {value}
+      </div>
+      {note && <div style={noteStyle}>{note}</div>}
+    </div>
+  );
+}
+
 export default function Dashboard() {
   const [health, setHealth] = useState<HealthStatus | null>(null);
+  const [stats, setStats] = useState<Stats | null>(null);
   const [watchersData, setWatchersData] = useState<WatchersResponse | null>(null);
-  const [services, setServices] = useState<ServiceInfo[]>([]);
   const [error, setError] = useState<string | null>(null);
 
   useEffect(() => {
+    let cancelled = false;
+
     const fetchData = async () => {
-      try {
+      // Settled, not all: one dead endpoint must not blank every tile.
-        // Fetch health
+      const [healthRes, statsRes, watchersRes] = await Promise.allSettled([
-        const healthRes = await fetch('/health');
+        getJSON<HealthStatus>('/health'),
-        if (healthRes.ok) {
+        getJSON<Stats>('/api/stats'),
-          setHealth(await healthRes.json());
+        getJSON<WatchersResponse>('/api/watchers'),
-        }
+      ]);
+      if (cancelled) return;
 
-        // Fetch watchers status
+      if (healthRes.status === 'fulfilled') setHealth(healthRes.value);
-        const watchersRes = await fetch('/api/watchers');
+      if (statsRes.status === 'fulfilled') setStats(statsRes.value);
-        if (watchersRes.ok) {
+      if (watchersRes.status === 'fulfilled') setWatchersData(watchersRes.value);
-          setWatchersData(await watchersRes.json());
-        }
 
-        // Fetch services
+      const failures = [healthRes, statsRes, watchersRes]
-        const servicesRes = await fetch('/services');
+        .filter((r): r is PromiseRejectedResult => r.status === 'rejected')
-        if (servicesRes.ok) {
+        .map((r) => String(r.reason?.message ?? r.reason));
-          const data = await servicesRes.json();
+      setError(failures.length ? failures.join(' · ') : null);
-          setServices(data.services || []);
-        }
-
-        setError(null);
-      } catch (err) {
-        setError(String(err));
-      }
     };
 
     fetchData();
     const interval = setInterval(fetchData, 5000);
-    return () => clearInterval(interval);
+    return () => {
+      cancelled = true;
+      clearInterval(interval);
+    };
   }, []);
 
   const handleTriggerScan = async () => {
@@ -95,49 +162,102 @@ export default function Dashboard() {
     }
   };
 
-  // Aggregate watcher stats
+  const isScanning = watchersData?.watchers.some((w) => w.isScanning) || false;
-  const totalFiles = watchersData?.watchers.reduce((sum, w) => sum + w.fileCount, 0) || 0;
+  const activeWatchers = watchersData?.watchers.filter((w) => w.active).length || 0;
-  const isScanning = watchersData?.watchers.some(w => w.isScanning) || false;
+  const lastScan =
-  const activeWatchers = watchersData?.watchers.filter(w => w.active).length || 0;
+    watchersData?.watchers.reduce((max, w) => Math.max(max, w.lastScan || 0), 0) || 0;
-  const lastScan = watchersData?.watchers.reduce((max, w) => Math.max(max, w.lastScan || 0), 0) || 0;
+
+  // Records we hold metadata for but have no local file: gateway/cid-rooted
+  // entries, plus anything whose file went away. The interesting number on a
+  // client box, where it should be most of them.
+  const fileless =
+    stats && stats.files ? Math.max(0, stats.records - stats.files.count) : null;
+
+  const sweepPending = !!stats && !stats.files;
+  const sweptNote = (() => {
+    if (!stats) return undefined;
+    if (sweepPending) return stats.sweeping ? 'scanning…' : 'not scanned yet';
+    if (stats.sweeping) return 'refreshing…';
+    if (stats.sweptAt) return `as of ${new Date(stats.sweptAt).toLocaleTimeString()}`;
+    return undefined;
+  })();
 
   return (
-    <div style={{ padding: '2rem', maxWidth: '1200px', margin: '0 auto' }}>
+    <div style={{ padding: '2rem', maxWidth: '1200px', margin: '0 auto', overflowY: 'auto', height: '100%' }}>
       <h1 style={{ marginBottom: '2rem' }}>meta-core Dashboard</h1>
 
       {error && (
         <div style={{ ...cardStyle, background: '#4a1a1a', color: '#f87171' }}>
-          Error: {error}
+          {error}
         </div>
       )}
 
       <div style={gridStyle}>
-        {/* Health Card */}
+        <Tile
+          label="Files discovered"
+          value={formatCount(stats?.files?.count)}
+          note={sweptNote}
+          pending={sweepPending}
+        />
+        <Tile
+          label="Library size"
+          value={formatBytes(stats?.files?.totalSize)}
+          note={sweptNote}
+          pending={sweepPending}
+        />
+        <Tile
+          label="Metadata entries"
+          value={formatCount(stats?.records)}
+          note={
+            fileless === null
+              ? 'records in the index'
+              : `${formatCount(fileless)} with no local file`
+          }
+        />
+        <Tile
+          label="Redis keys"
+          value={formatCount(stats?.redisKeys)}
+          note={stats?.redisMemory ? `${stats.redisMemory} in use` : undefined}
+        />
+        <Tile
+          label="Identities"
+          value={formatCount(stats?.identities)}
+          note={
+            stats?.udlUsers !== null && stats?.udlUsers !== undefined
+              ? `${formatCount(stats.udlUsers)} with user data`
+              : 'signing accounts'
+          }
+        />
+      </div>
+
+      <div style={{ ...gridStyle, gridTemplateColumns: 'repeat(auto-fit, minmax(300px, 1fr))' }}>
         <div style={cardStyle}>
-          <h3 style={{ marginBottom: '1rem', color: '#888' }}>Service Health</h3>
+          <div style={labelStyle}>Service health</div>
           {health ? (
             <>
               <div style={statStyle}>
                 {health.status === 'ok' ? 'Healthy' : health.status}
               </div>
-              <p>Redis: {health.redis ? 'Connected' : 'Disconnected'}</p>
+              <p style={noteStyle}>
+                Redis: {health.redis ? 'Connected' : 'Disconnected'}
+              </p>
             </>
           ) : (
-            <p>Loading...</p>
+            <p style={noteStyle}>Loading…</p>
           )}
         </div>
 
-        {/* Watchers Status Card */}
         <div style={cardStyle}>
-          <h3 style={{ marginBottom: '1rem', color: '#888' }}>File Watchers</h3>
+          <div style={labelStyle}>File watchers</div>
           {watchersData ? (
             <>
-              <div style={statStyle}>{totalFiles}</div>
+              <div style={statStyle}>
-              <p>Files discovered</p>
+                {activeWatchers} / {watchersData.count}
-              <p>Watchers: {activeWatchers} active / {watchersData.count} total</p>
+              </div>
-              <p>Status: {isScanning ? 'Scanning...' : 'Idle'}</p>
+              <p style={noteStyle}>active watchers</p>
+              <p style={noteStyle}>Status: {isScanning ? 'Scanning…' : 'Idle'}</p>
               {lastScan > 0 && (
-                <p>Last scan: {new Date(lastScan).toLocaleString()}</p>
+                <p style={noteStyle}>Last scan: {new Date(lastScan).toLocaleString()}</p>
               )}
               <button
                 onClick={handleTriggerScan}
@@ -155,27 +275,7 @@ export default function Dashboard() {
               </button>
             </>
           ) : (
-            <p>Loading...</p>
+            <p style={noteStyle}>Loading…</p>
-          )}
-        </div>
-
-        {/* Services Card */}
-        <div style={cardStyle}>
-          <h3 style={{ marginBottom: '1rem', color: '#888' }}>Connected Services</h3>
-          <div style={statStyle}>{services.length}</div>
-          <p>Services registered</p>
-          {services.length > 0 && (
-            <ul style={{ marginTop: '1rem', paddingLeft: '1.5rem' }}>
-              {services.map((svc) => (
-                <li key={svc.name} style={{ marginBottom: '0.5rem' }}>
-                  <strong>{svc.name}</strong>
-                  <br />
-                  <span style={{ color: '#888', fontSize: '0.9rem' }}>
-                    {svc.capabilities?.join(', ') || 'No capabilities'}
-                  </span>
-                </li>
-              ))}
-            </ul>
           )}
         </div>
       </div>

dashboard/src/pages/Identity.tsx

@@ -1,5 +1,13 @@
 import { useEffect, useRef, useState } from 'react';
 
+import {
+  INSECURE_CONTEXT_MESSAGE,
+  canSign,
+  proveOwnership,
+  uidFromSecretKey,
+  type IdentityAction,
+} from '../lib/sign';
+
 // Admin console for meta-core's account keystore.
 //
 // meta-core stores one secp256k1 keypair per file under
@@ -10,6 +18,13 @@ import { useEffect, useRef, useState } from 'react';
 // The private key is returned by exactly two calls: POST /api/identity/generate
 // (once, at creation) and POST /api/identity/reveal (on demand, for an account
 // that already exists). Both land in the same exclusive SecretKeyPanel.
+//
+// Reveal and remove both require the account's own secret key, entered here and
+// used to sign a one-shot challenge locally — the key itself is never sent. So
+// this page can enumerate and create, but it holds no authority over an
+// existing account that its operator does not already have the key for. There
+// is deliberately no admin override: on this node the private key *is* the
+// account.
 
 interface Account {
   uid: string;
@@ -17,6 +32,14 @@ interface Account {
   createdAt: number;
 }
 
+// What one account holds in the User Data Layer. Absent from
+// /api/udl/users/stats means zero, not unknown.
+interface Stats {
+  records: number;
+  cids: number;
+  keys: number;
+}
+
 // A secret on screen. Carries no createdAt: /api/identity/reveal answers with
 // {uid, curve, privateKeyHex} only.
 interface SecretKeyView {
@@ -32,6 +55,14 @@ interface Pending {
   kind: 'remove' | 'reveal';
 }
 
+// Both confirmable operations map to a server-side action name, and the
+// challenge is bound to it: a challenge minted to reveal a key cannot delete
+// the account. Keeping the mapping in one place stops the two drifting.
+const ACTION_FOR: Record<Pending['kind'], IdentityAction> = {
+  reveal: 'reveal',
+  remove: 'delete',
+};
+
 // meta-watch's sentinel cell for profile records: display name and avatar are
 // about the *user*, not a content file, so they live at (uid, "self", ...).
 // meta-core stores them opaquely and knows nothing of the convention.
@@ -173,6 +204,95 @@ async function fetchDisplayName(uid: string): Promise<string | null> {
   }
 }
 
+// How much each account holds. One call for the whole page, not one per row:
+// meta-core answers it from a keyspace SCAN (there is no per-user cid index),
+// so per-row calls would walk the keyspace once per account.
+//
+// Never throws, for the same reason fetchDisplayName does not: the counts are
+// context on top of the uid, and the list must render identically when Redis is
+// down — accounts are file-backed, their data is not.
+//
+// Returns null on failure rather than an empty map. The difference is
+// load-bearing: an empty map renders as "no stored data" against every account,
+// which inside a delete confirmation is a false statement about what is at
+// stake. Unknown has to look like unknown.
+async function fetchStats(): Promise<Record<string, Stats> | null> {
+  try {
+    const res = await fetch('/api/udl/users/stats');
+    if (!res.ok) return null;
+    const data = (await res.json()) as { users?: Record<string, Stats> };
+    return data.users ?? {};
+  } catch {
+    return null;
+  }
+}
+
+// The secret-key box shared by the reveal and remove confirmations.
+//
+// Separate from the surrounding panel so both operations ask the same way, and
+// so the key lives in this component's state rather than the page's — it is
+// discarded with the panel instead of lingering in a parent that outlives it.
+function SecretKeyConfirm({
+  label,
+  actionLabel,
+  busy,
+  onConfirm,
+  onCancel,
+}: {
+  label: string;
+  actionLabel: string;
+  busy: boolean;
+  onConfirm: (secretKeyHex: string) => void;
+  onCancel: () => void;
+}) {
+  const [secret, setSecret] = useState('');
+  const signable = canSign();
+  // Derived locally, purely to tell the operator they have the wrong key before
+  // they hit the button. The server would refuse either way.
+  const derived = secret.trim() ? uidFromSecretKey(secret) : null;
+  const mismatch = Boolean(secret.trim() && derived && derived !== label);
+
+  return (
+    <form
+      onSubmit={(e) => {
+        e.preventDefault();
+        onConfirm(secret.trim());
+      }}
+    >
+      <p style={{ color: '#fecaca', margin: '0 0 0.5rem' }}>
+        Paste this account's secret key to prove it is yours. It is used to sign a one-time
+        challenge <em>in this browser</em> and is never sent to the server.
+      </p>
+      {!signable && <p style={errorTextStyle}>{INSECURE_CONTEXT_MESSAGE}</p>}
+      <input
+        style={inputStyle}
+        type="password"
+        autoComplete="off"
+        placeholder="64 hex characters"
+        value={secret}
+        onChange={(e) => setSecret(e.target.value)}
+        disabled={busy || !signable}
+        autoFocus
+      />
+      {mismatch && (
+        <p style={{ ...errorTextStyle, marginTop: 0 }}>
+          That key belongs to a different account ({derived}).
+        </p>
+      )}
+      <button
+        type="submit"
+        style={dangerButtonStyle}
+        disabled={busy || !signable || !secret.trim() || mismatch}
+      >
+        {busy ? 'Verifying…' : actionLabel}
+      </button>
+      <button type="button" style={buttonStyle} onClick={onCancel} disabled={busy}>
+        Cancel
+      </button>
+    </form>
+  );
+}
+
 // The one place a private key is ever displayed. Rendered exclusively (the
 // account list is hidden while it is open) so the "save it now" contract of a
 // freshly generated key is not competing with anything, and so the hardcoded
@@ -351,6 +471,7 @@ function NewAccountPanel({
 function AccountCard({
   account,
   name,
+  stats,
   busy,
   disabled,
   pending,
@@ -362,18 +483,24 @@ function AccountCard({
 }: {
   account: Account;
   name?: string;
+  // undefined means "counted, and it holds nothing"; null means "could not be
+  // counted". The two must not read the same on a confirmation screen.
+  stats?: Stats | null;
   busy: boolean;
   disabled: boolean;
   pending: Pending | null;
   error: string | null;
   onAsk: (p: Pending) => void;
   onCancel: () => void;
-  onReveal: (uid: string) => void;
+  onReveal: (uid: string, secretKeyHex: string) => void;
-  onRemove: (uid: string) => void;
+  onRemove: (uid: string, secretKeyHex: string) => void;
 }) {
   const [copied, setCopied] = useState(false);
   const uidBoxId = `mm-uid-${account.uid}`;
   const label = name ?? account.uid;
+  const counted = stats !== null;
+  const records = stats?.records ?? 0;
+  const titles = stats?.cids ?? 0;
 
   const copyUid = async () => {
     await copyToClipboard(account.uid, uidBoxId);
@@ -394,6 +521,16 @@ function AccountCard({
           <p style={{ color: '#888', margin: '0.75rem 0 0', fontSize: '0.85rem' }}>
             Curve: {account.curve} · Created: {formatCreatedAt(account.createdAt)}
           </p>
+          <p style={{ color: '#888', margin: '0.25rem 0 0', fontSize: '0.85rem' }}>
+            {/* An account that has never been used legitimately holds nothing, so
+                zero is a real answer — but only once the count actually ran. */}
+            {!counted
+              ? 'Stored data: could not be counted (storage unavailable)'
+              : records === 0
+                ? 'No stored data'
+                : `${records.toLocaleString()} stored ${records === 1 ? 'record' : 'records'}` +
+                  ` across ${titles.toLocaleString()} ${titles === 1 ? 'title' : 'titles'}`}
+          </p>
         </div>
         <div style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem', flexShrink: 0 }}>
           <button style={{ ...buttonStyle, marginRight: 0 }} onClick={copyUid} disabled={disabled}>
@@ -425,15 +562,17 @@ function AccountCard({
           </p>
           <p style={{ color: '#fecaca', marginTop: 0 }}>
             The key <em>is</em> the account. Anyone who copies it can sign records as this uid on
-            any machine, forever — there is no way to revoke or rotate it afterwards. meta-core
+            any machine, forever — there is no way to revoke or rotate it afterwards. Because
-            will hand it over without asking who you are; see the note at the top of this page.
+            proving ownership already requires the key, this only confirms that the copy this node
+            holds matches yours.
           </p>
-          <button style={dangerButtonStyle} onClick={() => onReveal(account.uid)} disabled={busy}>
+          <SecretKeyConfirm
-            {busy ? 'Revealing…' : 'Yes, show the private key'}
+            label={account.uid}
-          </button>
+            actionLabel="Show the private key"
-          <button style={buttonStyle} onClick={onCancel} disabled={busy}>
+            busy={busy}
-            Cancel
+            onConfirm={(secret) => onReveal(account.uid, secret)}
-          </button>
+            onCancel={onCancel}
+          />
         </div>
       )}
 
@@ -454,21 +593,31 @@ function AccountCard({
               verifying on every peer that replicated them. Deleting a key is not a recall.
             </li>
             <li>
-              <strong>Its data stays, but goes read-only.</strong> The account's User Data Layer
+              <strong>Its data is destroyed, not orphaned.</strong>{' '}
-              cells — likes, ratings, watch progress — survive in Redis, and no newer version of
+              {!counted
-              any of them can ever be written.
+                ? 'This account\u2019s records could not be counted because storage is unavailable — ' +
+                  'so meta-core will refuse this delete rather than remove the key and strand them.'
+                : records === 0
+                  ? 'This account holds no User Data Layer records, so there is nothing to purge.'
+                  : `All ${records.toLocaleString()} User Data Layer ${
+                      records === 1 ? 'record' : 'records'
+                    } — likes, ratings, watch progress across ${titles.toLocaleString()} ${
+                      titles === 1 ? 'title' : 'titles'
+                    } — are permanently deleted from Redis, along with every index that names this uid.`}{' '}
+              This cannot be undone and there is no backup.
             </li>
             <li>
               <strong>This signs nobody out elsewhere.</strong> Any device that holds this key
               still holds it, and can import it back here at any time.
             </li>
           </ul>
-          <button style={dangerButtonStyle} onClick={() => onRemove(account.uid)} disabled={busy}>
+          <SecretKeyConfirm
-            {busy ? 'Removing…' : 'Yes, remove this account'}
+            label={account.uid}
-          </button>
+            actionLabel="Remove this account and all its data"
-          <button style={buttonStyle} onClick={onCancel} disabled={busy}>
+            busy={busy}
-            Cancel
+            onConfirm={(secret) => onRemove(account.uid, secret)}
-          </button>
+            onCancel={onCancel}
+          />
         </div>
       )}
     </div>
@@ -478,6 +627,8 @@ function AccountCard({
 export default function Identity() {
   const [accounts, setAccounts] = useState<Account[] | null>(null);
   const [names, setNames] = useState<Record<string, string>>({});
+  const [stats, setStats] = useState<Record<string, Stats> | null>({});
+  const [notice, setNotice] = useState<string | null>(null);
   const [loading, setLoading] = useState(true);
   const [fetchError, setFetchError] = useState<string | null>(null);
   const [secret, setSecret] = useState<SecretKeyView | null>(null);
@@ -508,30 +659,39 @@ export default function Identity() {
     setAccounts(list);
     setLoading(false);
 
-    const settled = await Promise.allSettled(list.map((a) => fetchDisplayName(a.uid)));
+    // Names and counts both come after the list is on screen, and neither can
+    // fail the page: a down Redis costs decoration, not the account list.
+    const [settled, counts] = await Promise.all([
+      Promise.allSettled(list.map((a) => fetchDisplayName(a.uid))),
+      fetchStats(),
+    ]);
     if (gen !== reqGen.current) return;
     const next: Record<string, string> = {};
     settled.forEach((r, i) => {
       if (r.status === 'fulfilled' && r.value) next[list[i].uid] = r.value;
     });
-    // Replace rather than merge, so a removed account's name goes with it.
+    // Replace rather than merge, so a removed account's name and counts go with
+    // it instead of lingering against a uid that no longer exists.
     setNames(next);
+    setStats(counts);
   };
 
   useEffect(() => {
     refresh();
   }, []);
 
-  const reveal = async (uid: string) => {
+  const reveal = async (uid: string, secretKeyHex: string) => {
     setBusyUid(uid);
     setRowError(null);
     try {
-      // POST with a body rather than ?uid=, so the target stays out of the
+      const proof = await proveOwnership(uid, ACTION_FOR.reveal, secretKeyHex);
-      // proxy's access log. The handler accepts either.
+      // POST with a body rather than ?uid=, so neither the target nor the
+      // signature reaches the proxy's access log. The handler accepts the uid
+      // either way; the proof must be in the body.
       const res = await fetch('/api/identity/reveal', {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ confirm: true, uid }),
+        body: JSON.stringify({ confirm: true, uid, ...proof }),
       });
       if (!res.ok) {
         setRowError({ uid, message: await errorMessage(res, 'Reveal failed') });
@@ -547,19 +707,34 @@ export default function Identity() {
     }
   };
 
-  const remove = async (uid: string) => {
+  const remove = async (uid: string, secretKeyHex: string) => {
     setBusyUid(uid);
     setRowError(null);
+    setNotice(null);
     try {
-      // The uid is mandatory: with more than one account the backend refuses an
+      const proof = await proveOwnership(uid, ACTION_FOR.remove, secretKeyHex);
-      // unqualified delete (400 uid_required) rather than guess.
+      // The uid is mandatory: the signature authorises one specific account, so
-      const res = await fetch(`/api/identity?uid=${encodeURIComponent(uid)}&confirm=true`, {
+      // the backend refuses an unqualified delete rather than guess a target.
+      const res = await fetch('/api/identity', {
         method: 'DELETE',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ confirm: true, uid, ...proof }),
       });
       if (!res.ok) {
         setRowError({ uid, message: await errorMessage(res, 'Remove failed') });
         return;
       }
+      // Report what the purge actually removed. "Account removed" on its own
+      // would not distinguish a clean delete from one that stranded the data.
+      const data = (await res.json().catch(() => ({}))) as { purged?: Stats };
+      const purged = data.purged;
+      setNotice(
+        purged && purged.records > 0
+          ? `Account removed. Purged ${purged.records.toLocaleString()} User Data Layer ` +
+            `${purged.records === 1 ? 'record' : 'records'} across ` +
+            `${purged.cids.toLocaleString()} ${purged.cids === 1 ? 'title' : 'titles'}.`
+          : 'Account removed. It held no User Data Layer records.'
+      );
       setPending(null);
       await refresh();
     } catch (e) {
@@ -574,9 +749,24 @@ export default function Identity() {
     refresh();
   };
 
+  const ask = (p: Pending) => {
+    setRowError(null);
+    setNotice(null);
+    setPending(p);
+  };
+
   const showList = !loading && !fetchError && !secret;
 
   return (
+    // App.tsx's content area is `overflow: hidden`, so every page owns its own
+    // scrolling (Files.tsx does the same). Without this the account list is
+    // simply clipped at the viewport with no scrollbar — invisible on a node
+    // with two accounts, and a dead end on one with fifteen.
+    //
+    // The scroller is the outer element and the padding lives inside it, so the
+    // scrollbar sits at the edge of the content area rather than floating in
+    // 2rem of whitespace, and `margin: 0 auto` still centres the column.
+    <div style={{ height: '100%', overflowY: 'auto', minHeight: 0 }}>
     <div style={{ padding: '2rem', maxWidth: '900px', margin: '0 auto' }}>
       <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center' }}>
         <h1 style={{ marginBottom: 0 }}>Identity</h1>
@@ -594,15 +784,26 @@ export default function Identity() {
 
       <div style={{ ...dangerPanelStyle, marginTop: 0, marginBottom: '1rem' }}>
         <p style={{ color: '#fecaca', margin: 0 }}>
-          <strong>Admin page — no authorisation happens here.</strong> <code>/api/identity/*</code>{' '}
+          <strong>The key is the only authority.</strong> Revealing or removing an account requires
-          asks no questions: anything that can reach this API can list, create, reveal or delete{' '}
+          that account's secret key, entered here and used to sign a one-time challenge in your
-          <em>any</em> account's private key. The only access control is the perimeter in front of
+          browser — there is no admin override, and holding this page is not one. Listing and
-          this port. Client-facing screens (meta-watch) authorise reveal and delete against the
+          creating accounts are still open to anything that can reach this API, so the perimeter in
-          caller's own session and expose no delete at all; this page has neither check. Treat
+          front of this port is what keeps the roster private.
-          reaching it as equivalent to holding every key on this node.
+        </p>
+        <p style={{ color: '#fecaca', margin: '0.5rem 0 0' }}>
+          What this does <em>not</em> defend against: anyone with filesystem access to{' '}
+          <code>{'{META_CORE_PATH}'}/identity/accounts/</code> reads every private key directly.
+          The keys are stored in plaintext, matching the trust model of the rest of{' '}
+          <code>/meta-core</code>.
         </p>
       </div>
 
+      {notice && (
+        <div style={{ ...cardStyle, border: '1px solid #0f3460' }}>
+          <p style={{ color: '#9ca3af', margin: 0 }}>{notice}</p>
+        </div>
+      )}
+
       {loading && <div style={cardStyle}>Loading…</div>}
 
       {fetchError && (
@@ -639,14 +840,12 @@ export default function Identity() {
               key={a.uid}
               account={a}
               name={names[a.uid]}
+              stats={stats === null ? null : stats[a.uid]}
               busy={busyUid === a.uid}
               disabled={busyUid !== null}
               pending={pending}
               error={rowError?.uid === a.uid ? rowError.message : null}
-              onAsk={(p) => {
+              onAsk={ask}
-                setRowError(null);
-                setPending(p);
-              }}
               onCancel={() => setPending(null)}
               onReveal={reveal}
               onRemove={remove}
@@ -655,5 +854,6 @@ export default function Identity() {
         </>
       )}
     </div>
+    </div>
   );
 }

docker/entrypoint.sh

@@ -10,7 +10,6 @@ set -e
 # Create required directories
 mkdir -p /meta-core/locks
 mkdir -p /meta-core/db/redis
-mkdir -p /meta-core/services
 mkdir -p /meta-core/mounts/errors
 mkdir -p /files
 mkdir -p /var/log/supervisor

docker/leader-election.sh

@@ -2,9 +2,13 @@
 # =============================================================================
 # Leader Election Script for meta-core
 #
-# Uses flock for leader election. Only the leader runs the full application
+# The flock here is a MUTEX, not service discovery. It is the only thing
-# stack (supervisord with Redis, meta-core, nginx, rclone, mount-watcher).
+# stopping two containers that mount the same /meta-core volume from putting
-# Followers remain dormant, periodically retrying to acquire the lock.
+# two Redis writers on one RDB/AOF. Sibling services no longer read anything
+# from this directory — they locate meta-core over UDP (meta-discovery v1, see
+# docs/project-architecture/service-discovery.md), so the kv-leader.info file
+# this script used to publish is gone. Keep the lock; it costs nothing and the
+# corruption it prevents is unrecoverable.
 #
 # Environment variables:
 #   META_CORE_PATH         - Path to meta-core data directory (default: /meta-core)
@@ -20,7 +24,6 @@ META_CORE_HTTP_PORT="${META_CORE_HTTP_PORT:-9000}"
 ELECTION_RETRY_SECS="${ELECTION_RETRY_SECS:-5}"
 
 LOCK_FILE="${META_CORE_PATH}/locks/kv-leader.lock"
-INFO_FILE="${META_CORE_PATH}/locks/kv-leader.info"
 SUPERVISORD_CONF="/etc/supervisor/conf.d/supervisord.conf"
 
 # Get the container's IP address
@@ -40,35 +43,13 @@ get_local_ip() {
     echo "$ip"
 }
 
-# Write leader info file (plain text API URL)
-write_leader_info() {
-    local ip=$(get_local_ip)
-    local api_url="http://${ip}:${META_CORE_HTTP_PORT}"
-
-    # Write atomically using temp file + rename
-    local temp_file="${INFO_FILE}.tmp"
-    echo "$api_url" > "$temp_file"
-    mv "$temp_file" "$INFO_FILE"
-
-    echo "[election] Wrote leader info: $api_url"
-}
-
-# Clean up leader info file on shutdown
-cleanup() {
-    echo "[election] Cleaning up..."
-    rm -f "$INFO_FILE"
-    exit 0
-}
-
 # Set up signal handlers for graceful shutdown
-trap cleanup SIGTERM SIGINT
 
 # Ensure lock directory exists
 mkdir -p "$(dirname "$LOCK_FILE")"
 
 echo "[election] Starting leader election..."
 echo "[election] Lock file: $LOCK_FILE"
-echo "[election] Info file: $INFO_FILE"
 
 # Open lock file for flock (file descriptor 200)
 exec 200>"$LOCK_FILE"
@@ -79,9 +60,6 @@ while true; do
     if flock -n 200; then
         echo "[election] Acquired flock - transitioning to LEADER"
 
-        # Write leader info before starting services
-        write_leader_info
-
         # exec supervisord - replaces this process
         # When supervisord exits, the flock is released automatically
         echo "[election] Starting supervisord..."

docker/nginx.conf

@@ -123,14 +123,10 @@ http {
         # =========================================================================
         # Service discovery
         # =========================================================================
-        location /services {
+        # meta-discovery v1 neighbours (supersedes /services, which stays
-            proxy_pass http://meta-core-api/services;
+        # while consumers migrate).
-            proxy_http_version 1.1;
+        location /neighbors {
-            proxy_set_header Host $host;
+            proxy_pass http://meta-core-api/neighbors;
-        }
-
-        location /services/ {
-            proxy_pass http://meta-core-api/services/;
             proxy_http_version 1.1;
             proxy_set_header Host $host;
         }

docs/meta-core-architecture.md

@@ -276,9 +276,8 @@ Bootstrap / discovery
   GET  /status
   GET  /leader
   GET  /urls
-  GET  /services         (alias: /api/services)
+  GET  /neighbors        (alias: /api/neighbors)
-  GET  /services/{name}
+  GET  /api/stats
-  GET  /services/cleanup/stats
 
 Metadata (primary surface for other services)
   GET    /meta
@@ -301,6 +300,7 @@ CID-addressed (public, auth-bypassed at the perimeter)
 
 Editor / KV / schema / snapshot
   GET /api/metadata/hash-ids
+  GET /api/files/tuples
   GET /api/metadata/list
   POST /api/metadata/search
   POST /api/metadata/batch
@@ -339,6 +339,9 @@ Watchers
 
 Admin
   POST /api/admin/migrate-dual-roots
+  POST /api/admin/sweep-literature-echoes   (dry-run unless ?apply=true;
+       strips query echoes off domain=literature fileType=card records —
+       see storage/literature_echo_sweep.go)
 
 WebDAV
   /webdav/...   (GET, PUT, DELETE, MKCOL, COPY, MOVE, PROPFIND)

go.mod

@@ -18,4 +18,5 @@ require (
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/yuin/gopher-lua v1.1.0 // indirect
+	golang.org/x/sys v0.28.0 // indirect
 )

go.sum

@@ -34,3 +34,5 @@ golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ss
 golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
 golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
 golang.org/x/sys v0.0.0-20190204203706-41f3e6584952/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
+golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

internal/api/admin_migrate.go

@@ -2,6 +2,7 @@ package api
 
 import (
 	"net/http"
+	"strconv"
 )
 
 // handleMigrateDualRoots triggers the one-shot sweep that re-unifies
@@ -28,3 +29,103 @@ func (s *Server) handleMigrateDualRoots(w http.ResponseWriter, r *http.Request)
 		"fixed":   fixed,
 	})
 }
+
+// handleMigrateDomainScreen triggers the one-shot sweep that rewrites the
+// retired `domain=film|tv` values to `screen` and backfills `workForm` from
+// `contentKind` (METADATA_KEYS.md §14.17). See
+// storage.MigrateDomainScreen for why the vocabulary change is paid in the
+// data rather than with a read-side alias.
+//
+// Returns {fixed: N} — records changed, not records examined. Safe to call
+// repeatedly: a record already on the current vocabulary is skipped.
+func (s *Server) handleMigrateDomainScreen(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	fixed, err := s.storage.MigrateDomainScreenWithTimeout()
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]interface{}{
+		"success": true,
+		"fixed":   fixed,
+	})
+}
+
+// handleSweepLiteratureEchoes removes query echoes stored on literature cards:
+// `anilistid` on a site card, and `workcid` / position keys on any card
+// (meta-read docs/reading-model.md §7). See storage.SweepLiteratureEchoes for
+// why chapters and anchor cards' ids are deliberately left alone.
+//
+// Dry-run unless `?apply=true`: unlike the migrations above this one deletes
+// keys, so a bare call only reports what it would delete. An unparseable
+// `apply` is a 400 rather than a silent dry run, so a typo cannot pass for a
+// sweep that ran.
+//
+// Returns {success, dryRun, planned, fixed, byKey} — planned/fixed count
+// records, byKey counts fields per key. Safe to call repeatedly: a swept
+// record plans nothing on the next pass.
+func (s *Server) handleSweepLiteratureEchoes(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	apply := false
+	if v := r.URL.Query().Get("apply"); v != "" {
+		parsed, err := strconv.ParseBool(v)
+		if err != nil {
+			writeError(w, http.StatusBadRequest, "apply must be true or false")
+			return
+		}
+		apply = parsed
+	}
+
+	res, err := s.storage.SweepLiteratureEchoesWithTimeout(apply)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]interface{}{
+		"success": true,
+		"dryRun":  !apply,
+		"planned": res.Planned,
+		"fixed":   res.Fixed,
+		"byKey":   res.ByKey,
+	})
+}
+
+// handleMigrateUserCids triggers the one-shot sweep that builds
+// `udl:idx:user:<uid>:cids` for User Data Layer records written before that
+// index existed. See storage.UDLBackfillUserCids.
+//
+// The index is what makes whole-profile export a set read instead of a
+// keyspace scan, and it is maintained by the upsert script from now on — so
+// this only ever matters once, for data already on disk. Until it has run, a
+// profile that predates the index exports as **empty**, which means a
+// cross-instance recovery reports success having restored nothing.
+//
+// Returns {fixed: N} — cids added, not cids examined. Safe to call repeatedly:
+// a second pass adds nothing.
+func (s *Server) handleMigrateUserCids(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	fixed, err := s.storage.UDLBackfillUserCids()
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	writeJSON(w, http.StatusOK, map[string]interface{}{
+		"success": true,
+		"fixed":   fixed,
+	})
+}

internal/api/admin_sweep_test.go

@@ -0,0 +1,93 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/alicebob/miniredis/v2"
+
+	"github.com/metazla/meta-core/internal/storage"
+)
+
+// newSweepTestServer is a Server over miniredis with one literature card
+// carrying a copied `workcid`.
+func newSweepTestServer(t *testing.T) *Server {
+	t.Helper()
+	mr := miniredis.RunT(t)
+	c := storage.NewClient("")
+	if err := c.Connect("redis://" + mr.Addr()); err != nil {
+		t.Fatalf("connect: %v", err)
+	}
+	t.Cleanup(func() { _ = c.Close() })
+	for k, v := range map[string]string{
+		"domain":   "literature",
+		"fileType": "card",
+		"workcid":  "bagdsaaaua5qw42lmnfzxi3lbnztwcorrga2tonzy",
+	} {
+		if err := c.SetProperty("card-1", k, v); err != nil {
+			t.Fatalf("seed %s: %v", k, err)
+		}
+	}
+	return &Server{storage: c}
+}
+
+type sweepResponse struct {
+	Success bool           `json:"success"`
+	DryRun  bool           `json:"dryRun"`
+	Planned int            `json:"planned"`
+	Fixed   int            `json:"fixed"`
+	ByKey   map[string]int `json:"byKey"`
+}
+
+func postSweep(t *testing.T, s *Server, query string) (*httptest.ResponseRecorder, sweepResponse) {
+	t.Helper()
+	rr := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodPost, "/api/admin/sweep-literature-echoes"+query, nil)
+	s.handleSweepLiteratureEchoes(rr, req)
+	var body sweepResponse
+	if rr.Code == http.StatusOK {
+		if err := json.Unmarshal(rr.Body.Bytes(), &body); err != nil {
+			t.Fatalf("decode %s: %v", rr.Body.String(), err)
+		}
+	}
+	return rr, body
+}
+
+// A bare call must never delete: the default is the dry run.
+func TestSweepLiteratureEchoes_DefaultsToDryRun(t *testing.T) {
+	s := newSweepTestServer(t)
+
+	rr, body := postSweep(t, s, "")
+	if rr.Code != http.StatusOK {
+		t.Fatalf("status = %d, body %s", rr.Code, rr.Body.String())
+	}
+	if !body.Success || !body.DryRun || body.Planned != 1 || body.Fixed != 0 || body.ByKey["workcid"] != 1 {
+		t.Errorf("dry run = %+v", body)
+	}
+	if v, _ := s.storage.GetProperty("card-1", "workcid"); v == "" {
+		t.Errorf("dry run deleted workcid")
+	}
+
+	rr, body = postSweep(t, s, "?apply=true")
+	if rr.Code != http.StatusOK {
+		t.Fatalf("status = %d, body %s", rr.Code, rr.Body.String())
+	}
+	if body.DryRun || body.Planned != 1 || body.Fixed != 1 || body.ByKey["workcid"] != 1 {
+		t.Errorf("apply = %+v", body)
+	}
+	if v, _ := s.storage.GetProperty("card-1", "workcid"); v != "" {
+		t.Errorf("apply left workcid = %q", v)
+	}
+}
+
+// A typo must not pass for a sweep that ran.
+func TestSweepLiteratureEchoes_RejectsUnparseableApply(t *testing.T) {
+	s := newSweepTestServer(t)
+
+	rr, _ := postSweep(t, s, "?apply=yes-please")
+	if rr.Code != http.StatusBadRequest {
+		t.Errorf("status = %d, want 400", rr.Code)
+	}
+}

internal/api/files_register.go

@@ -0,0 +1,132 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	"github.com/metazla/meta-core/internal/watcher"
+)
+
+// registerFileRequest is the body of POST /api/files/register.
+type registerFileRequest struct {
+	// Path relative to FILES_PATH, e.g. "plugin/subtitles/ab12….eng.srt".
+	Path string `json:"path"`
+}
+
+type registerFileResponse struct {
+	Root    string `json:"root"`
+	CID     string `json:"cid"`
+	Created bool   `json:"created"`
+	Path    string `json:"path"`
+	Size    int64  `json:"size"`
+}
+
+// pluginRelPath normalises a FILES_PATH-relative path and refuses anything
+// outside plugin/. Plugin output is the only tree a service may register this
+// way: /files/watch is the user's library and belongs to the watcher.
+func pluginRelPath(raw string) (string, bool) {
+	p := strings.TrimPrefix(filepath.ToSlash(strings.TrimSpace(raw)), "/")
+	if p == "" {
+		return "", false
+	}
+	for _, seg := range strings.Split(p, "/") {
+		if seg == ".." {
+			return "", false
+		}
+	}
+	clean := path.Clean(p)
+	if !strings.HasPrefix(clean, "plugin/") || clean == "plugin/" {
+		return "", false
+	}
+	return clean, true
+}
+
+// handleRegisterFile handles POST /api/files/register.
+//
+// Does for ONE file what the watcher does for every file it scans: midhash256
+// it, mint a root carrying filePath/sizeByte/mtimeNano, register the
+// cid:<midhash> alias, and append a file:events entry so meta-share's
+// ipfs_seed chunks, seeds and provides it.
+//
+// It exists for cores that run with ENABLE_FILE_WATCHER=false (a meta-watch
+// client box). Without it, bytes written under /files/plugin over WebDAV are
+// never resolvable by CID and never reach the swarm. Idempotent: the same
+// content at the same path returns the existing root with created=false.
+func (s *Server) handleRegisterFile(w http.ResponseWriter, r *http.Request) {
+	if s.storage == nil || !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	var req registerFileRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid JSON body")
+		return
+	}
+	rel, ok := pluginRelPath(req.Path)
+	if !ok {
+		writeError(w, http.StatusBadRequest, "path must be a file under plugin/")
+		return
+	}
+
+	fullPath := filepath.Join(s.config.FilesPath, filepath.FromSlash(rel))
+	absFiles, _ := filepath.Abs(filepath.Join(s.config.FilesPath, "plugin"))
+	absFull, _ := filepath.Abs(fullPath)
+	if !strings.HasPrefix(absFull, absFiles+string(filepath.Separator)) {
+		writeError(w, http.StatusBadRequest, "path must be a file under plugin/")
+		return
+	}
+
+	info, err := os.Stat(fullPath)
+	if err != nil {
+		writeError(w, http.StatusNotFound, "file not found")
+		return
+	}
+	if info.IsDir() {
+		writeError(w, http.StatusBadRequest, "path is a directory, not a file")
+		return
+	}
+
+	midhash, err := watcher.ComputeMidHash256(fullPath, info.Size())
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to hash file")
+		return
+	}
+
+	root, created, err := s.storage.RegisterFileTuple(fullPath, info.Size(), info.ModTime().UnixNano(), midhash)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	if created {
+		ev := watcher.FileEvent{
+			Type:       watcher.EventTypeAdd,
+			Path:       rel,
+			Size:       info.Size(),
+			MidHash256: midhash,
+			Timestamp:  watcher.NowMS(),
+		}
+		if err := watcher.PublishEvent(s.storage, ev); err != nil {
+			// The record is written and resolvable; only seeding is late.
+			writeError(w, http.StatusInternalServerError, "registered, but file event not published: "+err.Error())
+			return
+		}
+	}
+
+	status := http.StatusOK
+	if created {
+		status = http.StatusCreated
+	}
+	writeJSON(w, status, registerFileResponse{
+		Root:    root,
+		CID:     midhash,
+		Created: created,
+		Path:    rel,
+		Size:    info.Size(),
+	})
+}

internal/api/files_register_test.go

@@ -0,0 +1,144 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/alicebob/miniredis/v2"
+	"github.com/metazla/meta-core/internal/config"
+	"github.com/metazla/meta-core/internal/storage"
+)
+
+// newRegisterTestServer wires handleRegisterFile to an in-memory Redis and a
+// temp FILES_PATH. Built directly, not through NewServer, so no watcher runs —
+// which is exactly the configuration this route exists for.
+func newRegisterTestServer(t *testing.T) (*Server, string, *miniredis.Miniredis) {
+	t.Helper()
+	mr := miniredis.RunT(t)
+	c := storage.NewClient("")
+	if err := c.Connect("redis://" + mr.Addr()); err != nil {
+		t.Fatalf("connect to miniredis: %v", err)
+	}
+	t.Cleanup(func() { _ = c.Close() })
+	files := t.TempDir()
+	return &Server{storage: c, config: &config.Config{FilesPath: files}}, files, mr
+}
+
+func writeFixture(t *testing.T, files, rel, body string) string {
+	t.Helper()
+	full := filepath.Join(files, filepath.FromSlash(rel))
+	if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(full, []byte(body), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	return full
+}
+
+func postRegister(t *testing.T, s *Server, path string) (int, registerFileResponse) {
+	t.Helper()
+	body, _ := json.Marshal(registerFileRequest{Path: path})
+	req := httptest.NewRequest(http.MethodPost, "/api/files/register", strings.NewReader(string(body)))
+	rr := httptest.NewRecorder()
+	s.handleRegisterFile(rr, req)
+	var resp registerFileResponse
+	_ = json.Unmarshal(rr.Body.Bytes(), &resp)
+	return rr.Code, resp
+}
+
+func streamLen(t *testing.T, mr *miniredis.Miniredis) int {
+	t.Helper()
+	entries, err := mr.Stream("file:events")
+	if err != nil {
+		return 0
+	}
+	return len(entries)
+}
+
+// The whole point of the route: with the watcher off, a file written under
+// plugin/ becomes a record resolvable by its midhash, and meta-share hears
+// about it on file:events.
+func TestRegisterFile_MintsAliasAndPublishesEvent(t *testing.T) {
+	s, files, mr := newRegisterTestServer(t)
+	rel := "plugin/subtitles/ab12cd34.eng.srt"
+	full := writeFixture(t, files, rel, "1\n00:00:01,000 --> 00:00:02,000\nHello\n")
+
+	code, resp := postRegister(t, s, rel)
+	if code != http.StatusCreated || !resp.Created {
+		t.Fatalf("want 201 created, got %d %+v", code, resp)
+	}
+	if !strings.HasPrefix(resp.CID, "b") || resp.Root == "" {
+		t.Fatalf("want a multibase cid and a root, got %+v", resp)
+	}
+
+	root, err := s.storage.GetByCID(resp.CID)
+	if err != nil || root != resp.Root {
+		t.Fatalf("cid alias must resolve to the root: got %q err=%v, want %q", root, err, resp.Root)
+	}
+	if fp, _ := s.storage.GetProperty(resp.Root, "filePath"); fp != full {
+		t.Fatalf("filePath = %q, want %q", fp, full)
+	}
+
+	entries, err := mr.Stream("file:events")
+	if err != nil || len(entries) != 1 {
+		t.Fatalf("want exactly one file:events entry, got %d err=%v", len(entries), err)
+	}
+	vals := strings.Join(entries[0].Values, "|")
+	if !strings.Contains(vals, "midhash256|"+resp.CID) || !strings.Contains(vals, "path|"+rel) {
+		t.Fatalf("event must carry the midhash and the relative path, got %q", vals)
+	}
+}
+
+// Re-uploading the same subtitle is a no-op: same root, no second event (which
+// would make meta-share re-chunk and re-provide the file).
+func TestRegisterFile_IsIdempotent(t *testing.T) {
+	s, files, mr := newRegisterTestServer(t)
+	rel := "plugin/subtitles/same.eng.srt"
+	writeFixture(t, files, rel, "same bytes")
+
+	_, first := postRegister(t, s, rel)
+	code, second := postRegister(t, s, rel)
+	if code != http.StatusOK || second.Created {
+		t.Fatalf("second register must be 200 created=false, got %d %+v", code, second)
+	}
+	if second.Root != first.Root || second.CID != first.CID {
+		t.Fatalf("second register must return the same record: %+v vs %+v", second, first)
+	}
+	if n := streamLen(t, mr); n != 1 {
+		t.Fatalf("an idempotent re-register must not publish again, stream has %d", n)
+	}
+}
+
+// Only plugin output may be registered here. /files/watch is the user's
+// library and belongs to the watcher; traversal must not escape either.
+func TestRegisterFile_RejectsPathsOutsidePlugin(t *testing.T) {
+	s, files, _ := newRegisterTestServer(t)
+	writeFixture(t, files, "watch/movie.mkv", "x")
+	for _, p := range []string{
+		"", "plugin", "plugin/", "watch/movie.mkv", "/watch/movie.mkv",
+		"plugin/../watch/movie.mkv", "../etc/passwd", "plugin/../../etc/passwd",
+	} {
+		if code, _ := postRegister(t, s, p); code != http.StatusBadRequest {
+			t.Errorf("path %q: want 400, got %d", p, code)
+		}
+	}
+}
+
+func TestRegisterFile_MissingFileAndDirectory(t *testing.T) {
+	s, files, _ := newRegisterTestServer(t)
+	if code, _ := postRegister(t, s, "plugin/subtitles/nope.srt"); code != http.StatusNotFound {
+		t.Errorf("missing file: want 404, got %d", code)
+	}
+	if err := os.MkdirAll(filepath.Join(files, "plugin", "subtitles", "dir"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if code, _ := postRegister(t, s, "plugin/subtitles/dir"); code != http.StatusBadRequest {
+		t.Errorf("directory: want 400, got %d", code)
+	}
+}

internal/api/files_tuples.go

@@ -0,0 +1,74 @@
+package api
+
+import "net/http"
+
+// fileTupleJSON is one file-backed root on the wire.
+type fileTupleJSON struct {
+	HashID    string `json:"hashId"`
+	FilePath  string `json:"filePath"`
+	SizeByte  int64  `json:"sizeByte"`
+	MtimeNano int64  `json:"mtimeNano"`
+}
+
+// FileTuplesResponse is the body of GET /api/files/tuples.
+//
+// Files is a pointer so the summary form can omit it while the full form
+// always carries it — an empty library is `"files": []`, never an absent key,
+// which a client could mistake for a meta-core that lacks the rows.
+type FileTuplesResponse struct {
+	Files     *[]fileTupleJSON `json:"files,omitempty"`
+	Count     int              `json:"count"`
+	TotalSize int64            `json:"totalSize"`
+}
+
+// handleGetFileTuples handles GET /api/files/tuples.
+//
+// Lists the FILE-BACKED roots — records carrying filePath, sizeByte and
+// mtimeNano, i.e. what the watcher or /api/files/register minted — with their
+// sizes, plus the count and total. Gateway / cid-rooted records carry no file
+// and are not included; neither is a locator record that only merged a cache
+// file's metadata (it has no mtimeNano).
+//
+// It exists so a client never walks every hashId to answer "how many files,
+// how big": GetTuplesForAllFiles reads the three fields for every root in
+// chunked MGETs server-side (~250 round-trips for 82k roots, no SCAN), where
+// the client-side equivalent was one HTTP request per record.
+//
+// ?summary=1 omits the rows and returns only {count, totalSize}.
+func (s *Server) handleGetFileTuples(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	tuples, err := s.storage.GetTuplesForAllFiles()
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+
+	summary := r.URL.Query().Get("summary")
+	withRows := summary == "" || summary == "0" || summary == "false"
+
+	resp := FileTuplesResponse{Count: len(tuples)}
+	var rows []fileTupleJSON
+	if withRows {
+		rows = make([]fileTupleJSON, 0, len(tuples))
+	}
+	for _, t := range tuples {
+		resp.TotalSize += t.Size
+		if withRows {
+			rows = append(rows, fileTupleJSON{
+				HashID:    t.HashID,
+				FilePath:  t.FilePath,
+				SizeByte:  t.Size,
+				MtimeNano: t.MtimeNano,
+			})
+		}
+	}
+	if withRows {
+		resp.Files = &rows
+	}
+
+	writeJSON(w, http.StatusOK, resp)
+}

internal/api/files_tuples_test.go

@@ -0,0 +1,114 @@
+package api
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"sort"
+	"testing"
+
+	"github.com/alicebob/miniredis/v2"
+	"github.com/metazla/meta-core/internal/storage"
+)
+
+func newFileTuplesTestServer(t *testing.T) (*Server, *storage.Client) {
+	t.Helper()
+	mr := miniredis.RunT(t)
+	c := storage.NewClient("")
+	if err := c.Connect("redis://" + mr.Addr()); err != nil {
+		t.Fatalf("connect to miniredis: %v", err)
+	}
+	t.Cleanup(func() { _ = c.Close() })
+	return &Server{storage: c}, c
+}
+
+func getFileTuples(t *testing.T, s *Server, query string) (int, FileTuplesResponse) {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodGet, "/api/files/tuples"+query, nil)
+	rr := httptest.NewRecorder()
+	s.handleGetFileTuples(rr, req)
+	var resp FileTuplesResponse
+	_ = json.Unmarshal(rr.Body.Bytes(), &resp)
+	return rr.Code, resp
+}
+
+func mustMint(t *testing.T, c *storage.Client, path string, size, mtime int64) string {
+	t.Helper()
+	id, err := c.Mint(path, size, mtime)
+	if err != nil {
+		t.Fatalf("mint %s: %v", path, err)
+	}
+	return id
+}
+
+// Only records that are actually files count: a gateway record and a record
+// that merely carries a path + size (no mtimeNano) are both left out.
+func TestFileTuples_OnlyFileBackedRoots(t *testing.T) {
+	s, c := newFileTuplesTestServer(t)
+	a := mustMint(t, c, "/files/watch/a.mkv", 1000, 1)
+	b := mustMint(t, c, "/files/watch/b.mkv", 2500, 2)
+	if err := c.SetMetadataFlat("bagcsgatewayrecord", map[string]string{"title": "Some Release"}); err != nil {
+		t.Fatal(err)
+	}
+	if err := c.SetMetadataFlat("01partialroot", map[string]string{"filePath": "/files/cache/x.mkv", "sizeByte": "999"}); err != nil {
+		t.Fatal(err)
+	}
+
+	code, resp := getFileTuples(t, s, "")
+	if code != http.StatusOK {
+		t.Fatalf("want 200, got %d", code)
+	}
+	if resp.Count != 2 || resp.TotalSize != 3500 {
+		t.Fatalf("want count 2 / totalSize 3500, got %d / %d", resp.Count, resp.TotalSize)
+	}
+	if resp.Files == nil || len(*resp.Files) != 2 {
+		t.Fatalf("want 2 rows, got %+v", resp.Files)
+	}
+	got := []string{(*resp.Files)[0].HashID, (*resp.Files)[1].HashID}
+	want := []string{a, b}
+	sort.Strings(got)
+	sort.Strings(want)
+	if got[0] != want[0] || got[1] != want[1] {
+		t.Fatalf("want roots %v, got %v", want, got)
+	}
+}
+
+func TestFileTuples_SummaryOmitsRows(t *testing.T) {
+	s, c := newFileTuplesTestServer(t)
+	mustMint(t, c, "/files/watch/a.mkv", 1000, 1)
+	mustMint(t, c, "/files/watch/b.mkv", 2500, 2)
+
+	code, resp := getFileTuples(t, s, "?summary=1")
+	if code != http.StatusOK {
+		t.Fatalf("want 200, got %d", code)
+	}
+	if resp.Files != nil {
+		t.Fatalf("summary must omit rows, got %d", len(*resp.Files))
+	}
+	if resp.Count != 2 || resp.TotalSize != 3500 {
+		t.Fatalf("want count 2 / totalSize 3500, got %d / %d", resp.Count, resp.TotalSize)
+	}
+}
+
+// An empty library still carries "files": [] — clients treat an absent key as
+// "this meta-core cannot list files", so it must not disappear when empty.
+func TestFileTuples_EmptyLibraryKeepsFilesKey(t *testing.T) {
+	s, _ := newFileTuplesTestServer(t)
+
+	code, resp := getFileTuples(t, s, "")
+	if code != http.StatusOK {
+		t.Fatalf("want 200, got %d", code)
+	}
+	if resp.Files == nil || len(*resp.Files) != 0 || resp.Count != 0 {
+		t.Fatalf("want an empty files array and count 0, got %+v", resp)
+	}
+}
+
+func TestFileTuples_StorageNotConnected(t *testing.T) {
+	s := &Server{storage: storage.NewClient("")}
+
+	code, _ := getFileTuples(t, s, "")
+	if code != http.StatusServiceUnavailable {
+		t.Fatalf("want 503, got %d", code)
+	}
+}

internal/api/handlers.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/gorilla/mux"
 	"github.com/metazla/meta-core/internal/leader"
+	"github.com/metazla/meta-core/internal/meshdisco"
 )
 
 // contentTypeByExt maps file extensions to MIME types
@@ -547,62 +548,40 @@ func (s *Server) handleGetFileByCID(w http.ResponseWriter, r *http.Request) {
 	http.ServeContent(w, r, fileInfo.Name(), fileInfo.ModTime(), file)
 }
 
-// handleListServices handles GET /services and GET /api/services
+// handleListNeighbors handles GET /neighbors and GET /api/neighbors.
-// Supports optional ?current=<service-name> query parameter
+//
-func (s *Server) handleListServices(w http.ResponseWriter, r *http.Request) {
+// meta-discovery v1. The list is built from UDP announces held in memory, not
-	services, err := s.discovery.DiscoverAll()
+// from files under /meta-core/services, so it works across stacks that share a
-	if err != nil {
+// network but no volume. Instances of the same service are collapsed to the
-		writeError(w, http.StatusInternalServerError, err.Error())
+// most recent, which preserves the one-row-per-service shape the old
-		return
+// /api/services had. `?all=1` returns every instance, for debugging.
-	}
+func (s *Server) handleListNeighbors(w http.ResponseWriter, r *http.Request) {
-
 	response := map[string]interface{}{
-		"services": services,
+		"current":   s.config.ServiceName,
-		"count":    len(services),
+		"neighbors": []interface{}{},
-	}
+		"count":     0,
-
-	// Add 'current' field if query parameter is provided
-	current := r.URL.Query().Get("current")
-	if current != "" {
-		response["current"] = current
 	}
 
+	if s.mesh == nil {
+		// Discovery off or failed to bind. Report empty rather than 503 —
+		// the nav is decoration and callers already treat [] as "hide".
+		response["enabled"] = false
 		writeJSON(w, http.StatusOK, response)
-}
-
-// handleGetService handles GET /services/{name}
-func (s *Server) handleGetService(w http.ResponseWriter, r *http.Request) {
-	vars := mux.Vars(r)
-	name := vars["name"]
-
-	if name == "" {
-		writeError(w, http.StatusBadRequest, "service name is required")
 		return
 	}
 
-	service, err := s.discovery.Discover(name)
+	var list []meshdisco.Neighbor
-	if err != nil {
+	if r.URL.Query().Get("all") != "" {
-		writeError(w, http.StatusInternalServerError, err.Error())
+		list = s.mesh.Neighbors()
-		return
+	} else {
+		list = s.mesh.NeighborsByName()
 	}
 
-	if service == nil {
+	response["enabled"] = true
-		writeError(w, http.StatusNotFound, "service not found")
+	response["neighbors"] = list
-		return
+	response["count"] = len(list)
-	}
+	response["self"] = s.mesh.Self()
-
+	writeJSON(w, http.StatusOK, response)
-	writeJSON(w, http.StatusOK, service)
-}
-
-// handleCleanupStats handles GET /services/cleanup/stats
-func (s *Server) handleCleanupStats(w http.ResponseWriter, r *http.Request) {
-	if s.cleaner == nil {
-		writeError(w, http.StatusServiceUnavailable, "cleaner not initialized")
-		return
-	}
-
-	stats := s.cleaner.Stats()
-	writeJSON(w, http.StatusOK, stats)
 }
 
 // writeJSON writes a JSON response

internal/api/handlers_identity.go

@@ -3,11 +3,14 @@ package api
 import (
 	"encoding/base64"
 	"encoding/json"
+	"errors"
+	"log"
 	"net/http"
 	"strconv"
 	"strings"
 
 	"github.com/metazla/meta-core/internal/identity"
+	"github.com/metazla/meta-core/internal/storage"
 )
 
 // identityStatusResponse is the shape of GET /api/identity. The private key
@@ -59,12 +62,40 @@ type identityImportResponse struct {
 	Created bool `json:"created"`
 }
 
-// identityRevealRequest asks for an existing account's private key back. The
+// identityChallengeRequest asks for a one-shot challenge to sign.
-// key was shown once at generate; without a way to see it again, a client with
+type identityChallengeRequest struct {
-// a real sign-out has no recovery path for a user who never saved it.
+	UID    string `json:"uid"`
+	Action string `json:"action"`
+}
+
+type identityChallengeResponse struct {
+	Challenge string `json:"challenge"`
+	ExpiresAt int64  `json:"expiresAt"`
+}
+
+// identityProof is the proof-of-possession carried by reveal and delete: the
+// challenge text as issued, and a signature over it by the account's key.
+//
+// The signature is produced by whoever holds the key — the browser, locally.
+// It is NOT obtainable from POST /api/identity/sign, which refuses any payload
+// in the challenge domain; that refusal is what makes this proof mean
+// something on a node that stores every private key in plaintext.
+type identityProof struct {
+	Challenge string `json:"challenge"`
+	Signature string `json:"signature"`
+}
+
+// identityRevealRequest asks for an existing account's private key back.
+//
+// Gated on proof-of-possession, which makes it a "does this node hold the same
+// key I do" check rather than the recovery path it once was. That is the
+// deliberate consequence of the rule this file enforces: the private key, and
+// nothing else, is authority over the account. An operator with root on the box
+// can still read the file; an operator with only the API cannot.
 type identityRevealRequest struct {
 	Confirm bool   `json:"confirm"`
 	UID     string `json:"uid"`
+	identityProof
 }
 
 type identityRevealResponse struct {
@@ -76,6 +107,15 @@ type identityRevealResponse struct {
 type identityDeleteRequest struct {
 	Confirm bool   `json:"confirm"`
 	UID     string `json:"uid"`
+	identityProof
+}
+
+// identityDeleteResponse reports what the delete actually removed. The purge
+// counts are the point: "account removed" alone leaves the caller unable to
+// tell a clean removal from one that silently stranded a decade of ratings.
+type identityDeleteResponse struct {
+	UID    string               `json:"uid"`
+	Purged storage.UDLUserStats `json:"purged"`
 }
 
 type identitySignRequest struct {
@@ -114,6 +154,16 @@ type identitySignBatchResponse struct {
 // should page. Sized well above the longest real series (Supernatural, 327).
 const maxSignBatch = 1000
 
+// reservedPayloadMessage explains the one refusal the signing endpoints make.
+//
+// This is the load-bearing half of proof-of-possession on a node that holds
+// every private key: without it, a caller wanting to delete someone else's
+// account just asks meta-core to sign the challenge for them, and the gate on
+// reveal/delete becomes a formality. See identity.ChallengeDomain.
+const reservedPayloadMessage = "payload is in the reserved account-authorisation domain (" +
+	identity.ChallengeDomain + "…); meta-core will not sign one. " +
+	"Signing a challenge is what proves you hold the key, so it must be done where the key is."
+
 type identityAEADKeyResponse struct {
 	AEADKeyB64 string `json:"aeadKeyB64"`
 }
@@ -243,23 +293,105 @@ func (s *Server) handleIdentityImport(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
-// handleIdentityReveal returns an existing account's private key. Deliberately
+// handleIdentityChallenge issues the one-shot text a client signs to prove it
-// POST + explicit confirm (never a bare GET) so it cannot be triggered by a
+// holds an account's private key.
-// link or an image tag, and so it reads as the deliberate act it is. The
+//
-// endpoint is auth-gated at the perimeter like the rest of /api/identity/*.
+// Unauthenticated by design: a challenge is useless without the key, and
-func (s *Server) handleIdentityReveal(w http.ResponseWriter, r *http.Request) {
+// GET /api/identity/accounts already publishes every uid, so refusing to mint
-	var body identityRevealRequest
+// one for an unknown caller would protect nothing. Requiring the account to
-	_ = json.NewDecoder(r.Body).Decode(&body)
+// exist is for a clear error, not secrecy.
-	if !body.Confirm && r.URL.Query().Get("confirm") != "true" {
+func (s *Server) handleIdentityChallenge(w http.ResponseWriter, r *http.Request) {
-		writeErrorSlug(w, http.StatusBadRequest, "confirm_required",
+	var body identityChallengeRequest
-			"revealing a private key requires {\"confirm\": true} or ?confirm=true", false)
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid JSON body")
 		return
 	}
 	uid := strings.TrimSpace(body.UID)
+	if uid == "" {
+		writeErrorSlug(w, http.StatusBadRequest, "uid_required", "uid is required", false)
+		return
+	}
+	action := identity.Action(strings.TrimSpace(body.Action))
+	if !identity.ValidAction(action) {
+		writeErrorSlug(w, http.StatusBadRequest, "bad_action",
+			`action must be "reveal" or "delete"`, false)
+		return
+	}
+	if !identity.ExistsByUID(s.config.IdentityAccountsDir(), uid) {
+		writeErrorSlug(w, http.StatusNotFound, "no_identity", "no identity for the given uid", false)
+		return
+	}
+	text, expires, err := s.challenges.Issue(uid, action)
+	if err != nil {
+		if errors.Is(err, identity.ErrChallengeFull) {
+			writeErrorSlug(w, http.StatusServiceUnavailable, "challenges_full", err.Error(), true)
+			return
+		}
+		writeErrorSlug(w, http.StatusBadRequest, "bad_uid", err.Error(), false)
+		return
+	}
+	writeJSON(w, http.StatusOK, identityChallengeResponse{
+		Challenge: text,
+		ExpiresAt: expires.Unix(),
+	})
+}
+
+// requireProof resolves the target account and verifies the caller's
+// proof-of-possession for `action`. status == 0 means the proof held.
+//
+// The uid is mandatory here, unlike elsewhere in this file: the old "sole
+// account" fallback would have this pick a target the signature does not name,
+// and a proof that authorises an unnamed account authorises the wrong one as
+// soon as a second profile exists.
+func (s *Server) requireProof(uid string, proof identityProof, action identity.Action) (
+	id *identity.Identity, status int, slug, msg string,
+) {
+	uid = strings.TrimSpace(uid)
+	if uid == "" {
+		return nil, http.StatusBadRequest, "uid_required",
+			"uid is required: the signature authorises one specific account"
+	}
+	if proof.Challenge == "" || proof.Signature == "" {
+		return nil, http.StatusUnauthorized, "signature_required",
+			"this operation requires proof you hold the account's private key: " +
+				"POST /api/identity/challenge, sign the returned text, and resend it as {challenge, signature}"
+	}
+	sig, err := base64.StdEncoding.DecodeString(proof.Signature)
+	if err != nil {
+		return nil, http.StatusBadRequest, "bad_signature", "signature is not valid base64"
+	}
+	// Resolve before redeeming so a request naming a missing account does not
+	// burn a challenge it could not have used anyway.
+	id, status, slug, msg = s.resolveAccount(uid)
+	if status != 0 {
+		return nil, status, slug, msg
+	}
+	// Redeem first, verify second: the challenge is single-use either way, so a
+	// wrong signature costs the attacker a fresh round trip per guess rather
+	// than letting them grind one challenge offline against the same nonce.
+	if err := s.challenges.Redeem(proof.Challenge, uid, action); err != nil {
+		return nil, http.StatusUnauthorized, "bad_challenge", err.Error()
+	}
+	if err := identity.Verify(uid, []byte(proof.Challenge), sig); err != nil {
+		return nil, http.StatusUnauthorized, "bad_signature", err.Error()
+	}
+	return id, 0, "", ""
+}
+
+// handleIdentityReveal returns an existing account's private key to a caller
+// that proves it already holds that key.
+//
+// Deliberately POST (never a bare GET) so it cannot be triggered by a link or
+// an image tag. The proof is what actually guards it: before this gate existed,
+// anything that could reach the port could read every private key on the node.
+func (s *Server) handleIdentityReveal(w http.ResponseWriter, r *http.Request) {
+	var body identityRevealRequest
+	_ = json.NewDecoder(r.Body).Decode(&body)
+	uid := strings.TrimSpace(body.UID)
 	if uid == "" {
 		uid = strings.TrimSpace(r.URL.Query().Get("uid"))
 	}
-	id, status, slug, msg := s.resolveAccount(uid)
+	id, status, slug, msg := s.requireProof(uid, body.identityProof, identity.ActionReveal)
 	if status != 0 {
 		writeErrorSlug(w, status, slug, msg, false)
 		return
@@ -271,46 +403,62 @@ func (s *Server) handleIdentityReveal(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
+// handleIdentityDelete removes one account and everything it wrote.
+//
+// Two things happen, in this order and no other:
+//
+//  1. the account's User Data Layer rows are purged (cells plus every index
+//     that names the uid, including the cid-scoped ones shared with other
+//     accounts);
+//  2. the keypair file is removed.
+//
+// Purge-then-delete so a failure never strands data: if the purge errors the
+// key is still on disk, the account still exists, and the caller can retry.
+// The reverse order would leave rows nobody can ever attribute, reach or
+// rewrite — the orphaning this endpoint exists to prevent.
+//
+// What deletion still does NOT do, and cannot: records already signed under
+// this uid and replicated to other peers keep verifying there. Removing a key
+// is not a recall.
 func (s *Server) handleIdentityDelete(w http.ResponseWriter, r *http.Request) {
 	var body identityDeleteRequest
-	// Tolerate empty body — confirm flag in a query param is also acceptable
+	// Tolerate an empty body so the uid may ride in the query — meta-watch's
-	// for shells where sending a JSON body with DELETE is awkward.
+	// proxy puts it there. The proof itself must be in the body: a signature in
+	// a URL ends up in every access log between here and the browser.
 	_ = json.NewDecoder(r.Body).Decode(&body)
-	if !body.Confirm && r.URL.Query().Get("confirm") != "true" {
-		writeErrorSlug(w, http.StatusBadRequest, "confirm_required",
-			"identity deletion requires {\"confirm\": true} or ?confirm=true", false)
-		return
-	}
-	dir := s.config.IdentityAccountsDir()
 	uid := strings.TrimSpace(body.UID)
 	if uid == "" {
 		uid = strings.TrimSpace(r.URL.Query().Get("uid"))
 	}
-	if uid == "" {
+	id, status, slug, msg := s.requireProof(uid, body.identityProof, identity.ActionDelete)
-		// Back-compat: with no uid, delete the sole account. Ambiguous (and so
+	if status != 0 {
-		// refused) once more than one account exists.
+		writeErrorSlug(w, status, slug, msg, false)
-		list, err := identity.List(dir)
+		return
+	}
+
+	// A purge needs storage. Refusing here — rather than deleting the key and
+	// reporting the purge as "0 records" — is the difference between a retry
+	// and permanent orphaned data: once the key is gone the account cannot be
+	// named for a second attempt through this API.
+	if !s.storage.IsConnected() {
+		writeErrorSlug(w, http.StatusServiceUnavailable, "storage_unavailable",
+			"storage is not connected; refusing to delete the key while its data cannot be purged", true)
+		return
+	}
+	purged, err := s.storage.UDLPurgeUser(id.UID)
 	if err != nil {
-			writeError(w, http.StatusInternalServerError, err.Error())
+		writeErrorSlug(w, http.StatusInternalServerError, "purge_failed",
+			"could not purge this account's data; the account was NOT deleted: "+err.Error(), true)
 		return
 	}
-		switch len(list) {
+
-		case 0:
+	if err := identity.DeleteByUID(s.config.IdentityAccountsDir(), id.UID); err != nil {
-			w.WriteHeader(http.StatusNoContent) // idempotent
+		writeErrorSlug(w, http.StatusInternalServerError, "delete_failed", err.Error(), false)
-			return
-		case 1:
-			uid = list[0].UID
-		default:
-			writeErrorSlug(w, http.StatusBadRequest, "uid_required",
-				"multiple accounts exist; specify uid to delete", false)
 		return
 	}
-	}
+	log.Printf("[API] Deleted account %s and purged %d User Data Layer records across %d cids",
-	if err := identity.DeleteByUID(dir, uid); err != nil {
+		id.UID, purged.Records, purged.Cids)
-		writeError(w, http.StatusInternalServerError, err.Error())
+	writeJSON(w, http.StatusOK, identityDeleteResponse{UID: id.UID, Purged: purged})
-		return
-	}
-	w.WriteHeader(http.StatusNoContent)
 }
 
 func (s *Server) handleIdentitySign(w http.ResponseWriter, r *http.Request) {
@@ -333,6 +481,10 @@ func (s *Server) handleIdentitySign(w http.ResponseWriter, r *http.Request) {
 		writeError(w, http.StatusBadRequest, "bytesB64 is not valid base64")
 		return
 	}
+	if identity.IsChallengePayload(raw) {
+		writeErrorSlug(w, http.StatusForbidden, "reserved_payload", reservedPayloadMessage, false)
+		return
+	}
 	sig, err := identity.Sign(id, raw)
 	if err != nil {
 		writeError(w, http.StatusInternalServerError, err.Error())
@@ -380,6 +532,11 @@ func (s *Server) handleIdentitySignBatch(w http.ResponseWriter, r *http.Request)
 			writeError(w, http.StatusBadRequest, "payloadsB64["+strconv.Itoa(i)+"] is not valid base64")
 			return
 		}
+		if identity.IsChallengePayload(raw) {
+			writeErrorSlug(w, http.StatusForbidden, "reserved_payload",
+				"payloadsB64["+strconv.Itoa(i)+"]: "+reservedPayloadMessage, false)
+			return
+		}
 		sig, err := identity.Sign(id, raw)
 		if err != nil {
 			writeError(w, http.StatusInternalServerError, err.Error())

internal/api/identity_gate_test.go

@@ -0,0 +1,257 @@
+package api
+
+// End-to-end exercise of the account gate against a live router + miniredis:
+// generate -> write UDL rows -> stats -> challenge -> sign -> delete -> verify
+// both the key and every row are gone. Deliberately drives the real HTTP
+// handlers rather than the packages beneath them, because the bugs that matter
+// here (a challenge accepted for the wrong action, a purge that runs after the
+// key is gone) live in the wiring.
+
+import (
+	"bytes"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/alicebob/miniredis/v2"
+	"github.com/gorilla/mux"
+	"github.com/metazla/meta-core/internal/config"
+	"github.com/metazla/meta-core/internal/identity"
+	"github.com/metazla/meta-core/internal/storage"
+)
+
+func newTestServer(t *testing.T) *Server {
+	t.Helper()
+	mr := miniredis.RunT(t)
+	stor := storage.NewClient("")
+	if err := stor.Connect("redis://" + mr.Addr()); err != nil {
+		t.Fatalf("connect: %v", err)
+	}
+	t.Cleanup(func() { _ = stor.Close() })
+
+	s := &Server{
+		config:     &config.Config{MetaCorePath: t.TempDir()},
+		storage:    stor,
+		challenges: identity.NewChallengeStore(),
+		router:     mux.NewRouter(),
+	}
+	s.setupIdentityTestRoutes()
+	return s
+}
+
+// Only the routes under test, so this does not depend on every other subsystem
+// booting.
+func (s *Server) setupIdentityTestRoutes() {
+	s.router.HandleFunc("/api/identity/accounts", s.handleIdentityAccounts).Methods("GET")
+	s.router.HandleFunc("/api/identity/challenge", s.handleIdentityChallenge).Methods("POST")
+	s.router.HandleFunc("/api/identity/generate", s.handleIdentityGenerate).Methods("POST")
+	s.router.HandleFunc("/api/identity/reveal", s.handleIdentityReveal).Methods("POST")
+	s.router.HandleFunc("/api/identity", s.handleIdentityDelete).Methods("DELETE")
+	s.router.HandleFunc("/api/identity/sign", s.handleIdentitySign).Methods("POST")
+	s.router.HandleFunc("/api/udl/users/stats", s.handleUDLUserStats).Methods("GET")
+}
+
+func do(t *testing.T, s *Server, method, path string, body any) (*httptest.ResponseRecorder, map[string]any) {
+	t.Helper()
+	var rdr *bytes.Reader
+	if body != nil {
+		b, _ := json.Marshal(body)
+		rdr = bytes.NewReader(b)
+	} else {
+		rdr = bytes.NewReader(nil)
+	}
+	req := httptest.NewRequest(method, path, rdr)
+	req.Header.Set("Content-Type", "application/json")
+	rec := httptest.NewRecorder()
+	s.router.ServeHTTP(rec, req)
+	out := map[string]any{}
+	_ = json.Unmarshal(rec.Body.Bytes(), &out)
+	return rec, out
+}
+
+// signAs produces the proof a browser would, from the raw key.
+func signAs(t *testing.T, privHex, challenge string) map[string]any {
+	t.Helper()
+	raw, err := hex.DecodeString(privHex)
+	if err != nil {
+		t.Fatalf("decode key: %v", err)
+	}
+	id, err := identity.Import(hex.EncodeToString(raw))
+	if err != nil {
+		t.Fatalf("import: %v", err)
+	}
+	sig, err := identity.Sign(id, []byte(challenge))
+	if err != nil {
+		t.Fatalf("sign: %v", err)
+	}
+	return map[string]any{
+		"challenge": challenge,
+		"signature": base64.StdEncoding.EncodeToString(sig),
+	}
+}
+
+func TestE2E_DeleteRequiresProofAndPurgesEverything(t *testing.T) {
+	s := newTestServer(t)
+
+	rec, gen := do(t, s, "POST", "/api/identity/generate", nil)
+	if rec.Code != http.StatusCreated {
+		t.Fatalf("generate: %d %s", rec.Code, rec.Body)
+	}
+	uid := gen["uid"].(string)
+	priv := gen["privateKeyHex"].(string)
+
+	// Some data to lose.
+	for _, cell := range [][2]string{{"cidA", "like"}, {"cidA", "rating"}, {"cidB", "seek"}} {
+		if ok, err := s.storage.UDLUpsertIfNewer(uid, cell[0], cell[1], 1, 100, "rec", "", false, false); err != nil || !ok {
+			t.Fatalf("seed: %v", err)
+		}
+	}
+
+	// The count the UI shows in the confirmation.
+	rec, stats := do(t, s, "GET", "/api/udl/users/stats", nil)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("stats: %d %s", rec.Code, rec.Body)
+	}
+	users := stats["users"].(map[string]any)
+	mine := users[uid].(map[string]any)
+	if mine["records"].(float64) != 3 || mine["cids"].(float64) != 2 {
+		t.Fatalf("stats = %v, want 3 records / 2 cids", mine)
+	}
+
+	// Unsigned delete must be refused, and must not have touched anything.
+	rec, body := do(t, s, "DELETE", "/api/identity", map[string]any{"uid": uid, "confirm": true})
+	if rec.Code != http.StatusUnauthorized || body["error"] != "signature_required" {
+		t.Fatalf("unsigned delete = %d %v, want 401 signature_required", rec.Code, body)
+	}
+	if !identity.ExistsByUID(s.config.IdentityAccountsDir(), uid) {
+		t.Fatal("a refused delete removed the key anyway")
+	}
+
+	// meta-core must refuse to sign the caller's authorisation for them —
+	// without this the gate is decoration on a node holding every key.
+	ch, _, err := s.challenges.Issue(uid, identity.ActionDelete)
+	if err != nil {
+		t.Fatalf("issue: %v", err)
+	}
+	rec, body = do(t, s, "POST", "/api/identity/sign", map[string]any{
+		"uid":      uid,
+		"bytesB64": base64.StdEncoding.EncodeToString([]byte(ch)),
+	})
+	if rec.Code != http.StatusForbidden || body["error"] != "reserved_payload" {
+		t.Fatalf("sign of a challenge = %d %v, want 403 reserved_payload", rec.Code, body)
+	}
+
+	// A challenge minted for reveal must not authorise a delete.
+	rec, chBody := do(t, s, "POST", "/api/identity/challenge", map[string]any{"uid": uid, "action": "reveal"})
+	if rec.Code != http.StatusOK {
+		t.Fatalf("challenge: %d %s", rec.Code, rec.Body)
+	}
+	proof := signAs(t, priv, chBody["challenge"].(string))
+	req := map[string]any{"uid": uid, "confirm": true}
+	for k, v := range proof {
+		req[k] = v
+	}
+	rec, body = do(t, s, "DELETE", "/api/identity", req)
+	if rec.Code != http.StatusUnauthorized {
+		t.Fatalf("reveal challenge used for delete = %d %v, want 401", rec.Code, body)
+	}
+
+	// The real thing.
+	rec, chBody = do(t, s, "POST", "/api/identity/challenge", map[string]any{"uid": uid, "action": "delete"})
+	if rec.Code != http.StatusOK {
+		t.Fatalf("challenge: %d %s", rec.Code, rec.Body)
+	}
+	proof = signAs(t, priv, chBody["challenge"].(string))
+	req = map[string]any{"uid": uid, "confirm": true}
+	for k, v := range proof {
+		req[k] = v
+	}
+	rec, body = do(t, s, "DELETE", "/api/identity", req)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("signed delete = %d %s", rec.Code, rec.Body)
+	}
+	purged := body["purged"].(map[string]any)
+	if purged["records"].(float64) != 3 || purged["cids"].(float64) != 2 {
+		t.Fatalf("purged = %v, want 3 records / 2 cids", purged)
+	}
+
+	// Key gone.
+	if identity.ExistsByUID(s.config.IdentityAccountsDir(), uid) {
+		t.Fatal("the account file survived the delete")
+	}
+	// Data gone — the orphaning this whole change exists to prevent.
+	after, err := s.storage.UDLAllUserStats()
+	if err != nil {
+		t.Fatalf("stats after: %v", err)
+	}
+	if got, present := after[uid]; present {
+		t.Fatalf("deleted account still holds %+v", got)
+	}
+	for _, cid := range []string{"cidA", "cidB"} {
+		uids, err := s.storage.UDLCidUsers(cid)
+		if err != nil {
+			t.Fatalf("cid users: %v", err)
+		}
+		if len(uids) != 0 {
+			t.Fatalf("%s still names %v after the purge", cid, uids)
+		}
+	}
+
+	// The challenge is single-use, so replaying the same proof does nothing.
+	rec, _ = do(t, s, "DELETE", "/api/identity", req)
+	if rec.Code == http.StatusOK {
+		t.Fatal("a replayed proof must not succeed")
+	}
+}
+
+func TestE2E_RevealRequiresProof(t *testing.T) {
+	s := newTestServer(t)
+	_, gen := do(t, s, "POST", "/api/identity/generate", nil)
+	uid := gen["uid"].(string)
+	priv := gen["privateKeyHex"].(string)
+
+	rec, body := do(t, s, "POST", "/api/identity/reveal", map[string]any{"uid": uid, "confirm": true})
+	if rec.Code != http.StatusUnauthorized || body["error"] != "signature_required" {
+		t.Fatalf("unsigned reveal = %d %v, want 401 signature_required", rec.Code, body)
+	}
+
+	_, chBody := do(t, s, "POST", "/api/identity/challenge", map[string]any{"uid": uid, "action": "reveal"})
+	proof := signAs(t, priv, chBody["challenge"].(string))
+	req := map[string]any{"uid": uid, "confirm": true}
+	for k, v := range proof {
+		req[k] = v
+	}
+	rec, body = do(t, s, "POST", "/api/identity/reveal", req)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("signed reveal = %d %s", rec.Code, rec.Body)
+	}
+	if body["privateKeyHex"] != priv {
+		t.Fatal("reveal returned a different key than generate did")
+	}
+}
+
+// Another account's key must not authorise this one, even with a challenge
+// minted for the right uid and action.
+func TestE2E_AnotherAccountsKeyIsRefused(t *testing.T) {
+	s := newTestServer(t)
+	_, alice := do(t, s, "POST", "/api/identity/generate", nil)
+	_, mallory := do(t, s, "POST", "/api/identity/generate", nil)
+
+	uid := alice["uid"].(string)
+	_, chBody := do(t, s, "POST", "/api/identity/challenge", map[string]any{"uid": uid, "action": "delete"})
+	proof := signAs(t, mallory["privateKeyHex"].(string), chBody["challenge"].(string))
+	req := map[string]any{"uid": uid, "confirm": true}
+	for k, v := range proof {
+		req[k] = v
+	}
+	rec, body := do(t, s, "DELETE", "/api/identity", req)
+	if rec.Code != http.StatusUnauthorized || body["error"] != "bad_signature" {
+		t.Fatalf("mallory deleting alice = %d %v, want 401 bad_signature", rec.Code, body)
+	}
+	if !identity.ExistsByUID(s.config.IdentityAccountsDir(), uid) {
+		t.Fatal("alice's account was deleted by mallory's signature")
+	}
+}

internal/api/metadata.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"net/http"
 	"strconv"
-	"strings"
 
 	"github.com/gorilla/mux"
 )
@@ -39,6 +38,36 @@ type MetadataSearchRequest struct {
 	Property      string `json:"property,omitempty"`
 	PropertyValue string `json:"propertyValue,omitempty"`
 	Limit         int    `json:"limit,omitempty"`
+
+	// Filters is the structured form: AND across entries, OR within an
+	// entry's Values. Evaluated in memory against the search index alongside
+	// the free-text Query, so an id-anchored lookup costs a map probe per
+	// record rather than a Redis round-trip per record.
+	//
+	// Property/PropertyValue is the single-filter legacy shape and folds into
+	// this list (see normalizedFilters) with Exact=false, preserving its
+	// substring semantics byte-for-byte.
+	Filters []MetadataFilter `json:"filters,omitempty"`
+}
+
+// MetadataFilter is one structured constraint on a record.
+//
+// A record satisfies it when ANY of Values matches, and a search result must
+// satisfy EVERY filter (OR within, AND across). An entry with no usable value
+// constrains nothing — same rule the gateway's `genres_filter_matches` uses, so
+// a caller that lowers an empty filter doesn't accidentally empty the result.
+type MetadataFilter struct {
+	// Property is the field name, WITHOUT a key-set suffix: `genres`, not
+	// `genres/Action`. Both storage shapes are probed — see recordMatchesFilter.
+	Property string `json:"property"`
+	// Values are OR'd. Compared case-insensitively.
+	Values []string `json:"values,omitempty"`
+	// Exact selects CSV-exact comparison (the semantics meta-gateway's
+	// `any_csv_value_matches` applies at its own Layer-B re-filter) over
+	// substring containment. Callers doing identity lookups want this: with a
+	// result limit, a substring match on `tmdbid=1405` also admits `21405` and
+	// can crowd the real matches out of the page.
+	Exact bool `json:"exact,omitempty"`
 }
 
 // MetadataSearchResult is a single search result
@@ -415,65 +444,18 @@ func (s *Server) handleSearchMetadata(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Free-text query: served from the in-memory search index (search_index.go)
+	// Everything else — free text, structured filters, both, or neither
-	// so we match in memory instead of doing a SCAN+MGET Redis round-trip per
+	// (which returns the first `limit`) — is served from the in-memory search
-	// record (that was 40s+ over ~72k records). Full metadata is fetched only
+	// index (search_index.go). Matching and the returned metadata both come
-	// for the <=limit matches.
+	// from memory, so a query costs zero Redis round-trips.
-	if req.Query != "" && req.Property == "" {
+	//
+	// There is deliberately no second path. The property branch used to fall
+	// through to a `GetAllHashIDs` + per-record `GetMetadataFlat` scan, which
+	// is what made an id-anchored lookup 3.63s over ~20k records (vs 10ms for
+	// the free-text branch on the same corpus) and kept meta-core out of the
+	// gateway's anchored search path entirely. The index already holds every
+	// field of every record, so that scan was re-reading data it had in hand.
 	s.serveIndexedSearch(w, req)
-		return
-	}
-
-	// Property filter (rare) or empty query (returns the first `limit`): the
-	// legacy scan. Empty query only fetches `limit` records; property search is
-	// low-volume and not on the hot search path.
-	allHashIDs, err := s.storage.GetAllHashIDs()
-	if err != nil {
-		writeError(w, http.StatusInternalServerError, err.Error())
-		return
-	}
-
-	var results []MetadataSearchResult
-	total := len(allHashIDs)
-
-	for _, hashID := range allHashIDs {
-		if len(results) >= req.Limit {
-			break
-		}
-
-		metadata, err := s.storage.GetMetadataFlat(hashID)
-		if err != nil || metadata == nil {
-			continue
-		}
-
-		matches := false
-
-		// Property search
-		if req.Property != "" && req.PropertyValue != "" {
-			value, ok := metadata[req.Property]
-			if ok && strings.Contains(strings.ToLower(value), strings.ToLower(req.PropertyValue)) {
-				matches = true
-			}
-		}
-
-		// If no query or property filter, return all
-		if req.Query == "" && req.Property == "" {
-			matches = true
-		}
-
-		if matches {
-			results = append(results, MetadataSearchResult{
-				HashID:   hashID,
-				Metadata: metadata,
-			})
-		}
-	}
-
-	writeJSON(w, http.StatusOK, MetadataSearchResponse{
-		Results: results,
-		Count:   len(results),
-		Total:   total,
-	})
 }
 
 // handleBatchUpdate handles POST /api/metadata/batch

internal/api/search_filter_test.go

@@ -0,0 +1,211 @@
+package api
+
+import "testing"
+
+// Tests for the structured-filter matcher that lets meta-core answer an
+// id-anchored query from the in-memory search index (search_index.go).
+//
+// Why this matters beyond "filters work": meta-core is a *coarse pre-filter*
+// for meta-gateway, which re-evaluates every record it emits through its own
+// `query_eval::record_matches`. So the property that has to hold is that this
+// matcher stays a SUPERSET of that one — it may admit records the gateway will
+// drop, but it must never drop a record the gateway would have kept. Every
+// case below is written from that angle:
+//
+//   - key-set fields (`genres/Action`) must match a `genres:action` filter, or
+//     card-tier records vanish from a genre-scoped query;
+//   - a missing field fails CLOSED, matching record_matches;
+//   - an empty/unusable filter constrains NOTHING, so a caller that lowers a
+//     blank filter gets its results rather than an empty page.
+
+func f(property string, exact bool, values ...string) MetadataFilter {
+	return MetadataFilter{Property: property, Values: values, Exact: exact}
+}
+
+func TestRecordMatchesFilter(t *testing.T) {
+	fields := map[string]string{
+		"fileType":               "video",
+		"videoType":              "tv,anime",
+		"tmdbid":                 "1405",
+		"genres/Action":          "true",
+		"genres/Science Fiction": "true",
+		"source/gateway:nyaa.si": "true",
+		"categories/XXX":         "true",
+		"retracted":              "false",
+	}
+
+	cases := []struct {
+		name   string
+		filter MetadataFilter
+		want   bool
+	}{
+		// Flat scalar.
+		{"flat exact hit", f("fileType", true, "video"), true},
+		{"flat exact miss", f("fileType", true, "audio"), false},
+		{"flat exact is case-insensitive", f("fileType", true, "VIDEO"), true},
+
+		// csv-set field: each comma piece is compared independently.
+		{"csv member hit", f("videoType", true, "anime"), true},
+		{"csv member miss", f("videoType", true, "movie"), false},
+
+		// Exact vs contains — the reason Exact exists. A substring match on an
+		// identity field admits neighbours and, under a result limit, crowds
+		// the real matches off the page.
+		{"contains admits a superstring", f("tmdbid", false, "140"), true},
+		{"exact rejects a superstring", f("tmdbid", true, "140"), false},
+		{"exact accepts the whole value", f("tmdbid", true, "1405"), true},
+
+		// Key-set shape. The stored member is verbatim (`genres/Action`) while
+		// query values arrive lowercased, so the case-insensitive sweep is what
+		// makes a genre-scoped row work at all.
+		{"key-set exact casing", f("genres", true, "Action"), true},
+		{"key-set lowercased query", f("genres", true, "action"), true},
+		{"key-set with a space", f("genres", true, "science fiction"), true},
+		{"key-set miss", f("genres", true, "horror"), false},
+		{"key-set label containing a colon", f("source", true, "gateway:nyaa.si"), true},
+
+		// OR within one filter's values.
+		{"or hits on the second value", f("fileType", true, "audio", "video"), true},
+		{"or misses on all values", f("fileType", true, "audio", "image"), false},
+
+		// Fail-closed on an absent field — mirrors record_matches, and is what
+		// keeps a filtered query from returning unrelated records.
+		{"absent field fails closed", f("imdbid", true, "tt0903747"), false},
+
+		// A filter that constrains nothing must not empty the result.
+		{"no values constrains nothing", f("fileType", true), true},
+		{"blank value constrains nothing", f("fileType", true, "  "), true},
+		{"no property constrains nothing", f("", true, "video"), true},
+
+		// A FLAT field whose value happens to be "false" is still a value, and
+		// an exact filter for it matches. Only the key-set arm treats "false"
+		// as non-membership (pinned in the test below).
+		{"flat field valued false still matches", f("retracted", true, "false"), true},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := recordMatchesFilter(fields, &tc.filter); got != tc.want {
+				t.Fatalf("recordMatchesFilter(%+v) = %v, want %v", tc.filter, got, tc.want)
+			}
+		})
+	}
+}
+
+// `retracted = "false"` is a flat field, not a key-set member, so the flat arm
+// legitimately matches the literal string "false". The key-set arm is what must
+// treat it as non-membership — pinned separately so the two arms don't get
+// conflated if either is refactored.
+func TestFalseyKeySetMemberIsNotMembership(t *testing.T) {
+	fields := map[string]string{"genres/Action": "false", "genres/Drama": "0"}
+	for _, v := range []string{"Action", "Drama"} {
+		filter := f("genres", true, v)
+		if recordMatchesFilter(fields, &filter) {
+			t.Fatalf("genres/%s with a falsey value must not assert membership", v)
+		}
+	}
+}
+
+func TestRecordMatchesFiltersIsAndAcrossEntries(t *testing.T) {
+	fields := map[string]string{"fileType": "video", "season": "2"}
+
+	all := []MetadataFilter{f("fileType", true, "video"), f("season", true, "2")}
+	if !recordMatchesFilters(fields, all) {
+		t.Fatal("a record satisfying every filter must match")
+	}
+
+	one := []MetadataFilter{f("fileType", true, "video"), f("season", true, "3")}
+	if recordMatchesFilters(fields, one) {
+		t.Fatal("filters are AND across entries — one miss must reject the record")
+	}
+
+	if !recordMatchesFilters(fields, nil) {
+		t.Fatal("no filters must match everything")
+	}
+}
+
+// The legacy Property/PropertyValue pair keeps its substring semantics: it is
+// the shape existing callers already use, and tightening it silently would
+// change results for them. New callers pass Filters and opt into Exact.
+func TestNormalizedFiltersFoldsTheLegacyPair(t *testing.T) {
+	got := normalizedFilters(MetadataSearchRequest{Property: "tmdbid", PropertyValue: "1405"})
+	if len(got) != 1 {
+		t.Fatalf("legacy pair must fold into exactly one filter, got %d", len(got))
+	}
+	if got[0].Property != "tmdbid" || len(got[0].Values) != 1 || got[0].Values[0] != "1405" {
+		t.Fatalf("legacy pair folded incorrectly: %+v", got[0])
+	}
+	if got[0].Exact {
+		t.Fatal("the legacy pair must stay substring (Exact=false) for compatibility")
+	}
+
+	// A half-specified pair is not a filter — it must not become one that
+	// matches nothing and empties the response.
+	if n := len(normalizedFilters(MetadataSearchRequest{Property: "tmdbid"})); n != 0 {
+		t.Fatalf("a property with no value must not fold into a filter, got %d", n)
+	}
+	if n := len(normalizedFilters(MetadataSearchRequest{PropertyValue: "1405"})); n != 0 {
+		t.Fatalf("a value with no property must not fold into a filter, got %d", n)
+	}
+
+	both := normalizedFilters(MetadataSearchRequest{
+		Property:      "tmdbid",
+		PropertyValue: "1405",
+		Filters:       []MetadataFilter{f("fileType", true, "video")},
+	})
+	if len(both) != 2 {
+		t.Fatalf("the legacy pair must be appended to explicit filters, got %d", len(both))
+	}
+}
+
+// The acceptance bar for routing the anchored path through the index: a
+// full-miss filtered sweep over a realistic corpus must stay in the same class
+// as the free-text branch (measured 10 ms over 19 622 live records), not the
+// legacy per-record Redis scan it replaces (measured 3.63 s over the same
+// corpus). Full-miss is the worst case — the loop cannot short-circuit on the
+// result limit, so every record is evaluated.
+//
+// Run: go test ./internal/api/ -bench BenchmarkFilterSweep -benchtime 10x
+func BenchmarkFilterSweep(b *testing.B) {
+	const records = 20000
+	corpus := make([]map[string]string, records)
+	for i := range corpus {
+		corpus[i] = map[string]string{
+			"title":                  "Some Release",
+			"fileType":               "video",
+			"videoType":              "tv",
+			"tmdbid":                 "1405",
+			"season":                 "2",
+			"genres/Action":          "true",
+			"genres/Drama":           "true",
+			"source/gateway:nyaa.si": "true",
+			"categories/TV/Anime":    "true",
+			"indexer":                "nyaa.si",
+			"fileName":               "some.release.s02e05.mkv",
+			"description/eng":        "text",
+			"poster":                 "bafy",
+			"sizeByte":               "123456789",
+			"contentKind":            "episode",
+			"anchoredBy/tmdb:1405":   "true",
+		}
+	}
+	// A miss on the identity field: the shape an id-anchored gateway query
+	// takes, and the one that must not degrade.
+	filters := []MetadataFilter{
+		f("tmdbid", true, "999999"),
+		f("fileType", true, "video"),
+		f("genres", true, "action"),
+	}
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		hits := 0
+		for _, fields := range corpus {
+			if recordMatchesFilters(fields, filters) {
+				hits++
+			}
+		}
+		if hits != 0 {
+			b.Fatalf("expected a full miss, got %d hits", hits)
+		}
+	}
+}

internal/api/search_index.go

@@ -3,6 +3,7 @@ package api
 import (
 	"log"
 	"net/http"
+	"sort"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -17,19 +18,46 @@ import (
 // batched bulk read (storage.GetSearchIndexTuples), off the request path.
 const searchIndexRefreshInterval = 60 * time.Second
 
+// searchIndexReconcileEvery is how many refresh ticks pass between full
+// rebuilds. Every other tick is incremental. 30 ticks × 60 s = a full
+// reconcile every 30 minutes — see runRefreshLoop for why one is kept at all.
+const searchIndexReconcileEvery = 30
+
 // searchIndex is an in-memory snapshot of every record's search haystack
-// (hashID + lowercased searchable fields), rebuilt periodically from Redis. It
+// (hashID + lowercased searchable fields), kept current from Redis. It exists
-// exists so POST /api/metadata/search matches in memory (string ops over a
+// so POST /api/metadata/search matches in memory (string ops over a slice)
-// slice) instead of doing a SCAN+MGET Redis round-trip per record — the latter
+// instead of doing a SCAN+MGET Redis round-trip per record — the latter took
-// took 40s+ over ~72k records and made a live parallel search path unusable.
+// 40s+ over ~72k records and made a live parallel search path unusable.
+//
+// # Two update paths, and why
+//
+// `refresh` rebuilds everything: a whole-keyspace SCAN, batched MGETs, and a
+// complete fresh copy. That is O(corpus) regardless of how much changed, and it
+// used to run every 60 s forever. Measured on a 19 622-record staging corpus
+// (2026-08-30): the loop accounted for ~45 % of ALL Redis CPU, and the Go side
+// held 783 MB for data Redis stores in 135 MB — largely the double copy.
+//
+// `refreshIncremental` re-reads only the records that changed, tracked by
+// storage's dirty set (search_dirty.go). Cost is O(change). It is the steady
+// state; the full rebuild runs once at startup (there is nothing to be
+// incremental against) and then only as an explicit repair.
+//
+// The distinction matters because meta-core is the platform's permanent,
+// additive store — every search hit on every gateway is retained — so a rebuild
+// priced against the whole corpus is a cost that only ever grows.
 type searchIndex struct {
 	mu sync.RWMutex
+	// byID is the authoritative content; tuples is a stable-order view of it
+	// rebuilt on each update. Map iteration order in Go is randomised, so
+	// serving a limited query straight off the map would return a different
+	// subset each call — the slice is what keeps results stable.
+	byID   map[string]storage.SearchTuple
 	tuples []storage.SearchTuple
 	ready  atomic.Bool
 }
 
 // snapshot returns the current tuples slice and whether the index has built at
-// least once. The refresh swaps in a fresh slice under the write lock (never
+// least once. Every update swaps in a fresh slice under the write lock (never
 // mutates in place), so the returned slice is safe to read lock-free.
 func (idx *searchIndex) snapshot() ([]storage.SearchTuple, bool) {
 	idx.mu.RLock()
@@ -37,7 +65,21 @@ func (idx *searchIndex) snapshot() ([]storage.SearchTuple, bool) {
 	return idx.tuples, idx.ready.Load()
 }
 
-// refresh rebuilds the index from Redis once (a batched bulk read).
+// rebuildViewLocked regenerates the stable-order slice from byID. Caller holds
+// the write lock.
+func (idx *searchIndex) rebuildViewLocked() {
+	view := make([]storage.SearchTuple, 0, len(idx.byID))
+	for _, t := range idx.byID {
+		view = append(view, t)
+	}
+	// Stable across rebuilds so a limited query returns a consistent page
+	// rather than a fresh random subset every interval.
+	sort.Slice(view, func(i, j int) bool { return view[i].HashID < view[j].HashID })
+	idx.tuples = view
+}
+
+// refresh rebuilds the whole index from Redis (a batched bulk read). Used for
+// the initial build and as an explicit repair — not the steady state.
 func (idx *searchIndex) refresh(stor *storage.Client) {
 	if stor == nil || !stor.IsConnected() {
 		return
@@ -47,27 +89,101 @@ func (idx *searchIndex) refresh(stor *storage.Client) {
 		log.Printf("[API] search index refresh failed: %v", err)
 		return
 	}
+	byID := make(map[string]storage.SearchTuple, len(tuples))
+	for _, t := range tuples {
+		byID[t.HashID] = t
+	}
 	idx.mu.Lock()
-	idx.tuples = tuples
+	idx.byID = byID
+	idx.rebuildViewLocked()
 	idx.mu.Unlock()
 	idx.ready.Store(true)
 }
 
-// runRefreshLoop builds the index immediately, then rebuilds on a ticker for the
+// refreshIncremental drains the dirty set and patches only those records.
-// process lifetime.
+// Returns whether more dirty entries remain, so a burst is caught up over
+// consecutive passes rather than one per interval.
+//
+// A record in the dirty set but absent from storage was deleted and is evicted
+// here — otherwise it would keep answering searches until the next full
+// rebuild. A batch that fails after the (destructive) drain is re-marked by
+// storage so it is retried rather than silently lost.
+func (idx *searchIndex) refreshIncremental(stor *storage.Client) (more bool) {
+	if stor == nil || !stor.IsConnected() {
+		return false
+	}
+	ids, more, err := stor.DrainDirty()
+	if err != nil {
+		log.Printf("[API] search index drain failed: %v", err)
+		return false
+	}
+	if len(ids) == 0 {
+		return false
+	}
+	tuples, gone, err := stor.GetSearchIndexTuplesFor(ids)
+	if err != nil {
+		stor.MarkDirty(ids...)
+		log.Printf("[API] incremental search index refresh failed: %v", err)
+		return false
+	}
+
+	idx.mu.Lock()
+	if idx.byID == nil {
+		idx.byID = make(map[string]storage.SearchTuple, len(tuples))
+	}
+	for _, t := range tuples {
+		idx.byID[t.HashID] = t
+	}
+	for _, id := range gone {
+		delete(idx.byID, id)
+	}
+	idx.rebuildViewLocked()
+	idx.mu.Unlock()
+
+	log.Printf("[API] search index: %d updated, %d evicted (%d records)", len(tuples), len(gone), len(idx.tuples))
+	return more
+}
+
+// runRefreshLoop builds the index once in full, then keeps it current from the
+// dirty set, with a periodic full reconcile as a safety net.
+//
+// The reconcile exists because a *missed* dirty mark is silent: no error, just
+// a record whose indexed copy quietly diverges from storage until something
+// forces a rebuild. Marking is spread across eight write paths plus anything
+// added later, and the cost of getting it wrong is invisible — so the index
+// should not depend on that coverage being perfect forever. Every
+// searchIndexReconcileEvery-th tick pays the old O(corpus) pass and repairs
+// whatever drifted.
+//
+// That still drops the full rebuild from every 60 s to every 30 min — a ~30×
+// reduction in the steady-state cost that measured at ~45 % of all Redis CPU —
+// while keeping the self-healing property that made the naive loop safe.
 func (idx *searchIndex) runRefreshLoop(stor *storage.Client) {
 	idx.refresh(stor)
 	ticker := time.NewTicker(searchIndexRefreshInterval)
 	defer ticker.Stop()
+	ticks := 0
 	for range ticker.C {
+		ticks++
+		if ticks%searchIndexReconcileEvery == 0 {
 			idx.refresh(stor)
+			continue
+		}
+		// Drain until caught up, so a burst larger than one batch does not take
+		// one interval per batch to land.
+		for idx.refreshIncremental(stor) {
+		}
 	}
 }
 
-// serveIndexedSearch answers a free-text (non-property) query from the in-memory
+// serveIndexedSearch answers a search from the in-memory index: a token-AND
-// index: token-AND match against each record's haystack (or a whole-query hashID
+// match against each record's haystack (or a whole-query hashID substring,
-// substring, preserving the legacy behaviour), then fetch full metadata for only
+// preserving the legacy behaviour) AND every structured filter, then returns
-// the <=limit matches. No Redis round-trip per scanned record.
+// the full metadata for the <=limit survivors. No Redis round-trip per scanned
+// record — matching and results both come from memory.
+//
+// This is the ONLY search path. Free text, filters, both, or neither all land
+// here; only the `hashId` exact-match branch in handleSearchMetadata bypasses it.
 func (s *Server) serveIndexedSearch(w http.ResponseWriter, req MetadataSearchRequest) {
 	tuples, ready := s.search.snapshot()
 	if !ready {
@@ -78,15 +194,20 @@ func (s *Server) serveIndexedSearch(w http.ResponseWriter, req MetadataSearchReq
 	}
 	tokens := strings.Fields(strings.ToLower(req.Query))
 	queryLower := strings.ToLower(req.Query)
+	filters := normalizedFilters(req)
 	results := make([]MetadataSearchResult, 0, req.Limit)
 	for _, t := range tuples {
 		if len(results) >= req.Limit {
 			break
 		}
-		if !matchAllTokens(t.Haystack, tokens) &&
+		if req.Query != "" &&
+			!matchAllTokens(t.Haystack, tokens) &&
 			!strings.Contains(strings.ToLower(t.HashID), queryLower) {
 			continue
 		}
+		if !recordMatchesFilters(t.Fields, filters) {
+			continue
+		}
 		// Full metadata is cached in the index — return it straight from memory,
 		// no Redis round-trip per result.
 		results = append(results, MetadataSearchResult{HashID: t.HashID, Metadata: t.Fields})
@@ -108,3 +229,114 @@ func matchAllTokens(haystack string, tokens []string) bool {
 	}
 	return true
 }
+
+// normalizedFilters returns the request's structured filters with the legacy
+// Property/PropertyValue pair folded in as one more entry.
+//
+// The legacy pair keeps Exact=false so its long-standing substring semantics
+// are unchanged for existing callers; new callers pass Filters and choose.
+func normalizedFilters(req MetadataSearchRequest) []MetadataFilter {
+	if req.Property == "" || req.PropertyValue == "" {
+		return req.Filters
+	}
+	out := make([]MetadataFilter, 0, len(req.Filters)+1)
+	out = append(out, req.Filters...)
+	return append(out, MetadataFilter{
+		Property: req.Property,
+		Values:   []string{req.PropertyValue},
+	})
+}
+
+// recordMatchesFilters reports whether fields satisfies every filter (AND).
+func recordMatchesFilters(fields map[string]string, filters []MetadataFilter) bool {
+	for i := range filters {
+		if !recordMatchesFilter(fields, &filters[i]) {
+			return false
+		}
+	}
+	return true
+}
+
+// recordMatchesFilter reports whether fields satisfies one filter (OR within
+// its values), probing BOTH storage shapes a field can take:
+//
+//   - a flat scalar/csv-set field — `fileType = "video"`, `videoType = "tv,anime"`;
+//   - a key-set member — `genres/Action = "true"`, `source/gateway:nyaa.si = "true"`
+//     (METADATA_KEYS "How the store is shaped").
+//
+// Probing both is what lets one filter shape serve the whole vocabulary. The
+// gateway needs a `genres:action` filter to find a record whose genre lives in
+// the key `genres/Action`, and a `fileType:video` filter to find one whose value
+// lives in the field `fileType` — without meta-core knowing which fields are
+// key-sets. It also means this stays a SUPERSET of the gateway's own
+// `record_matches`, which is the contract: meta-core pre-filters, the gateway
+// re-filters authoritatively.
+//
+// A filter with no usable value constrains nothing (matches). A filter whose
+// field is absent fails closed, matching `record_matches`.
+func recordMatchesFilter(fields map[string]string, f *MetadataFilter) bool {
+	values := make([]string, 0, len(f.Values))
+	for _, v := range f.Values {
+		if v = strings.TrimSpace(v); v != "" {
+			values = append(values, v)
+		}
+	}
+	if f.Property == "" || len(values) == 0 {
+		return true
+	}
+
+	// Key-set shape: `<property>/<value>` present and truthy. Try the exact
+	// key first — that hits whenever the caller's casing matches what was
+	// written, which is the common case and costs one map probe.
+	for _, v := range values {
+		if isTruthyMember(fields[f.Property+"/"+v]) {
+			return true
+		}
+	}
+	// Members are written verbatim (`genres/Action`) while query values arrive
+	// lowercased, so fall back to one case-insensitive sweep. Single pass over
+	// the record's fields for ALL values, not one pass per value.
+	wanted := make(map[string]struct{}, len(values))
+	for _, v := range values {
+		wanted[strings.ToLower(v)] = struct{}{}
+	}
+	prefix := strings.ToLower(f.Property) + "/"
+	for k, val := range fields {
+		if len(k) <= len(prefix) || !strings.EqualFold(k[:len(prefix)], prefix) {
+			continue
+		}
+		if _, ok := wanted[strings.ToLower(k[len(prefix):])]; ok && isTruthyMember(val) {
+			return true
+		}
+	}
+
+	// Flat shape: the field's own value, split on `,` for csv-set fields.
+	fieldValue, ok := fields[f.Property]
+	if !ok {
+		return false
+	}
+	for _, piece := range strings.Split(fieldValue, ",") {
+		piece = strings.TrimSpace(piece)
+		if piece == "" {
+			continue
+		}
+		for _, v := range values {
+			if f.Exact {
+				if strings.EqualFold(piece, v) {
+					return true
+				}
+			} else if strings.Contains(strings.ToLower(piece), strings.ToLower(v)) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// isTruthyMember reports whether a key-set member's value asserts membership.
+// Mirrors the gateway's `is_truthy_member`: presence with a non-empty,
+// non-"false"/"0" value.
+func isTruthyMember(v string) bool {
+	v = strings.TrimSpace(strings.ToLower(v))
+	return v != "" && v != "false" && v != "0"
+}

internal/api/server.go

@@ -9,10 +9,10 @@ import (
 
 	"github.com/gorilla/mux"
 	"github.com/metazla/meta-core/internal/config"
-	"github.com/metazla/meta-core/internal/discovery"
 	"github.com/metazla/meta-core/internal/events"
 	"github.com/metazla/meta-core/internal/identity"
 	"github.com/metazla/meta-core/internal/leader"
+	"github.com/metazla/meta-core/internal/meshdisco"
 	"github.com/metazla/meta-core/internal/mounts"
 	"github.com/metazla/meta-core/internal/schema"
 	"github.com/metazla/meta-core/internal/storage"
@@ -25,8 +25,6 @@ import (
 type Server struct {
 	config            *config.Config
 	leaderProvider    *leader.LeaderInfoProvider
-	discovery         *discovery.Service
-	cleaner           *discovery.Cleaner
 	storage           *storage.Client
 	mountsManager     *mounts.Manager
 	mountsHandlers    *mounts.Handlers
@@ -42,26 +40,40 @@ type Server struct {
 	schemaIndexer     *schema.Indexer
 	webdavHandler     *webdav.Handler
 	search            *searchIndex
+	// challenges backs proof-of-possession on reveal/delete. In-process, so a
+	// restart invalidates the ones in flight — see identity/challenge.go.
+	challenges *identity.ChallengeStore
+	// mesh is the UDP discovery node (meta-discovery v1). nil when discovery
+	// is disabled or failed to bind, in which case /api/neighbors reports an
+	// empty list rather than erroring — a dashboard nav is decoration and
+	// must not take the API down with it.
+	mesh   *meshdisco.Node
 	router *mux.Router
 	server *http.Server
+	// stats caches the keyspace-walk half of GET /api/stats so a polling
+	// dashboard never puts a multi-second Redis walk on the request path.
+	stats *statsCache
+}
+
+// SetMeshNode attaches the UDP discovery node. Separate from NewServer so the
+// server's constructor signature (and its tests) stay untouched.
+func (s *Server) SetMeshNode(n *meshdisco.Node) {
+	s.mesh = n
 }
 
 // NewServer creates a new API server
 func NewServer(
 	cfg *config.Config,
 	leaderProvider *leader.LeaderInfoProvider,
-	disc *discovery.Service,
-	cleaner *discovery.Cleaner,
 	stor *storage.Client,
 ) *Server {
 	s := &Server{
 		config:         cfg,
 		leaderProvider: leaderProvider,
-		discovery:      disc,
-		cleaner:        cleaner,
 		storage:        stor,
 		search:         &searchIndex{},
 		router:         mux.NewRouter(),
+		stats:          &statsCache{},
 	}
 
 	// Initialize file watcher/scanner and dispatcher
@@ -139,6 +151,8 @@ func NewServer(
 	// Initialize WebDAV handler (caching is handled by nginx proxy_cache)
 	s.webdavHandler = webdav.NewHandler(cfg)
 
+	s.challenges = identity.NewChallengeStore()
+
 	// One-time migration: fold a pre-multi-account identity.json into the
 	// per-account keystore so existing single-identity hosts keep their uid.
 	if migrated, err := identity.MigrateLegacy(cfg.IdentityFilePath(), cfg.IdentityAccountsDir()); err != nil {
@@ -159,6 +173,10 @@ func (s *Server) setupRoutes() {
 	s.router.HandleFunc("/leader", s.handleLeader).Methods("GET")
 	s.router.HandleFunc("/urls", s.handleURLs).Methods("GET")
 
+	// Dashboard headline counters in one request. Cheap half live, keyspace
+	// walks served from a background-refreshed cache — see stats.go.
+	s.router.HandleFunc("/api/stats", s.handleStats).Methods("GET")
+
 	// Metadata Editor API routes (must be before /meta/{hash} routes)
 	s.router.HandleFunc("/api/metadata/hash-ids", s.handleGetHashIds).Methods("GET")
 	s.router.HandleFunc("/api/metadata/list", s.handleListMetadata).Methods("GET")
@@ -170,6 +188,7 @@ func (s *Server) setupRoutes() {
 	// at the perimeter — do NOT add to nginx-hash-lock unauth bypass.
 	s.router.HandleFunc("/api/identity", s.handleIdentityGet).Methods("GET")
 	s.router.HandleFunc("/api/identity/accounts", s.handleIdentityAccounts).Methods("GET")
+	s.router.HandleFunc("/api/identity/challenge", s.handleIdentityChallenge).Methods("POST")
 	s.router.HandleFunc("/api/identity/generate", s.handleIdentityGenerate).Methods("POST")
 	s.router.HandleFunc("/api/identity/import", s.handleIdentityImport).Methods("POST")
 	s.router.HandleFunc("/api/identity/reveal", s.handleIdentityReveal).Methods("POST")
@@ -210,8 +229,11 @@ func (s *Server) setupRoutes() {
 	s.router.HandleFunc("/api/udl/records", s.handleUDLRecordsPut).Methods("PUT")
 	s.router.HandleFunc("/api/udl/user/{uid}/key/{key}", s.handleUDLUserKey).Methods("GET")
 	s.router.HandleFunc("/api/udl/user/{uid}/cid/{cid}", s.handleUDLUserCid).Methods("GET")
+	s.router.HandleFunc("/api/udl/user/{uid}/all", s.handleUDLUserAll).Methods("GET")
+	s.router.HandleFunc("/api/udl/user/{uid}/count", s.handleUDLUserCount).Methods("GET")
 	s.router.HandleFunc("/api/udl/cid/{cid}/users", s.handleUDLCidUsers).Methods("GET")
 	s.router.HandleFunc("/api/udl/cid/{cid}/aggregate", s.handleUDLAggregate).Methods("GET")
+	s.router.HandleFunc("/api/udl/users/stats", s.handleUDLUserStats).Methods("GET")
 
 	// Metadata operations - base endpoints
 	s.router.HandleFunc("/meta/{hash}", s.handleGetMeta).Methods("GET")
@@ -236,6 +258,14 @@ func (s *Server) setupRoutes() {
 	s.router.HandleFunc("/api/file/{cid}/info", s.handleGetFileByCIDInfo).Methods("GET")
 	s.router.HandleFunc("/file/{cid}", s.handleGetFileByCID).Methods("GET")
 	s.router.HandleFunc("/file/cid", s.handleComputeFileCID).Methods("POST")
+	// Register one file under /files/plugin by midhash — the watcher's
+	// mint + alias + file:events path for a single file. Registered
+	// unconditionally: it exists for boxes whose watcher is OFF.
+	s.router.HandleFunc("/api/files/register", s.handleRegisterFile).Methods("POST")
+	// File-backed roots (filePath+sizeByte+mtimeNano) with sizes, batched
+	// server-side, so clients answer "how many files, how big" without one
+	// read per hashId. ?summary=1 returns only {count, totalSize}.
+	s.router.HandleFunc("/api/files/tuples", s.handleGetFileTuples).Methods("GET")
 
 	// Public metadata-by-CID resolver. Reverse-index lookup → full document.
 	// Auth-bypassed alongside /api/file/{cid} so meta-share peers can query
@@ -246,6 +276,13 @@ func (s *Server) setupRoutes() {
 	// (the dual-root pattern caused by historical writes that bypassed CID
 	// resolution).
 	s.router.HandleFunc("/api/admin/migrate-dual-roots", s.handleMigrateDualRoots).Methods("POST")
+	// One-shot vocabulary sweep: domain film|tv → screen, workForm backfill
+	// (METADATA_KEYS.md §14.17). Idempotent.
+	s.router.HandleFunc("/api/admin/migrate-domain-screen", s.handleMigrateDomainScreen).Methods("POST")
+	s.router.HandleFunc("/api/admin/migrate-user-cids", s.handleMigrateUserCids).Methods("POST")
+	// One-shot sweep of query echoes on literature cards (meta-read
+	// reading-model.md §7). Dry-run unless ?apply=true. Idempotent.
+	s.router.HandleFunc("/api/admin/sweep-literature-echoes", s.handleSweepLiteratureEchoes).Methods("POST")
 
 	// SSE event streams. Mediated mirror of the Redis Streams; consumers
 	// reach them over HTTP instead of touching Redis directly. Auth-bypass
@@ -254,12 +291,10 @@ func (s *Server) setupRoutes() {
 	s.router.HandleFunc("/api/events/files", s.handleEventsFiles).Methods("GET")
 	s.router.HandleFunc("/api/events/meta", s.handleEventsMeta).Methods("GET")
 
-	// Service discovery
+	// meta-discovery v1: neighbours heard over UDP. Supersedes /api/services,
-	// Both /services and /api/services are supported for consistency with other services
+	// which is still served above while consumers migrate.
-	s.router.HandleFunc("/services", s.handleListServices).Methods("GET")
+	s.router.HandleFunc("/neighbors", s.handleListNeighbors).Methods("GET")
-	s.router.HandleFunc("/api/services", s.handleListServices).Methods("GET")
+	s.router.HandleFunc("/api/neighbors", s.handleListNeighbors).Methods("GET")
-	s.router.HandleFunc("/services/cleanup/stats", s.handleCleanupStats).Methods("GET")
-	s.router.HandleFunc("/services/{name}", s.handleGetService).Methods("GET")
 
 	// Mount management routes (if manager initialized)
 	if s.mountsHandlers != nil {

internal/api/stats.go

@@ -0,0 +1,164 @@
+package api
+
+import (
+	"log"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/metazla/meta-core/internal/identity"
+)
+
+// statsSweepTTL is how long a keyspace-walk result stays good. The walk is
+// never on the request path (see statsCache), so this only controls how stale
+// the library tiles may look, not how slow the endpoint is.
+const statsSweepTTL = 60 * time.Second
+
+// fileStatsJSON is the file-backed half of the library: the roots that carry
+// filePath+sizeByte+mtimeNano. Gateway / cid-rooted records have no file on
+// disk and are counted in Records, not here — the gap between the two numbers
+// is exactly "metadata we hold for files we do not have".
+type fileStatsJSON struct {
+	Count     int   `json:"count"`
+	TotalSize int64 `json:"totalSize"`
+}
+
+// StatsResponse is the body of GET /api/stats — every headline number the
+// dashboard shows, in one request.
+//
+// Deliberately split by cost. Records/RedisKeys/RedisMemory/Identities are
+// O(1) commands (SCARD, DBSIZE, INFO) plus a directory listing, recomputed on
+// every call. Files and UDLUsers need a keyspace walk — ~0.5s for the file
+// tuples and ~3s for the UDL SCAN on an 88k-record box — so they are served
+// from a background-refreshed cache and are null until the first sweep lands.
+type StatsResponse struct {
+	Records     int64          `json:"records"`
+	RedisKeys   int64          `json:"redisKeys"`
+	RedisMemory string         `json:"redisMemory"`
+	Identities  int            `json:"identities"`
+	Files       *fileStatsJSON `json:"files"`
+	UDLUsers    *int           `json:"udlUsers"`
+	// SweptAt is when the cached half was computed (unix ms), 0 if never.
+	SweptAt int64 `json:"sweptAt"`
+	// Sweeping reports that a refresh is in flight, so the UI can show the
+	// cached numbers as provisional instead of pretending they are live.
+	Sweeping bool `json:"sweeping"`
+}
+
+// statsCache holds the expensive half of /api/stats.
+//
+// Why a cache and not just "compute it": the dashboard polls. A 3s Redis walk
+// per tick, per open tab, is a self-inflicted outage on a box that is also
+// serving playback — the same shape as meta-sort's /api/stats full sweep. So
+// the handler NEVER waits on a walk: it returns whatever the last sweep
+// produced and kicks off a new one if the old one is stale. `running` makes
+// that single-flight, so ten tabs cost one walk.
+type statsCache struct {
+	mu       sync.Mutex
+	files    *fileStatsJSON
+	udlUsers *int
+	sweptAt  time.Time
+	running  bool
+}
+
+// snapshot returns the cached values and whether a refresh is in flight.
+func (c *statsCache) snapshot() (*fileStatsJSON, *int, time.Time, bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	return c.files, c.udlUsers, c.sweptAt, c.running
+}
+
+// refreshIfStale starts a background sweep unless one is already running or
+// the last result is still fresh. Returns true if it started one.
+func (c *statsCache) refreshIfStale(sweep func() (*fileStatsJSON, *int)) bool {
+	c.mu.Lock()
+	if c.running || time.Since(c.sweptAt) < statsSweepTTL {
+		c.mu.Unlock()
+		return false
+	}
+	c.running = true
+	c.mu.Unlock()
+
+	go func() {
+		files, udl := sweep()
+		c.mu.Lock()
+		defer c.mu.Unlock()
+		c.running = false
+		// A failed sweep leaves the previous numbers in place rather than
+		// blanking the tiles; sweptAt still advances so a hard-failing walk
+		// (Redis down) does not spin once per poll.
+		c.sweptAt = time.Now()
+		if files != nil {
+			c.files = files
+		}
+		if udl != nil {
+			c.udlUsers = udl
+		}
+	}()
+	return true
+}
+
+// handleStats handles GET /api/stats.
+func (s *Server) handleStats(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+
+	resp := StatsResponse{}
+
+	if n, err := s.storage.CountRoots(); err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	} else {
+		resp.Records = n
+	}
+	if n, err := s.storage.CountKeys(); err == nil {
+		resp.RedisKeys = n
+	}
+	if mem, err := s.storage.GetMemoryInfo(); err == nil {
+		resp.RedisMemory = mem
+	} else {
+		resp.RedisMemory = "N/A"
+	}
+	if list, err := identity.List(s.config.IdentityAccountsDir()); err == nil {
+		resp.Identities = len(list)
+	}
+
+	s.stats.refreshIfStale(s.sweepStats)
+	files, udl, sweptAt, sweeping := s.stats.snapshot()
+	resp.Files = files
+	resp.UDLUsers = udl
+	resp.Sweeping = sweeping
+	if !sweptAt.IsZero() {
+		resp.SweptAt = sweptAt.UnixMilli()
+	}
+
+	writeJSON(w, http.StatusOK, resp)
+}
+
+// sweepStats runs the two keyspace walks behind the cached tiles. Called off
+// the request path only. A failing half returns nil so the other half still
+// lands.
+func (s *Server) sweepStats() (*fileStatsJSON, *int) {
+	var files *fileStatsJSON
+	if tuples, err := s.storage.GetTuplesForAllFiles(); err != nil {
+		log.Printf("[API] stats: file tuple sweep failed: %v", err)
+	} else {
+		fs := fileStatsJSON{Count: len(tuples)}
+		for _, t := range tuples {
+			fs.TotalSize += t.Size
+		}
+		files = &fs
+	}
+
+	var udl *int
+	if stats, err := s.storage.UDLAllUserStats(); err != nil {
+		log.Printf("[API] stats: UDL user sweep failed: %v", err)
+	} else {
+		n := len(stats)
+		udl = &n
+	}
+
+	return files, udl
+}

internal/api/udl.go

@@ -13,9 +13,11 @@ import (
 	"encoding/json"
 	"math"
 	"net/http"
+	"strconv"
 	"strings"
 
 	"github.com/gorilla/mux"
+	"github.com/metazla/meta-core/internal/storage"
 )
 
 // UDLPutRequest is the body of PUT /api/udl/record.
@@ -270,6 +272,75 @@ func (s *Server) handleUDLUserCid(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, map[string]interface{}{"entries": entries})
 }
 
+// handleUDLUserAll handles GET /api/udl/user/{uid}/all?after=<cid>&limit=<n>
+// — every record a uid owns, for cross-instance profile recovery.
+//
+// The other user-scoped reads answer a question with one coordinate already
+// known. Recovery knows only the uid: a box that has just imported a secret key
+// has no idea which cids or keys the profile ever touched, so it needs the
+// whole set or it gets nothing.
+//
+// Paged on a cid boundary — `nextCid` empty means the export is complete. The
+// response is opaque signed records, exactly as stored; whoever consumes it is
+// responsible for verifying each one before trusting it (meta-core has never
+// held the account key and cannot verify on anyone's behalf).
+func (s *Server) handleUDLUserAll(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+	uid := mux.Vars(r)["uid"]
+	if uid == "" {
+		writeError(w, http.StatusBadRequest, "uid is required")
+		return
+	}
+	limit := maxUDLBatch
+	if v := r.URL.Query().Get("limit"); v != "" {
+		n, err := strconv.Atoi(v)
+		if err != nil || n <= 0 {
+			writeError(w, http.StatusBadRequest, "limit must be a positive integer")
+			return
+		}
+		if n < limit {
+			limit = n
+		}
+	}
+	entries, nextCid, err := s.storage.UDLAllForUser(uid, r.URL.Query().Get("after"), limit)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]interface{}{
+		"entries": entries,
+		"nextCid": nextCid,
+	})
+}
+
+// handleUDLUserCount handles GET /api/udl/user/{uid}/count — how many cids a
+// uid holds records for.
+//
+// Exists so a gateway mirror can enforce a per-profile quota without walking
+// anything: 32 random bytes are a valid uid, so an unbounded mirror is a
+// disk-fill DoS that needs no account. A quota check that itself cost a scan
+// would just move the denial of service one layer up.
+func (s *Server) handleUDLUserCount(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeError(w, http.StatusServiceUnavailable, "storage not connected")
+		return
+	}
+	uid := mux.Vars(r)["uid"]
+	if uid == "" {
+		writeError(w, http.StatusBadRequest, "uid is required")
+		return
+	}
+	n, err := s.storage.UDLCountUserCids(uid)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]interface{}{"cids": n})
+}
+
 // handleUDLCidUsers handles GET /api/udl/cid/{cid}/users (uids_for_cid).
 func (s *Server) handleUDLCidUsers(w http.ResponseWriter, r *http.Request) {
 	if !s.storage.IsConnected() {
@@ -349,3 +420,35 @@ func aggregatePublicValues(key string, values []string) UDLAggregate {
 	}
 	return agg
 }
+
+// udlUserStatsResponse is the shape of GET /api/udl/users/stats.
+type udlUserStatsResponse struct {
+	// Users maps uid -> counts. Accounts holding nothing are absent rather than
+	// present with zeroes; a caller rendering a list treats "missing" as 0.
+	Users map[string]storage.UDLUserStats `json:"users"`
+}
+
+// handleUDLUserStats handles GET /api/udl/users/stats — how much every account
+// holds, in one keyspace walk.
+//
+// Bulk rather than per-uid because the only caller is the accounts page, which
+// needs a number for every row: the counts come from a SCAN (there is no
+// per-user cid index — see storage/udl_admin.go), and MATCH filters without
+// indexing, so N per-uid calls would walk the whole keyspace N times.
+//
+// Deliberately not on the critical path of anything. It is an admin read whose
+// cost grows with the keyspace, so callers should fetch it after rendering,
+// never before.
+func (s *Server) handleUDLUserStats(w http.ResponseWriter, r *http.Request) {
+	if !s.storage.IsConnected() {
+		writeErrorSlug(w, http.StatusServiceUnavailable, "storage_unavailable",
+			"storage not connected", true)
+		return
+	}
+	stats, err := s.storage.UDLAllUserStats()
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, err.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, udlUserStatsResponse{Users: stats})
+}

internal/cid/card.go

@@ -0,0 +1,92 @@
+package cid
+
+import (
+	"encoding/base32"
+	"encoding/binary"
+	"fmt"
+	"strings"
+	"unicode/utf8"
+)
+
+// DecodeCard recovers the (source, id) pair a card locator (CodeCard, 0x1007)
+// wraps. Wire form:
+//
+//	0x01 ‖ varint(0x1007) ‖ 0x00 (identity mh) ‖ varint(len(digest)) ‖ digest
+//	digest = varint(len(source)) ‖ source ‖ id        (both UTF-8)
+//
+// Decode stops at the multihash code because ranking needs nothing past it;
+// reading *which work* a card addresses needs the digest too, so this is the
+// one place in Go that walks the whole thing.
+//
+// ⚠ Mirror of meta-read `card_cid::decode` and of meta-feeder-sdk
+// `compute_card_cid`. The vectors in card_test.go are pinned literals copied
+// from meta-read, not round-trips, so a drift on either side fails a test
+// instead of silently reading a different work out of the same CID.
+//
+// Identity multihash only: a 0x1007 CID carrying any other multihash is not
+// something anyone mints, and reading its digest as (source, id) would be
+// reading hash bytes as text. Bytes past the declared digest length are
+// ignored, as meta-read does.
+func DecodeCard(cidStr string) (source, id string, err error) {
+	if len(cidStr) < 2 || cidStr[0] != 'b' {
+		return "", "", fmt.Errorf("cid %q: not a multibase base32 CIDv1", cidStr)
+	}
+	raw, err := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString(strings.ToUpper(cidStr[1:]))
+	if err != nil {
+		return "", "", fmt.Errorf("cid %q: base32 decode: %w", cidStr, err)
+	}
+
+	next := func(buf []byte, what string) (uint64, []byte, error) {
+		v, n := binary.Uvarint(buf)
+		if n <= 0 {
+			return 0, nil, fmt.Errorf("cid %q: bad %s varint", cidStr, what)
+		}
+		return v, buf[n:], nil
+	}
+
+	version, raw, err := next(raw, "version")
+	if err != nil {
+		return "", "", err
+	}
+	if version != 1 {
+		return "", "", fmt.Errorf("cid %q: unsupported CID version %d", cidStr, version)
+	}
+	codec, raw, err := next(raw, "codec")
+	if err != nil {
+		return "", "", err
+	}
+	if codec != CodeCard {
+		return "", "", fmt.Errorf("cid %q: codec 0x%x is not a card locator", cidStr, codec)
+	}
+	mh, raw, err := next(raw, "multihash-code")
+	if err != nil {
+		return "", "", err
+	}
+	if mh != 0 {
+		return "", "", fmt.Errorf("cid %q: card locator with non-identity multihash 0x%x", cidStr, mh)
+	}
+	digestLen, raw, err := next(raw, "digest-length")
+	if err != nil {
+		return "", "", err
+	}
+	if digestLen > uint64(len(raw)) {
+		return "", "", fmt.Errorf("cid %q: digest truncated", cidStr)
+	}
+	digest := raw[:digestLen]
+
+	sourceLen, rest, err := next(digest, "source-length")
+	if err != nil {
+		return "", "", err
+	}
+	if sourceLen > uint64(len(rest)) {
+		return "", "", fmt.Errorf("cid %q: source truncated", cidStr)
+	}
+	source, id = string(rest[:sourceLen]), string(rest[sourceLen:])
+	if source == "" || id == "" {
+		return "", "", fmt.Errorf("cid %q: empty source or id", cidStr)
+	}
+	if !utf8.ValidString(source) || !utf8.ValidString(id) {
+		return "", "", fmt.Errorf("cid %q: source or id is not UTF-8", cidStr)
+	}
+	return source, id, nil
+}

internal/cid/card_test.go

@@ -0,0 +1,71 @@
+package cid
+
+import (
+	"encoding/base32"
+	"encoding/binary"
+	"strings"
+	"testing"
+)
+
+// Pinned from meta-read `src/card_cid.rs` / meta-feeder-sdk `compute_card_cid`
+// — literals, not round-trips (see DecodeCard).
+const (
+	goldenAnilistCard  = "bagdsaaaua5qw42lmnfzxi3lbnztwcorrga2tonzy"
+	goldenMangadexCard = "bagdsaabybrwwc3thmfsgk6bon5zgol3nmfxgoyjpmiygenzsgftgmlldgm4dqljugq4dmllbmeygmlldgjrdaytcgmzdcnjrgi"
+)
+
+// wireCID builds a CIDv1 from raw parts so the negative cases below can vary
+// one field at a time.
+func wireCID(codec, mh uint64, digest []byte) string {
+	buf := []byte{0x01}
+	buf = binary.AppendUvarint(buf, codec)
+	buf = binary.AppendUvarint(buf, mh)
+	buf = binary.AppendUvarint(buf, uint64(len(digest)))
+	buf = append(buf, digest...)
+	return "b" + strings.ToLower(base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(buf))
+}
+
+func cardDigest(source, id string) []byte {
+	d := binary.AppendUvarint(nil, uint64(len(source)))
+	d = append(d, source...)
+	return append(d, id...)
+}
+
+func TestDecodeCard_GoldenVectors(t *testing.T) {
+	for _, tc := range []struct {
+		cid, source, id string
+	}{
+		{goldenAnilistCard, "anilist", "manga:105778"},
+		{goldenMangadexCard, "mangadex.org", "/manga/b0b721ff-c388-4486-aa0f-c2b0bb321512"},
+	} {
+		source, id, err := DecodeCard(tc.cid)
+		if err != nil {
+			t.Fatalf("DecodeCard(%s): %v", tc.cid, err)
+		}
+		if source != tc.source || id != tc.id {
+			t.Errorf("DecodeCard(%s) = (%q, %q), want (%q, %q)", tc.cid, source, id, tc.source, tc.id)
+		}
+		// The test encoder must agree with the pinned literal, or the negative
+		// cases below are testing a different wire format.
+		if got := wireCID(CodeCard, 0, cardDigest(tc.source, tc.id)); got != tc.cid {
+			t.Errorf("wireCID(%q, %q) = %s, want %s", tc.source, tc.id, got, tc.cid)
+		}
+	}
+}
+
+func TestDecodeCard_RejectsEverythingElse(t *testing.T) {
+	for name, s := range map[string]string{
+		"url locator codec":      wireCID(CodeURL, 0, cardDigest("anilist", "1")),
+		"non-identity multihash": wireCID(CodeCard, CodeSha256, cardDigest("anilist", "1")),
+		"empty id":               wireCID(CodeCard, 0, cardDigest("anilist", "")),
+		"source past digest":     wireCID(CodeCard, 0, []byte{0x20, 'a'}),
+		"not a CID":              "title:berserk",
+		"CIDv0":                  "QmYwAPJzv5CZsnA625s3Xf2nemtYgPpHdWEz79ojWnPbdG",
+		"truncated":              goldenAnilistCard[:12],
+		"empty":                  "",
+	} {
+		if source, id, err := DecodeCard(s); err == nil {
+			t.Errorf("%s: DecodeCard(%q) = (%q, %q), want error", name, s, source, id)
+		}
+	}
+}

internal/cid/cid-rank-vectors.json

@@ -22,7 +22,7 @@
     "25": "nzb-posting - content-derived (Message-ID set digest), but not itself fetchable",
     "20": "BitTorrent infohashes - swarm interop",
     "10": "midhash256 - the record address",
-    "5": "opaque locators (nzb-release, url, card) - never outrank a real digest",
+    "5": "opaque locators (nzb-release, url, card, yt-video, ext-play) - never outrank a real digest",
     "0": "weak/unknown digests, unparseable input"
   },
   "tieBreak": "lexicographically smaller cid wins",
@@ -116,6 +116,24 @@
       "rank": 5,
       "note": "codec 0x1007 + IDENTITY multihash 0x00, digest = varint(len(source)) || source || id — here (\"tmdb\",\"tv:95479\"). Same codec-slot rule as nzb-release/url: match on the CODEC, never the mh. The limit case of the family — the only CID in MetaMesh with NO bytes behind it anywhere, ever: it addresses a *work* (a series, a film), not a file, so the byte path 404s by design and bitswap never offers it (seeding is gated on sha2-256). Tier 5 is load-bearing for the planned cross-source merge: one card record may carry BOTH a TMDB and a MyAnimeList locator, and if a real card body is ever added (see card-tier-search.md §4.3) its sha2-256 must win the canonical election over both locators without any addressing change. Ranking it 0 instead would still lose to a digest, but would put the implementations back out of agreement — which is the exact failure this fixture exists to prevent."
     },
+    {
+      "name": "yt-video-locator",
+      "cid": "bagecaaarav3gszdfn42ein3vgvfumn2tka4a",
+      "rank": 5,
+      "note": "codec 0x1008 + IDENTITY multihash 0x00, digest = varint(len(kind)) || kind || id — here (\"video\",\"4D7u5KF7SP8\"). DELEGATED PLAYBACK: the limit case beyond card. A card addresses a work with no bytes anywhere; this addresses a *rendition* whose bytes exist but are permanently someone else's — an external player renders it, nothing is transported, seeded or content-addressed. Framing is byte-identical to card (0x1007) on purpose, so each implementation extends the parser it already wrote. Same codec-slot rule: match on the CODEC, never the mh (identity 0x00 would fall through and score 0). Tier 5 is load-bearing for the on-ramp: a delegated reference and a real archived copy can sit on ONE record, and that sha2-256 must win the canonical election over this locator with no addressing change. NOTE the byte path must REFUSE this (400), not 404 — see docs/cid-formats.md §7.4."
+    },
+    {
+      "name": "ext-play-locator",
+      "cid": "bagesaabenb2hi4dthixs6zlymfwxa3dffzrgc3temnqw24bomnxw2l3bnrrhk3jppa",
+      "rank": 5,
+      "note": "codec 0x1009 + IDENTITY multihash 0x00, digest = the verbatim UTF-8 URL. WIRE-IDENTICAL to url (0x1006) apart from the codec, and that difference is the entire contract: 0x1006 means 'fetch these bytes once and seed them', 0x1009 means 'open this in a browser, there are no bytes for us'. A decoder that matched on SHAPE rather than on the codec slot would see an identity multihash wrapping an http(s) URL, take the 0x1006 path, fetch a watch/Bandcamp page, chunk it, seed the HTML and link that content CID onto the record AS THE FILE — the MSR1 poisoning shape, except permanent and replicated. Same tier/reasoning as the rest of the locator family."
+    },
+    {
+      "name": "provider-file-locator",
+      "cid": "bagfcaaa2bvxxazloon2we5djorwgk43gnfwgkorxga3dcobtgq",
+      "rank": 5,
+      "note": "codec 0x100A + IDENTITY multihash 0x00, digest = varint(len(source)) || source || id - here (\"opensubtitles\",\"file:7061834\"). The GENERIC fetchable locator: one codec for every provider whose bytes are fetched the same way; the provider is inside the digest. Framing byte-identical to card (0x1007), but the byte path RESOLVES it (via source's fetch tier) instead of 404ing. Same codec-slot rule as the rest of the family: match on the CODEC, never the mh (identity 0x00 would fall through and score 0). Tier 5: once the fetched bytes' sha2-256 is linked onto the record it wins the canonical election with no addressing change."
+    },
     {
       "name": "sha1",
       "cid": "baeircff3eqvxxaqqot2lt242stkdtk3gq4c2vra",

internal/cid/rank.go

@@ -58,6 +58,31 @@ const (
 	// one record, and a real digest added later still wins the election.
 	CodeCard = 0x1007 // custom — identity-multihash CID wrapping a card (work) id
 
+	// CodeYtVideo and CodeExtPlay are the DELEGATED-PLAYBACK locators — the
+	// limit case beyond CodeCard. A card addresses a work with no bytes
+	// anywhere; these address a *rendition* whose bytes exist but are
+	// permanently someone else's: an external player renders the media, nothing
+	// is transported, seeded or content-addressed.
+	//
+	// They rank on the CODEC like the rest of the family — their multihash is
+	// identity (0x00), so a rank that dispatched on the multihash would see 0x00,
+	// fall through and silently score 0. That is the exact drift that once made
+	// meta-share and meta-search elect different canonical CIDs for one record.
+	//
+	// Tier 5 is also what keeps the on-ramp safe: a delegated reference and a
+	// real CID can sit on one record, and if the media is ever archived to the
+	// mesh its sha2-256 wins the canonical election with no addressing change.
+	CodeYtVideo = 0x1008 // custom — identity-multihash CID wrapping a YouTube (kind, id)
+	CodeExtPlay = 0x1009 // custom — identity-multihash CID wrapping a URL to OPEN, never fetch
+
+	// CodeProviderFile is the FETCHABLE twin of CodeExtPlay: a provider-held
+	// file addressed as varint(len(source))‖source‖id — ("opensubtitles",
+	// "file:7061834"). Framing is byte-identical to CodeCard; only the byte
+	// path differs (it redeems the id through that source's feeder instead of
+	// 404ing). Same codec-slot rule and same tier: once the fetched bytes'
+	// sha2-256 is linked onto the record it wins with no addressing change.
+	CodeProviderFile = 0x100A // custom — identity-multihash CID wrapping a (source, id) provider file
+
 	// CodeNzbPosting is the INVERSE trap of the two above: its multihash is a
 	// REAL sha2-256 digest (over the normalised, sorted article Message-ID
 	// set of a Usenet posting we scanned ourselves — never a locator, no
@@ -165,7 +190,8 @@ func Rank(cidStr string) int {
 	}
 	// Opaque locators. Codec-only: their multihash is identity (0x00), so
 	// there is nothing to match on the mh side.
-	if codec == CodeNzbRelease || codec == CodeURL || codec == CodeCard {
+	if codec == CodeNzbRelease || codec == CodeURL || codec == CodeCard ||
+		codec == CodeYtVideo || codec == CodeExtPlay || codec == CodeProviderFile {
 		return RankLocator
 	}
 	// nzb-posting: codec-only, checked BEFORE the mh switch below — its

internal/config/config.go

@@ -40,6 +40,14 @@ type Config struct {
 
 	// Mount configuration
 	MountsDir string // Path to mounts configuration (default: /meta-core/mounts)
+
+	// UDP service discovery (meta-discovery v1). Replaces the file-based
+	// registry that used to live under /meta-core/services; see
+	// docs/project-architecture/service-discovery.md.
+	EnableUDPDiscovery  bool   // Announce + listen on the multicast group (default: true)
+	DiscoveryGroup      string // IPv4 multicast group (default: 239.255.77.1)
+	DiscoveryPort       int    // UDP port (default: 9399)
+	DiscoveryIntervalMS int    // Unsolicited announce interval in ms (default: 10000)
 }
 
 // Load creates a Config from environment variables
@@ -63,6 +71,10 @@ func Load() *Config {
 		WatchIntervalMS:        getEnvInt("WATCH_INTERVAL_MS", 1000),
 		DebounceMS:             getEnvInt("DEBOUNCE_MS", 30000),
 		EnableFileWatcher:      getEnvBool("ENABLE_FILE_WATCHER", true),
+		EnableUDPDiscovery:     getEnvBool("ENABLE_UDP_DISCOVERY", true),
+		DiscoveryGroup:         getEnv("DISCOVERY_GROUP", "239.255.77.1"),
+		DiscoveryPort:          getEnvInt("DISCOVERY_PORT", 9399),
+		DiscoveryIntervalMS:    getEnvInt("DISCOVERY_INTERVAL_MS", 10000),
 	}
 
 	// Set mounts directory
@@ -71,26 +83,18 @@ func Load() *Config {
 	return cfg
 }
 
-// LockFilePath returns the path to the leader lock file
+// LockFilePath returns the path to the Redis-volume mutex. Held by
+// docker/leader-election.sh; nothing reads it, and it is NOT service
+// discovery — see docs/project-architecture/service-discovery.md.
 func (c *Config) LockFilePath() string {
 	return c.MetaCorePath + "/locks/kv-leader.lock"
 }
 
-// InfoFilePath returns the path to the leader info file
-func (c *Config) InfoFilePath() string {
-	return c.MetaCorePath + "/locks/kv-leader.info"
-}
-
 // RedisDataDir returns the path to Redis data directory
 func (c *Config) RedisDataDir() string {
 	return c.MetaCorePath + "/db/redis"
 }
 
-// ServicesDir returns the path to services directory
-func (c *Config) ServicesDir() string {
-	return c.MetaCorePath + "/services"
-}
-
 // MountsFilePath returns the path to the mounts configuration file
 func (c *Config) MountsFilePath() string {
 	return c.MountsDir + "/mounts.json"

internal/discovery/cleaner.go

@@ -1,196 +0,0 @@
-package discovery
-
-import (
-	"encoding/json"
-	"log"
-	"os"
-	"path/filepath"
-	"sync"
-	"time"
-
-	"github.com/metazla/meta-core/internal/config"
-)
-
-// CleanupStats holds statistics about the cleanup process
-type CleanupStats struct {
-	LastRunTime     string `json:"lastRunTime,omitempty"`
-	ServicesRemoved int    `json:"servicesRemoved"`
-	TotalRuns       int    `json:"totalRuns"`
-	Errors          int    `json:"errors"`
-}
-
-// Cleaner handles periodic cleanup of dead service registration files
-type Cleaner struct {
-	config      *config.Config
-	servicesDir string
-	ownFile     string // Our own service file (never delete)
-
-	stats    CleanupStats
-	stopChan chan struct{}
-	wg       sync.WaitGroup
-	mu       sync.RWMutex
-}
-
-// NewCleaner creates a new service cleaner
-func NewCleaner(cfg *config.Config) *Cleaner {
-	hostname, _ := os.Hostname()
-	return &Cleaner{
-		config:      cfg,
-		servicesDir: cfg.ServicesDir(),
-		ownFile:     filepath.Join(cfg.ServicesDir(), cfg.ServiceName+"-"+hostname+".json"),
-		stopChan:    make(chan struct{}),
-	}
-}
-
-// Start begins the cleanup loop
-func (c *Cleaner) Start() error {
-	log.Printf("[Cleaner] Starting dead service cleanup (interval: %dms, threshold: %dms)",
-		c.config.CleanupIntervalMS, c.config.DeadServiceThresholdMS)
-
-	c.wg.Add(1)
-	go c.cleanupLoop()
-
-	return nil
-}
-
-// Stop stops the cleanup loop
-func (c *Cleaner) Stop() error {
-	log.Println("[Cleaner] Stopping dead service cleanup...")
-	close(c.stopChan)
-	c.wg.Wait()
-	return nil
-}
-
-// cleanupLoop runs the periodic cleanup
-func (c *Cleaner) cleanupLoop() {
-	defer c.wg.Done()
-
-	// Run an initial cleanup shortly after starting
-	initialDelay := time.NewTimer(30 * time.Second)
-	select {
-	case <-c.stopChan:
-		initialDelay.Stop()
-		return
-	case <-initialDelay.C:
-		c.runCleanup()
-	}
-
-	ticker := time.NewTicker(time.Duration(c.config.CleanupIntervalMS) * time.Millisecond)
-	defer ticker.Stop()
-
-	for {
-		select {
-		case <-c.stopChan:
-			return
-		case <-ticker.C:
-			c.runCleanup()
-		}
-	}
-}
-
-// runCleanup scans the services directory and removes dead services
-func (c *Cleaner) runCleanup() {
-	c.mu.Lock()
-	c.stats.TotalRuns++
-	c.stats.LastRunTime = time.Now().UTC().Format(time.RFC3339)
-	c.mu.Unlock()
-
-	entries, err := os.ReadDir(c.servicesDir)
-	if err != nil {
-		if !os.IsNotExist(err) {
-			log.Printf("[Cleaner] Failed to read services directory: %v", err)
-			c.mu.Lock()
-			c.stats.Errors++
-			c.mu.Unlock()
-		}
-		return
-	}
-
-	threshold := time.Duration(c.config.DeadServiceThresholdMS) * time.Millisecond
-	removedCount := 0
-
-	for _, entry := range entries {
-		if entry.IsDir() || filepath.Ext(entry.Name()) != ".json" {
-			continue
-		}
-
-		filePath := filepath.Join(c.servicesDir, entry.Name())
-
-		// Never delete our own service file
-		if filePath == c.ownFile {
-			continue
-		}
-
-		// Check if service is dead
-		isDead, serviceName, age := c.isServiceDead(filePath, threshold)
-		if isDead {
-			if err := os.Remove(filePath); err != nil {
-				log.Printf("[Cleaner] Failed to remove dead service file %s: %v", entry.Name(), err)
-				c.mu.Lock()
-				c.stats.Errors++
-				c.mu.Unlock()
-			} else {
-				ageMinutes := age.Minutes()
-				log.Printf("[Cleaner] Removed dead service: %s (last heartbeat: %.1f minutes ago)", serviceName, ageMinutes)
-				removedCount++
-			}
-		}
-	}
-
-	if removedCount > 0 {
-		c.mu.Lock()
-		c.stats.ServicesRemoved += removedCount
-		c.mu.Unlock()
-		log.Printf("[Cleaner] Cleanup complete: removed %d dead service(s)", removedCount)
-	}
-}
-
-// isServiceDead checks if a service file represents a dead service
-// Returns: isDead, serviceName, age since last heartbeat
-func (c *Cleaner) isServiceDead(filePath string, threshold time.Duration) (bool, string, time.Duration) {
-	data, err := os.ReadFile(filePath)
-	if err != nil {
-		// Can't read file - treat as dead to clean up corrupted files
-		log.Printf("[Cleaner] Cannot read service file %s: %v (treating as dead)", filepath.Base(filePath), err)
-		return true, filepath.Base(filePath), threshold
-	}
-
-	var info ServiceInfo
-	if err := json.Unmarshal(data, &info); err != nil {
-		// Corrupted JSON - skip rather than delete (might be recoverable)
-		log.Printf("[Cleaner] Skipping corrupted service file %s: %v", filepath.Base(filePath), err)
-		return false, "", 0
-	}
-
-	// Parse last heartbeat timestamp
-	if info.LastHeartbeat == "" {
-		// No heartbeat timestamp - treat as dead
-		return true, info.Name, threshold
-	}
-
-	lastHeartbeat, err := time.Parse(time.RFC3339, info.LastHeartbeat)
-	if err != nil {
-		// Invalid timestamp - treat as dead
-		log.Printf("[Cleaner] Invalid timestamp in service file %s: %v (treating as dead)", filepath.Base(filePath), err)
-		return true, info.Name, threshold
-	}
-
-	age := time.Since(lastHeartbeat)
-	if age > threshold {
-		return true, info.Name, age
-	}
-
-	return false, info.Name, age
-}
-
-// Stats returns a copy of the current cleanup statistics
-func (c *Cleaner) Stats() CleanupStats {
-	c.mu.RLock()
-	defer c.mu.RUnlock()
-	return CleanupStats{
-		LastRunTime:     c.stats.LastRunTime,
-		ServicesRemoved: c.stats.ServicesRemoved,
-		TotalRuns:       c.stats.TotalRuns,
-		Errors:          c.stats.Errors,
-	}
-}

internal/discovery/service.go

@@ -1,286 +0,0 @@
-package discovery
-
-import (
-	"encoding/json"
-	"fmt"
-	"log"
-	"net"
-	"os"
-	"path/filepath"
-	"sync"
-	"time"
-
-	"github.com/metazla/meta-core/internal/config"
-)
-
-// ServiceInfo contains simplified service registration data
-// URLs are obtained via the /urls API endpoint
-type ServiceInfo struct {
-	Name          string `json:"name"`
-	Hostname      string `json:"hostname"`
-	BaseUrl       string `json:"baseUrl"`
-	Status        string `json:"status"`
-	LastHeartbeat string `json:"lastHeartbeat"`
-}
-
-// Service handles service registration and discovery
-type Service struct {
-	config      *config.Config
-	servicesDir string
-	serviceFile string
-	info        *ServiceInfo
-	mu          sync.RWMutex
-
-	stopChan chan struct{}
-	wg       sync.WaitGroup
-}
-
-// NewService creates a new service discovery instance
-func NewService(cfg *config.Config) *Service {
-	hostname, _ := os.Hostname()
-	return &Service{
-		config:      cfg,
-		servicesDir: cfg.ServicesDir(),
-		serviceFile: filepath.Join(cfg.ServicesDir(), cfg.ServiceName+"-"+hostname+".json"),
-		stopChan:    make(chan struct{}),
-	}
-}
-
-// Start begins service registration and heartbeat
-func (s *Service) Start() error {
-	log.Printf("[Discovery] Starting service discovery for %s", s.config.ServiceName)
-
-	// Ensure services directory exists
-	if err := os.MkdirAll(s.servicesDir, 0755); err != nil {
-		return fmt.Errorf("failed to create services directory: %w", err)
-	}
-
-	// Build and register service info
-	s.info = s.buildServiceInfo()
-	if err := s.register(); err != nil {
-		return fmt.Errorf("failed to register service: %w", err)
-	}
-
-	// Start heartbeat loop
-	s.wg.Add(1)
-	go s.heartbeatLoop()
-
-	return nil
-}
-
-// Stop stops service discovery and unregisters
-func (s *Service) Stop() error {
-	log.Println("[Discovery] Stopping service discovery...")
-	close(s.stopChan)
-	s.wg.Wait()
-
-	// Unregister by removing service file
-	if err := os.Remove(s.serviceFile); err != nil && !os.IsNotExist(err) {
-		log.Printf("[Discovery] Failed to remove service file: %v", err)
-	}
-
-	return nil
-}
-
-// buildServiceInfo creates the service info for this instance
-func (s *Service) buildServiceInfo() *ServiceInfo {
-	hostname, _ := os.Hostname()
-	ip := getLocalIP()
-
-	// Browser-facing nav URL: prefer META_CORE_PUBLIC_URL (the reachable URL
-	// when there's no Caddy perimeter in front — e.g. a debug-direct port),
-	// then BASE_URL (the Caddy perimeter URL), then the internal IP.
-	var baseUrl string
-	if s.config.PublicURL != "" {
-		baseUrl = s.config.PublicURL
-	} else if s.config.BaseURL != "" {
-		baseUrl = s.config.BaseURL
-	} else {
-		baseUrl = fmt.Sprintf("http://%s:%d", ip, s.config.APIPort)
-	}
-
-	info := &ServiceInfo{
-		Name:          s.config.ServiceName,
-		Hostname:      hostname,
-		BaseUrl:       baseUrl,
-		Status:        "running",
-		LastHeartbeat: time.Now().UTC().Format(time.RFC3339),
-	}
-
-	return info
-}
-
-// register writes service info to file
-func (s *Service) register() error {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	return s.writeServiceInfo(s.info)
-}
-
-// writeServiceInfo atomically writes service info to file
-func (s *Service) writeServiceInfo(info *ServiceInfo) error {
-	tempPath := s.serviceFile + ".tmp"
-
-	data, err := json.MarshalIndent(info, "", "  ")
-	if err != nil {
-		return err
-	}
-
-	if err := os.WriteFile(tempPath, data, 0644); err != nil {
-		return err
-	}
-
-	return os.Rename(tempPath, s.serviceFile)
-}
-
-// heartbeatLoop periodically updates the last heartbeat
-func (s *Service) heartbeatLoop() {
-	defer s.wg.Done()
-
-	ticker := time.NewTicker(time.Duration(s.config.HeartbeatIntervalMS) * time.Millisecond)
-	defer ticker.Stop()
-
-	for {
-		select {
-		case <-s.stopChan:
-			return
-		case <-ticker.C:
-			s.heartbeat()
-		}
-	}
-}
-
-// heartbeat updates the last heartbeat timestamp
-func (s *Service) heartbeat() {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	if s.info == nil {
-		return
-	}
-
-	s.info.LastHeartbeat = time.Now().UTC().Format(time.RFC3339)
-
-	if err := s.writeServiceInfo(s.info); err != nil {
-		log.Printf("[Discovery] Failed to update heartbeat: %v", err)
-	}
-}
-
-// UpdateStatus updates the service status
-func (s *Service) UpdateStatus(status string) error {
-	s.mu.Lock()
-	defer s.mu.Unlock()
-
-	if s.info == nil {
-		return fmt.Errorf("service not registered")
-	}
-
-	s.info.Status = status
-	s.info.LastHeartbeat = time.Now().UTC().Format(time.RFC3339)
-	return s.writeServiceInfo(s.info)
-}
-
-// Discover finds a service by name
-// Looks for files matching pattern: name-*.json (hostname-based naming)
-func (s *Service) Discover(name string) (*ServiceInfo, error) {
-	// First try exact match for backward compatibility
-	exactPath := filepath.Join(s.servicesDir, name+".json")
-	if data, err := os.ReadFile(exactPath); err == nil {
-		var info ServiceInfo
-		if err := json.Unmarshal(data, &info); err == nil {
-			return s.checkStale(&info), nil
-		}
-	}
-
-	// Search for hostname-based files: name-*.json
-	pattern := filepath.Join(s.servicesDir, name+"-*.json")
-	matches, err := filepath.Glob(pattern)
-	if err != nil {
-		return nil, err
-	}
-
-	// Return the first valid service found
-	for _, match := range matches {
-		data, err := os.ReadFile(match)
-		if err != nil {
-			continue
-		}
-
-		var info ServiceInfo
-		if err := json.Unmarshal(data, &info); err != nil {
-			continue
-		}
-
-		return s.checkStale(&info), nil
-	}
-
-	return nil, nil
-}
-
-// checkStale marks a service as stale if heartbeat is too old
-func (s *Service) checkStale(info *ServiceInfo) *ServiceInfo {
-	lastHeartbeat, err := time.Parse(time.RFC3339, info.LastHeartbeat)
-	if err == nil {
-		staleThreshold := time.Duration(s.config.StaleThresholdMS) * time.Millisecond
-		if time.Since(lastHeartbeat) > staleThreshold {
-			info.Status = "stale"
-		}
-	}
-	return info
-}
-
-// DiscoverAll finds all registered services
-func (s *Service) DiscoverAll() ([]*ServiceInfo, error) {
-	entries, err := os.ReadDir(s.servicesDir)
-	if err != nil {
-		if os.IsNotExist(err) {
-			return []*ServiceInfo{}, nil
-		}
-		return nil, err
-	}
-
-	var services []*ServiceInfo
-	for _, entry := range entries {
-		if entry.IsDir() || filepath.Ext(entry.Name()) != ".json" {
-			continue
-		}
-
-		filePath := filepath.Join(s.servicesDir, entry.Name())
-		data, err := os.ReadFile(filePath)
-		if err != nil {
-			log.Printf("[Discovery] Failed to read service file %s: %v", entry.Name(), err)
-			continue
-		}
-
-		var info ServiceInfo
-		if err := json.Unmarshal(data, &info); err != nil {
-			log.Printf("[Discovery] Failed to parse service file %s: %v", entry.Name(), err)
-			continue
-		}
-
-		services = append(services, s.checkStale(&info))
-	}
-
-	return services, nil
-}
-
-// getLocalIP returns the local IP address
-func getLocalIP() string {
-	addrs, err := net.InterfaceAddrs()
-	if err != nil {
-		hostname, _ := os.Hostname()
-		return hostname
-	}
-
-	for _, addr := range addrs {
-		if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
-			if ipnet.IP.To4() != nil {
-				return ipnet.IP.String()
-			}
-		}
-	}
-
-	hostname, _ := os.Hostname()
-	return hostname
-}

internal/identity/challenge.go

@@ -0,0 +1,126 @@
+package identity
+
+// In-memory, single-use challenge store backing proof-of-possession on the
+// account operations that need it (reveal, delete).
+//
+// In memory on purpose: a challenge is worthless once redeemed and worthless
+// once expired, so persisting it would only widen the window in which a leaked
+// one is useful. A meta-core restart invalidates every challenge in flight,
+// which costs a client one retry.
+//
+// Mirrors the sign-in challenge in meta-watch's src/auth.rs, down to the TTL —
+// the browser signs immediately, so seconds is the right order and a narrow
+// window bounds replay if one ever surfaces in a proxy log.
+
+import (
+	"errors"
+	"sync"
+	"time"
+)
+
+// ChallengeTTL is how long an issued challenge stays answerable.
+const ChallengeTTL = 120 * time.Second
+
+// maxChallenges caps the store. An unauthenticated caller can mint challenges
+// for any uid it can name, so the map is attacker-growable; without a ceiling
+// that is a memory-exhaustion lever. At the cap, issuing fails rather than
+// evicting: dropping someone else's live challenge on demand would let an
+// attacker deny sign-outs, which is worse than making them retry.
+const maxChallenges = 4096
+
+var (
+	// ErrChallengeUnknown covers absent, already-redeemed and expired alike.
+	// One error for all three deliberately: distinguishing them tells a prober
+	// whether a challenge string was ever real.
+	ErrChallengeUnknown = errors.New("challenge is unknown, already used, or expired")
+	ErrChallengeFull    = errors.New("too many challenges in flight; try again shortly")
+)
+
+type challengeEntry struct {
+	uid     string
+	action  Action
+	expires time.Time
+}
+
+// ChallengeStore issues and redeems challenges. Safe for concurrent use.
+type ChallengeStore struct {
+	mu      sync.Mutex
+	entries map[string]challengeEntry
+	ttl     time.Duration
+	// now is swappable so the tests can age entries without sleeping.
+	now func() time.Time
+}
+
+func NewChallengeStore() *ChallengeStore {
+	return &ChallengeStore{
+		entries: make(map[string]challengeEntry),
+		ttl:     ChallengeTTL,
+		now:     time.Now,
+	}
+}
+
+// Issue mints a challenge for (uid, action) and remembers it until redeemed or
+// expired. Returns the literal text the client signs and its expiry.
+func (s *ChallengeStore) Issue(uid string, action Action) (string, time.Time, error) {
+	if !validUID(uid) {
+		return "", time.Time{}, errors.New("invalid uid")
+	}
+	if !ValidAction(action) {
+		return "", time.Time{}, errors.New("unknown action")
+	}
+	text, err := NewChallengeText(uid, action)
+	if err != nil {
+		return "", time.Time{}, err
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.sweepLocked()
+	if len(s.entries) >= maxChallenges {
+		return "", time.Time{}, ErrChallengeFull
+	}
+	expires := s.now().Add(s.ttl)
+	s.entries[text] = challengeEntry{uid: uid, action: action, expires: expires}
+	return text, expires, nil
+}
+
+// Redeem consumes a challenge, asserting it was issued for this exact uid and
+// action. Single-use: the entry is dropped on any lookup that finds it, so a
+// mismatched redemption burns the challenge rather than leaving it to be
+// retried against a different account.
+func (s *ChallengeStore) Redeem(text, uid string, action Action) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	entry, ok := s.entries[text]
+	if !ok {
+		return ErrChallengeUnknown
+	}
+	delete(s.entries, text)
+	if s.now().After(entry.expires) {
+		return ErrChallengeUnknown
+	}
+	if entry.uid != uid || entry.action != action {
+		return ErrChallengeUnknown
+	}
+	// Re-read the signed bytes rather than trusting the map key alone: the
+	// signature covers `text`, so `text` is what has to name this uid+action.
+	if !ChallengeMatches(text, uid, action) {
+		return ErrChallengeUnknown
+	}
+	return nil
+}
+
+// sweepLocked drops expired entries. Caller holds the lock.
+//
+// Called only from Issue: with no background goroutine, expiry is enforced
+// lazily on the one path that grows the map, which is exactly where the bound
+// matters.
+func (s *ChallengeStore) sweepLocked() {
+	now := s.now()
+	for text, e := range s.entries {
+		if now.After(e.expires) {
+			delete(s.entries, text)
+		}
+	}
+}

internal/identity/noble_interop_test.go

@@ -0,0 +1,43 @@
+package identity
+
+import (
+	"encoding/base64"
+	"testing"
+)
+
+// A real signature produced by @noble/secp256k1 v3 — the library the dashboard
+// and meta-watch both sign with — pinned as a fixture and verified here.
+//
+// This is the one seam neither side's own tests can cover: Go signs DER, the
+// browser signs 64-byte compact, and every unit test above verifies signatures
+// this package produced itself. If the encodings ever disagree, the gate fails
+// closed in production (nobody can delete their own account) while every other
+// test stays green. Regenerate with:
+//
+//	node -e 'import("@noble/secp256k1").then(async s => { … })'
+//
+// against the same fixed scalar (32 zero bytes with 42 in the last).
+func TestVerify_AcceptsARealNobleV3Signature(t *testing.T) {
+	const (
+		uid       = "ztbJ71eLvfmGXw2ydaSPHavfwjva5Bzadutw2tvYDVFVY"
+		challenge = "metamesh-identity-v1:delete:ztbJ71eLvfmGXw2ydaSPHavfwjva5Bzadutw2tvYDVFVY:deadbeef"
+		sigB64    = "lIiZGL0j9l/w2WXwzwe56cICnusuYdD3oaTuYfFTtNJBR9MolXFPk3014WQeAlvmbX4LfnW+TQz4asqoSwmSAQ=="
+	)
+
+	sig, err := base64.StdEncoding.DecodeString(sigB64)
+	if err != nil {
+		t.Fatalf("decode fixture: %v", err)
+	}
+	if len(sig) != 64 {
+		t.Fatalf("fixture is %d bytes, expected noble's 64-byte compact form", len(sig))
+	}
+	if err := Verify(uid, []byte(challenge), sig); err != nil {
+		t.Fatalf("a genuine browser signature must verify: %v", err)
+	}
+
+	// And the same signature must not verify over a different challenge — a
+	// verifier that ignored the payload would pass the line above too.
+	if err := Verify(uid, []byte(challenge+"x"), sig); err == nil {
+		t.Fatal("the fixture verified over the wrong payload")
+	}
+}

internal/identity/verify.go

@@ -0,0 +1,160 @@
+package identity
+
+// Signature verification against a uid, and the challenge vocabulary that
+// makes a signature mean "I hold this account's private key" rather than
+// "meta-core signed something for me".
+//
+// The asymmetry that motivates this file: meta-core *holds* every private key,
+// so it can sign as anybody. A signature is therefore only proof of possession
+// if the payload is one meta-core refuses to sign on request — hence
+// ChallengeDomain, which POST /api/identity/sign rejects outright. Without that
+// refusal an attacker mints their own authorisation in one extra call and the
+// whole gate is decoration.
+//
+// Verification itself needs no stored state: a uid *is* the public key
+// ("z" + base58btc(33-byte compressed sec1)), so the pubkey is recovered from
+// the uid the caller names. Mirrors `verify_local` / `verify_local_compact` in
+// meta-watch's src/record/sign.rs — same curve, same digest, both signature
+// encodings.
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/subtle"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4/ecdsa"
+	"github.com/mr-tron/base58"
+)
+
+// ChallengeDomain prefixes every byte string that authorises an account
+// operation. POST /api/identity/sign and /sign-batch refuse payloads carrying
+// it, so the only way to produce one is to hold the key yourself.
+//
+// Versioned because it is a wire commitment: changing it invalidates every
+// challenge in flight, which is harmless, but changing it *silently* would let
+// an old-domain payload keep working. Bump it deliberately.
+const ChallengeDomain = "metamesh-identity-v1:"
+
+// Action is the operation a challenge authorises. A challenge minted to reveal
+// a key must not also delete the account, so the action is inside the signed
+// bytes and is re-checked at redemption.
+type Action string
+
+const (
+	ActionReveal Action = "reveal"
+	ActionDelete Action = "delete"
+)
+
+// ValidAction reports whether a is an action a challenge may be issued for.
+func ValidAction(a Action) bool {
+	return a == ActionReveal || a == ActionDelete
+}
+
+// ValidUID exposes the uid shape check to callers outside this package (the
+// API layer, which must reject a hostile uid before it reaches a Redis SCAN
+// pattern or a file path).
+func ValidUID(uid string) bool { return validUID(uid) }
+
+// IsChallengePayload reports whether b is (or claims to be) an account
+// authorisation payload. Used by the signing endpoints to refuse minting one.
+//
+// Deliberately a prefix test on raw bytes rather than a parse: anything that
+// merely *looks* like a challenge is refused, so a malformed or future-version
+// payload fails closed instead of being signed.
+func IsChallengePayload(b []byte) bool {
+	return strings.HasPrefix(string(b), ChallengeDomain)
+}
+
+// PubkeyFromUID recovers the compressed public key a uid encodes.
+func PubkeyFromUID(uid string) (*secp256k1.PublicKey, error) {
+	if !validUID(uid) {
+		return nil, fmt.Errorf("invalid uid: %q", uid)
+	}
+	if !strings.HasPrefix(uid, "z") {
+		return nil, errors.New("uid is not multibase base58btc (missing 'z' prefix)")
+	}
+	raw, err := base58.Decode(uid[1:])
+	if err != nil {
+		return nil, fmt.Errorf("uid is not valid base58: %w", err)
+	}
+	if len(raw) != 33 {
+		return nil, fmt.Errorf("uid decodes to %d bytes, want a 33-byte compressed pubkey", len(raw))
+	}
+	pub, err := secp256k1.ParsePubKey(raw)
+	if err != nil {
+		return nil, fmt.Errorf("uid is not a point on secp256k1: %w", err)
+	}
+	return pub, nil
+}
+
+// Verify checks sig over SHA-256(payload) against the public key inside uid.
+//
+// Accepts both encodings in circulation: DER (what Sign emits, and what User
+// Data Layer records carry) and 64-byte compact r‖s (what the browser emits —
+// noble-secp256k1 v3 dropped DER, and meta-watch's sign-in already sends
+// compact). Rejecting either would break one of the two callers.
+func Verify(uid string, payload, sig []byte) error {
+	pub, err := PubkeyFromUID(uid)
+	if err != nil {
+		return err
+	}
+	parsed, err := parseSignature(sig)
+	if err != nil {
+		return err
+	}
+	digest := sha256.Sum256(payload)
+	if !parsed.Verify(digest[:], pub) {
+		return errors.New("signature does not verify for this uid")
+	}
+	return nil
+}
+
+func parseSignature(sig []byte) (*ecdsa.Signature, error) {
+	if len(sig) == 64 {
+		var r, s secp256k1.ModNScalar
+		// SetByteSlice reports overflow (>= curve order), which is not a valid
+		// scalar. A zero r or s is likewise never produced by a real signer.
+		if r.SetByteSlice(sig[:32]) || r.IsZero() {
+			return nil, errors.New("compact signature has an invalid r")
+		}
+		if s.SetByteSlice(sig[32:]) || s.IsZero() {
+			return nil, errors.New("compact signature has an invalid s")
+		}
+		return ecdsa.NewSignature(&r, &s), nil
+	}
+	parsed, err := ecdsa.ParseDERSignature(sig)
+	if err != nil {
+		return nil, fmt.Errorf("signature is neither 64-byte compact nor valid DER: %w", err)
+	}
+	return parsed, nil
+}
+
+// NewChallengeText mints the literal string a client signs. The uid and action
+// are inside it, so a signature cannot be lifted from one account or operation
+// onto another even if the nonce leaks.
+func NewChallengeText(uid string, action Action) (string, error) {
+	nonce := make([]byte, 32)
+	if _, err := rand.Read(nonce); err != nil {
+		return "", fmt.Errorf("read nonce: %w", err)
+	}
+	return ChallengeDomain + string(action) + ":" + uid + ":" + hex.EncodeToString(nonce), nil
+}
+
+// ChallengeMatches reports whether text is a well-formed challenge for exactly
+// this uid and action. The store already keys on the full text, so this is a
+// belt-and-braces re-read of the signed bytes themselves: it is the signed
+// content, not the lookup key, that a verifier must agree with.
+//
+// Compared in constant time — the text is a bearer secret until redeemed.
+func ChallengeMatches(text, uid string, action Action) bool {
+	want := ChallengeDomain + string(action) + ":" + uid + ":"
+	if len(text) <= len(want) {
+		return false
+	}
+	return subtle.ConstantTimeCompare([]byte(text[:len(want)]), []byte(want)) == 1
+}

internal/identity/verify_test.go

@@ -0,0 +1,278 @@
+package identity
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/decred/dcrd/dcrec/secp256k1/v4"
+	"github.com/decred/dcrd/dcrec/secp256k1/v4/ecdsa"
+)
+
+// The whole gate rests on a uid being the public key: verification consults no
+// stored state, so a signature is checked against the account the caller names
+// rather than against whatever key meta-core happens to hold.
+func TestVerify_AcceptsDERFromOurOwnSigner(t *testing.T) {
+	id, err := Generate()
+	if err != nil {
+		t.Fatalf("generate: %v", err)
+	}
+	payload := []byte(ChallengeDomain + "delete:" + id.UID + ":abcdef")
+
+	sig, err := Sign(id, payload)
+	if err != nil {
+		t.Fatalf("sign: %v", err)
+	}
+	if err := Verify(id.UID, payload, sig); err != nil {
+		t.Fatalf("DER signature from Sign must verify: %v", err)
+	}
+}
+
+// The browser is the signer that matters here, and noble-secp256k1 v3 emits
+// 64-byte compact r‖s — it dropped DER entirely. A verifier that took only DER
+// would reject every real proof while passing this package's own tests.
+func TestVerify_AcceptsCompactAsTheBrowserEmitsIt(t *testing.T) {
+	id, err := Generate()
+	if err != nil {
+		t.Fatalf("generate: %v", err)
+	}
+	payload := []byte("some challenge text")
+
+	raw, _ := hex.DecodeString(id.PrivateKeyHex)
+	priv := secp256k1.PrivKeyFromBytes(raw)
+	digest := sha256.Sum256(payload)
+	der := ecdsa.Sign(priv, digest[:])
+
+	// Re-encode the same signature compactly, the way the browser would.
+	parsed, err := ecdsa.ParseDERSignature(der.Serialize())
+	if err != nil {
+		t.Fatalf("parse own DER: %v", err)
+	}
+	r := parsed.R()
+	sc := parsed.S()
+	compact := make([]byte, 0, 64)
+	rb := r.Bytes()
+	sb := sc.Bytes()
+	compact = append(compact, rb[:]...)
+	compact = append(compact, sb[:]...)
+
+	if err := Verify(id.UID, payload, compact); err != nil {
+		t.Fatalf("compact signature must verify: %v", err)
+	}
+}
+
+func TestVerify_RejectsAnotherAccountsSignature(t *testing.T) {
+	alice, _ := Generate()
+	mallory, _ := Generate()
+	payload := []byte("challenge for alice")
+
+	sig, err := Sign(mallory, payload)
+	if err != nil {
+		t.Fatalf("sign: %v", err)
+	}
+	if err := Verify(alice.UID, payload, sig); err == nil {
+		t.Fatal("a signature by mallory must not verify as alice")
+	}
+}
+
+func TestVerify_RejectsTamperedPayload(t *testing.T) {
+	id, _ := Generate()
+	sig, _ := Sign(id, []byte("delete account A"))
+	if err := Verify(id.UID, []byte("delete account B"), sig); err == nil {
+		t.Fatal("a signature must not verify over different bytes")
+	}
+}
+
+func TestVerify_RejectsGarbageSignatureEncodings(t *testing.T) {
+	id, _ := Generate()
+	for name, sig := range map[string][]byte{
+		"empty":            {},
+		"short":            {1, 2, 3},
+		"zero compact":     make([]byte, 64),
+		"not der":          []byte("this is not a signature at all......."),
+		"63 bytes":         make([]byte, 63),
+		"65 bytes non-der": make([]byte, 65),
+	} {
+		if err := Verify(id.UID, []byte("x"), sig); err == nil {
+			t.Errorf("%s: expected rejection", name)
+		}
+	}
+}
+
+func TestPubkeyFromUID_RejectsMalformedUIDs(t *testing.T) {
+	id, _ := Generate()
+	for name, uid := range map[string]string{
+		"empty":          "",
+		"no z prefix":    id.UID[1:],
+		"truncated":      id.UID[:20],
+		"path traversal": "../../etc/passwd",
+		"with slash":     "z/" + id.UID,
+		"not on curve":   "z" + strings.Repeat("1", 45),
+	} {
+		if _, err := PubkeyFromUID(uid); err == nil {
+			t.Errorf("%s (%q): expected rejection", name, uid)
+		}
+	}
+	if _, err := PubkeyFromUID(id.UID); err != nil {
+		t.Fatalf("a real uid must parse: %v", err)
+	}
+}
+
+// The refusal that makes proof-of-possession mean anything on a node holding
+// every private key. If this ever returns false for a challenge, an attacker
+// asks /api/identity/sign to authorise their own delete.
+func TestIsChallengePayload_CatchesAnythingInTheDomain(t *testing.T) {
+	yes := [][]byte{
+		[]byte(ChallengeDomain),
+		[]byte(ChallengeDomain + "delete:zAlice:beef"),
+		[]byte(ChallengeDomain + "some-future-action:whatever"),
+		[]byte("metamesh-identity-v1:"), // literal, in case the const drifts
+	}
+	for _, b := range yes {
+		if !IsChallengePayload(b) {
+			t.Errorf("must refuse to sign %q", b)
+		}
+	}
+	no := [][]byte{
+		{},
+		[]byte("metamesh-identity-v2:delete:zAlice"), // different domain, not ours to refuse
+		[]byte("a record payload"),
+		[]byte(" " + ChallengeDomain), // not a prefix
+	}
+	for _, b := range no {
+		if IsChallengePayload(b) {
+			t.Errorf("must still sign %q", b)
+		}
+	}
+}
+
+func TestChallengeMatches_TiesTheTextToUIDAndAction(t *testing.T) {
+	text, err := NewChallengeText("zAlice", ActionDelete)
+	if err != nil {
+		t.Fatalf("mint: %v", err)
+	}
+	if !ChallengeMatches(text, "zAlice", ActionDelete) {
+		t.Fatal("its own uid+action must match")
+	}
+	if ChallengeMatches(text, "zBob", ActionDelete) {
+		t.Fatal("another uid must not match")
+	}
+	if ChallengeMatches(text, "zAlice", ActionReveal) {
+		t.Fatal("another action must not match")
+	}
+	// A prefix-only uid must not slip through: "zAlic" is a prefix of "zAlice",
+	// and a naive HasPrefix on the uid alone would accept it.
+	if ChallengeMatches(text, "zAlic", ActionDelete) {
+		t.Fatal("a uid that is a prefix of the real one must not match")
+	}
+}
+
+func TestNewChallengeText_IsUnpredictable(t *testing.T) {
+	seen := make(map[string]struct{}, 64)
+	for i := 0; i < 64; i++ {
+		text, err := NewChallengeText("zAlice", ActionDelete)
+		if err != nil {
+			t.Fatalf("mint: %v", err)
+		}
+		if _, dup := seen[text]; dup {
+			t.Fatal("challenge repeated — the nonce is not random")
+		}
+		seen[text] = struct{}{}
+	}
+}
+
+// --- challenge store --------------------------------------------------------
+
+func TestChallengeStore_RedeemIsSingleUse(t *testing.T) {
+	s := NewChallengeStore()
+	text, _, err := s.Issue("zAlice", ActionDelete)
+	if err != nil {
+		t.Fatalf("issue: %v", err)
+	}
+	if err := s.Redeem(text, "zAlice", ActionDelete); err != nil {
+		t.Fatalf("first redeem: %v", err)
+	}
+	if err := s.Redeem(text, "zAlice", ActionDelete); err == nil {
+		t.Fatal("a challenge must not be redeemable twice — that is replay")
+	}
+}
+
+// A challenge minted to *look at* a key must not delete the account, and one
+// minted for Alice must not act on Bob. Both are inside the signed text, so a
+// store that ignored them would authorise the wrong operation with a perfectly
+// valid signature.
+func TestChallengeStore_RedeemRefusesWrongUIDOrAction(t *testing.T) {
+	s := NewChallengeStore()
+
+	text, _, _ := s.Issue("zAlice", ActionReveal)
+	if err := s.Redeem(text, "zAlice", ActionDelete); err == nil {
+		t.Fatal("a reveal challenge must not authorise a delete")
+	}
+
+	text2, _, _ := s.Issue("zAlice", ActionDelete)
+	if err := s.Redeem(text2, "zBob", ActionDelete); err == nil {
+		t.Fatal("alice's challenge must not authorise deleting bob")
+	}
+}
+
+// A failed redemption still consumes the challenge, so a wrong guess costs a
+// round trip rather than leaving the nonce up for another attempt.
+func TestChallengeStore_FailedRedeemStillBurnsIt(t *testing.T) {
+	s := NewChallengeStore()
+	text, _, _ := s.Issue("zAlice", ActionDelete)
+	_ = s.Redeem(text, "zBob", ActionDelete)
+	if err := s.Redeem(text, "zAlice", ActionDelete); err == nil {
+		t.Fatal("a burnt challenge must stay burnt for its rightful owner too")
+	}
+}
+
+func TestChallengeStore_Expires(t *testing.T) {
+	s := NewChallengeStore()
+	now := time.Unix(1_700_000_000, 0)
+	s.now = func() time.Time { return now }
+
+	text, expires, _ := s.Issue("zAlice", ActionDelete)
+	if !expires.Equal(now.Add(ChallengeTTL)) {
+		t.Fatalf("expiry %v, want %v", expires, now.Add(ChallengeTTL))
+	}
+	now = now.Add(ChallengeTTL + time.Second)
+	if err := s.Redeem(text, "zAlice", ActionDelete); err == nil {
+		t.Fatal("an expired challenge must not redeem")
+	}
+}
+
+// Issuing is unauthenticated, so the map is attacker-growable. The cap is what
+// stops that being a memory-exhaustion lever; expiry sweeping is what stops the
+// cap being reached by honest traffic.
+func TestChallengeStore_CapsInFlightAndSweepsExpired(t *testing.T) {
+	s := NewChallengeStore()
+	now := time.Unix(1_700_000_000, 0)
+	s.now = func() time.Time { return now }
+
+	for i := 0; i < maxChallenges; i++ {
+		if _, _, err := s.Issue("zAlice", ActionDelete); err != nil {
+			t.Fatalf("issue %d: %v", i, err)
+		}
+	}
+	if _, _, err := s.Issue("zAlice", ActionDelete); err == nil {
+		t.Fatal("expected the store to refuse once full")
+	}
+
+	// Once they age out, the next issue sweeps and succeeds again.
+	now = now.Add(ChallengeTTL + time.Second)
+	if _, _, err := s.Issue("zAlice", ActionDelete); err != nil {
+		t.Fatalf("after expiry the store must accept again: %v", err)
+	}
+}
+
+func TestChallengeStore_RefusesInvalidInputs(t *testing.T) {
+	s := NewChallengeStore()
+	if _, _, err := s.Issue("../etc", ActionDelete); err == nil {
+		t.Fatal("a uid that is not uid-shaped must be refused")
+	}
+	if _, _, err := s.Issue("zAlice", Action("sudo")); err == nil {
+		t.Fatal("an unknown action must be refused")
+	}
+}

internal/meshdisco/node.go

@@ -0,0 +1,434 @@
+package meshdisco
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"sort"
+	"sync"
+	"syscall"
+	"time"
+
+	"golang.org/x/net/ipv4"
+)
+
+// Config configures a Node. Payload is a function rather than a value so the
+// announce is rebuilt from live state on every tick — that is what keeps the
+// announced URLs and GET /urls from drifting apart.
+type Config struct {
+	Name     string
+	Instance string
+	Role     string
+	Version  string
+
+	Group    string
+	Port     int
+	Interval time.Duration
+
+	// Payload returns the identity/URL fields for this announce. Name,
+	// Instance, Role, Version and the envelope are filled in by the Node.
+	Payload func() (baseURL string, status string, urls *URLs)
+}
+
+func (c *Config) applyDefaults() {
+	if c.Group == "" {
+		c.Group = DefaultGroup
+	}
+	if c.Port == 0 {
+		c.Port = DefaultPort
+	}
+	if c.Interval <= 0 {
+		c.Interval = DefaultInterval
+	}
+	if c.Role == "" {
+		c.Role = RoleService
+	}
+}
+
+// Node is one participant in the mesh: it announces itself, answers probes,
+// and keeps a TTL map of everyone else it has heard from.
+type Node struct {
+	cfg   Config
+	group net.IP
+
+	pc     *ipv4.PacketConn
+	closer interface{ Close() error }
+
+	// ifaces are the multicast-capable interfaces we joined and send on.
+	// A container attached to two docker networks (metashare-app on `pcs`
+	// and `metamesh-mesh`, metawatch-* on `metawatch` and `metamesh-mesh`)
+	// has two entries here, and MUST be announced on both — sending via the
+	// default route alone silently covers only one network.
+	ifaces []net.Interface
+
+	// sendMu serialises SetMulticastInterface + WriteTo, which are a
+	// two-step operation on one shared socket.
+	sendMu sync.Mutex
+
+	mu        sync.RWMutex
+	neighbors map[string]*Neighbor
+
+	stopChan chan struct{}
+	stopOnce sync.Once
+	wg       sync.WaitGroup
+}
+
+// New creates a Node. It does not touch the network until Start.
+func New(cfg Config) *Node {
+	cfg.applyDefaults()
+	return &Node{
+		cfg:       cfg,
+		neighbors: make(map[string]*Neighbor),
+		stopChan:  make(chan struct{}),
+	}
+}
+
+// Start opens the multicast socket, joins the group on every eligible
+// interface, and begins announcing. A join failure on one interface is logged
+// and skipped rather than fatal — matching the ENABLE_MDNS precedent in the
+// Rust services, where a host that blocks multicast degrades instead of
+// failing to boot.
+func (n *Node) Start() error {
+	n.group = net.ParseIP(n.cfg.Group)
+	if n.group == nil || n.group.To4() == nil {
+		return fmt.Errorf("meshdisco: invalid multicast group %q", n.cfg.Group)
+	}
+
+	lc := net.ListenConfig{Control: reusePort}
+	conn, err := lc.ListenPacket(context.Background(), "udp4", fmt.Sprintf(":%d", n.cfg.Port))
+	if err != nil {
+		return fmt.Errorf("meshdisco: listen on :%d: %w", n.cfg.Port, err)
+	}
+	n.closer = conn
+
+	pc := ipv4.NewPacketConn(conn)
+	// TTL 1: link-local only. Discovery never routes off the local segment;
+	// the two-host topology keeps two separate meshes by design.
+	if err := pc.SetMulticastTTL(1); err != nil {
+		log.Printf("[meshdisco] Warning: could not set multicast TTL: %v", err)
+	}
+	n.pc = pc
+
+	n.ifaces = eligibleInterfaces()
+	if len(n.ifaces) == 0 {
+		log.Println("[meshdisco] Warning: no multicast-capable interfaces found; discovery will be inert")
+	}
+
+	group := &net.UDPAddr{IP: n.group}
+	joined := 0
+	for i := range n.ifaces {
+		if err := pc.JoinGroup(&n.ifaces[i], group); err != nil {
+			log.Printf("[meshdisco] Warning: join %s on %s failed: %v", n.cfg.Group, n.ifaces[i].Name, err)
+			continue
+		}
+		joined++
+	}
+	log.Printf("[meshdisco] Listening on %s:%d as %s/%s (joined %d of %d interfaces)",
+		n.cfg.Group, n.cfg.Port, n.cfg.Name, n.cfg.Instance, joined, len(n.ifaces))
+
+	n.wg.Add(2)
+	go n.readLoop()
+	go n.announceLoop()
+
+	return nil
+}
+
+// Stop closes the socket and waits for the loops to exit. It sends a final
+// announce with status "stopping" so neighbours drop us immediately instead of
+// waiting out the staleness window.
+func (n *Node) Stop() error {
+	var err error
+	n.stopOnce.Do(func() {
+		n.sendAnnounce(nil, "stopping")
+		close(n.stopChan)
+		if n.closer != nil {
+			err = n.closer.Close()
+		}
+		n.wg.Wait()
+	})
+	return err
+}
+
+// Probe multicasts a discovery message on every interface. Every listener
+// replies immediately, so a caller does not have to wait out an announce
+// interval. This is what makes the protocol usable on the boot path.
+func (n *Node) Probe() {
+	n.broadcast(Message{V: ProtocolVersion, Type: TypeDiscovery})
+}
+
+// Neighbors returns everyone heard from within the staleness window, sorted by
+// name. Entries older than that are dropped as a side effect — expiry is a
+// read-time concern, so there is no reaper goroutine and no equivalent of the
+// old cleaner.go.
+func (n *Node) Neighbors() []Neighbor {
+	cutoff := time.Now().Add(-n.cfg.Interval * LivenessFactor)
+
+	n.mu.Lock()
+	out := make([]Neighbor, 0, len(n.neighbors))
+	for k, nb := range n.neighbors {
+		if nb.LastSeen.Before(cutoff) {
+			delete(n.neighbors, k)
+			continue
+		}
+		out = append(out, *nb)
+	}
+	n.mu.Unlock()
+
+	sort.Slice(out, func(i, j int) bool {
+		if out[i].Name != out[j].Name {
+			return out[i].Name < out[j].Name
+		}
+		return out[i].Instance < out[j].Instance
+	})
+	return out
+}
+
+// NeighborsByName collapses multiple instances of one service down to the most
+// recently seen, which is the shape the nav menu wants (and what the existing
+// /api/services dedup contract asserts).
+func (n *Node) NeighborsByName() []Neighbor {
+	best := make(map[string]Neighbor)
+	for _, nb := range n.Neighbors() {
+		if cur, ok := best[nb.Name]; !ok || nb.LastSeen.After(cur.LastSeen) {
+			best[nb.Name] = nb
+		}
+	}
+	out := make([]Neighbor, 0, len(best))
+	for _, nb := range best {
+		out = append(out, nb)
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Name < out[j].Name })
+	return out
+}
+
+// Self returns this node's own announce, so callers can render themselves in
+// the menu without waiting to hear their own multicast echo back.
+func (n *Node) Self() Neighbor {
+	return Neighbor{Message: n.buildAnnounce("running"), LastSeen: time.Now()}
+}
+
+func (n *Node) readLoop() {
+	defer n.wg.Done()
+	buf := make([]byte, ReadBufferSize)
+
+	for {
+		select {
+		case <-n.stopChan:
+			return
+		default:
+		}
+
+		nRead, _, src, err := n.pc.ReadFrom(buf)
+		if err != nil {
+			select {
+			case <-n.stopChan:
+				return
+			default:
+			}
+			log.Printf("[meshdisco] Read error: %v", err)
+			continue
+		}
+
+		var msg Message
+		if err := json.Unmarshal(buf[:nRead], &msg); err != nil {
+			// Malformed or foreign traffic on the group — ignore quietly.
+			continue
+		}
+		if msg.V != ProtocolVersion {
+			continue
+		}
+		// Drop our own multicast echo. Loopback is left enabled so that a
+		// single-container test still sees traffic; we filter by identity
+		// instead of relying on the socket option.
+		if msg.Instance != "" && msg.Instance == n.cfg.Instance && msg.Name == n.cfg.Name {
+			continue
+		}
+
+		switch msg.Type {
+		case TypeDiscovery:
+			// Unicast the reply straight back to the prober's source
+			// address. The kernel picks the right interface by route, and
+			// the prober's ephemeral source port is where it is listening.
+			n.sendAnnounce(src, "running")
+		case TypeAnnounce:
+			n.record(msg, src)
+		}
+	}
+}
+
+func (n *Node) record(msg Message, src net.Addr) {
+	addr := ""
+	if src != nil {
+		if udp, ok := src.(*net.UDPAddr); ok {
+			addr = udp.IP.String()
+		} else {
+			addr = src.String()
+		}
+	}
+
+	if msg.Status == "stopping" {
+		n.mu.Lock()
+		delete(n.neighbors, msg.key())
+		n.mu.Unlock()
+		return
+	}
+
+	nb := &Neighbor{Message: msg, Addr: addr, LastSeen: time.Now()}
+	n.mu.Lock()
+	n.neighbors[msg.key()] = nb
+	n.mu.Unlock()
+}
+
+func (n *Node) announceLoop() {
+	defer n.wg.Done()
+
+	// Announce immediately, then probe once so the map fills without waiting
+	// a full interval for everyone else's ticker.
+	n.sendAnnounce(nil, "running")
+	n.Probe()
+
+	ticker := time.NewTicker(n.cfg.Interval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-n.stopChan:
+			return
+		case <-ticker.C:
+			n.sendAnnounce(nil, "running")
+		}
+	}
+}
+
+func (n *Node) buildAnnounce(status string) Message {
+	msg := Message{
+		V:        ProtocolVersion,
+		Type:     TypeAnnounce,
+		Name:     n.cfg.Name,
+		Instance: n.cfg.Instance,
+		Role:     n.cfg.Role,
+		Version:  n.cfg.Version,
+		Status:   status,
+	}
+	if n.cfg.Payload != nil {
+		baseURL, st, urls := n.cfg.Payload()
+		msg.BaseUrl = baseURL
+		if st != "" && status == "running" {
+			msg.Status = st
+		}
+		// Only meta-core carries a URLs block; a service announcing one
+		// would let any container on the network impersonate the core.
+		if n.cfg.Role == RoleCore {
+			msg.URLs = urls
+		}
+	}
+	return msg
+}
+
+// sendAnnounce multicasts when dst is nil, or unicasts to dst (a probe reply).
+func (n *Node) sendAnnounce(dst net.Addr, status string) {
+	msg := n.buildAnnounce(status)
+	if dst == nil {
+		n.broadcast(msg)
+		return
+	}
+	body, err := json.Marshal(msg)
+	if err != nil {
+		return
+	}
+	n.sendMu.Lock()
+	defer n.sendMu.Unlock()
+	if _, err := n.pc.WriteTo(body, nil, dst); err != nil {
+		log.Printf("[meshdisco] Reply to %s failed: %v", dst, err)
+	}
+}
+
+// broadcast writes one message to the group once per eligible interface.
+// Writing once and letting the routing table choose would reach exactly one
+// network, which is the failure mode this protocol exists to avoid.
+func (n *Node) broadcast(msg Message) {
+	if n.pc == nil {
+		return
+	}
+	body, err := json.Marshal(msg)
+	if err != nil {
+		return
+	}
+	dst := &net.UDPAddr{IP: n.group, Port: n.cfg.Port}
+
+	n.sendMu.Lock()
+	defer n.sendMu.Unlock()
+	for i := range n.ifaces {
+		if err := n.pc.SetMulticastInterface(&n.ifaces[i]); err != nil {
+			log.Printf("[meshdisco] Warning: select interface %s failed: %v", n.ifaces[i].Name, err)
+			continue
+		}
+		if _, err := n.pc.WriteTo(body, nil, dst); err != nil {
+			log.Printf("[meshdisco] Warning: send on %s failed: %v", n.ifaces[i].Name, err)
+		}
+	}
+}
+
+// eligibleInterfaces returns every up, non-loopback, multicast-capable
+// interface that has an IPv4 address.
+func eligibleInterfaces() []net.Interface {
+	all, err := net.Interfaces()
+	if err != nil {
+		log.Printf("[meshdisco] Warning: could not enumerate interfaces: %v", err)
+		return nil
+	}
+
+	var out []net.Interface
+	for _, ifi := range all {
+		if ifi.Flags&net.FlagUp == 0 ||
+			ifi.Flags&net.FlagLoopback != 0 ||
+			ifi.Flags&net.FlagMulticast == 0 {
+			continue
+		}
+		addrs, err := ifi.Addrs()
+		if err != nil {
+			continue
+		}
+		for _, a := range addrs {
+			if ipnet, ok := a.(*net.IPNet); ok && ipnet.IP.To4() != nil {
+				out = append(out, ifi)
+				break
+			}
+		}
+	}
+	return out
+}
+
+// reusePort sets SO_REUSEADDR so a second listener (a test, or a sidecar) can
+// bind the same multicast port on the same host.
+func reusePort(_, _ string, c syscall.RawConn) error {
+	var serr error
+	err := c.Control(func(fd uintptr) {
+		serr = syscall.SetsockoptInt(int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1)
+	})
+	if err != nil {
+		return err
+	}
+	return serr
+}
+
+// LocalIPv4 returns this host's first non-loopback IPv4 address, or the
+// hostname when none can be determined. Same fallback the file-based registry
+// used (discovery/service.go), kept identical so announced URLs don't shift.
+func LocalIPv4() string {
+	addrs, err := net.InterfaceAddrs()
+	if err == nil {
+		for _, addr := range addrs {
+			if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
+				if ipnet.IP.To4() != nil {
+					return ipnet.IP.String()
+				}
+			}
+		}
+	}
+	host, _ := os.Hostname()
+	return host
+}

internal/meshdisco/proto.go

@@ -0,0 +1,132 @@
+// Package meshdisco implements meta-discovery v1: UDP multicast service
+// discovery for the meta-* services.
+//
+// It replaces two file-based mechanisms that both required a shared
+// /meta-core volume:
+//
+//   - /meta-core/locks/kv-leader.info — a one-line file holding meta-core's
+//     API URL, read at boot to locate meta-core.
+//   - /meta-core/services/<name>-<host>.json — per-service registration files
+//     aggregated into the dashboard's service nav.
+//
+// Both answer the same question — where is meta-core, and who else is on this
+// network — so one announce packet answers both. Discovery scope becomes the
+// docker network the container is attached to rather than the volume it
+// mounts, which is what lets per-app CasaOS stacks and the meta-watch island
+// see their neighbours without sharing storage.
+//
+// The wire protocol is documented in
+// docs/project-architecture/service-discovery.md. Keep this file and that doc
+// in step — every other language implementation is written against the doc.
+package meshdisco
+
+import "time"
+
+const (
+	// ProtocolVersion is the `v` field on every message. Receivers ignore
+	// messages carrying a version they don't know.
+	ProtocolVersion = 1
+
+	// DefaultGroup is the IPv4 multicast group. Deliberately NOT beacon's
+	// 239.255.99.1 (sandbox/beacon), so the two protocols cannot cross-talk
+	// if they ever share a network.
+	DefaultGroup = "239.255.77.1"
+
+	// DefaultPort is the UDP port. Deliberately NOT beacon's 9099, for the
+	// same reason.
+	DefaultPort = 9399
+
+	// DefaultInterval is how often an unsolicited announce is emitted.
+	DefaultInterval = 10 * time.Second
+
+	// LivenessFactor multiplies the announce interval to get the staleness
+	// window: a neighbour last seen longer ago than interval*factor is
+	// dropped. This replaces the old heartbeat file + cleaner.go reaper.
+	LivenessFactor = 3
+
+	// ReadBufferSize is the datagram receive buffer. Beacon's reference
+	// implementation uses 1 KiB, which truncates a realistic payload; an
+	// announce carrying the full URLs block is comfortably under 8 KiB.
+	ReadBufferSize = 8192
+
+	// TypeDiscovery is a probe: "who is out there?". Sent at startup and on
+	// a manual refresh, answered immediately by every listener.
+	TypeDiscovery = "discovery"
+
+	// TypeAnnounce is a service describing itself, sent unsolicited on a
+	// ticker and unicast in reply to a probe.
+	TypeAnnounce = "announce"
+
+	// RoleCore marks meta-core itself — the only role that carries a URLs
+	// block. Consumers locating meta-core filter on this.
+	RoleCore = "core"
+
+	// RoleService marks every other meta-* service.
+	RoleService = "service"
+)
+
+// URLs mirrors meta-core's existing GET /urls response (api.URLsResponse)
+// minus redisUrl, which the api-mediated-access lockdown retired. Embedding it
+// in the announce makes the announce a drop-in for the /urls hop that
+// LeaderClient performs today; /urls itself stays, since meta-search and
+// meta-share still call it.
+type URLs struct {
+	Hostname          string `json:"hostname"`
+	BaseUrl           string `json:"baseUrl"`
+	ApiUrl            string `json:"apiUrl"`
+	WebdavUrl         string `json:"webdavUrl"`
+	WebdavUrlInternal string `json:"webdavUrlInternal"`
+}
+
+// Message is the single wire type: both probe and announce are one JSON
+// datagram. Everything but `v` and `type` is omitted on a probe.
+type Message struct {
+	V    int    `json:"v"`
+	Type string `json:"type"`
+
+	// Name is the service name, e.g. "meta-core", "meta-sort".
+	Name string `json:"name,omitempty"`
+	// Instance distinguishes two instances of the same Name — the container
+	// hostname. Also used to recognise and drop our own multicast echo.
+	Instance string `json:"instance,omitempty"`
+	// Role is RoleCore or RoleService.
+	Role string `json:"role,omitempty"`
+	// Version is the service's build version, for display only.
+	Version string `json:"version,omitempty"`
+	// Status is "running" | "starting" | "stopping".
+	Status string `json:"status,omitempty"`
+
+	// BaseUrl is the browser-facing URL the nav menu links to. Built with
+	// the same three-way fallback the file registry used:
+	// META_CORE_PUBLIC_URL -> BASE_URL -> http://<local-ip>:<port>.
+	BaseUrl string `json:"baseUrl,omitempty"`
+
+	// URLs is populated only when Role == RoleCore.
+	URLs *URLs `json:"urls,omitempty"`
+
+	// Token is reserved for a future HMAC over the payload. v1 senders omit
+	// it and v1 receivers ignore it; see the doc's Security section.
+	Token string `json:"token,omitempty"`
+}
+
+// Neighbor is a Message plus the receive-side facts the sender cannot state
+// about itself.
+type Neighbor struct {
+	Message
+	// Addr is the source address the datagram arrived from. Taken from the
+	// packet, never from the payload — a sender does not get to claim its
+	// own IP.
+	Addr string `json:"addr"`
+	// LastSeen is when we last received an announce from this instance.
+	LastSeen time.Time `json:"lastSeen"`
+}
+
+// key identifies a neighbour entry. Two instances of the same service are
+// distinct neighbours; callers that want one row per service (the nav menu)
+// collapse by Name themselves.
+func (m Message) key() string {
+	if m.Instance == "" {
+		return m.Name
+	}
+	return m.Name + "|" + m.Instance
+}

internal/storage/cid_resolution.go

@@ -309,6 +309,10 @@ func (c *Client) DeleteRoot(uuid string) error {
 	if err := c.client.SRem(ctx, c.buildIndexKey(), uuid).Err(); err != nil {
 		return fmt.Errorf("srem index: %w", err)
 	}
+	// Marked so the incremental search-index refresh reads it, finds it gone,
+	// and evicts it — otherwise a deleted root keeps answering searches until
+	// the next full rebuild.
+	c.markDirtyLocked(ctx, uuid)
 	return nil
 }
 
@@ -418,3 +422,50 @@ func (c *Client) GetMetadataDocument(uuid string) (*MetadataDocument, error) {
 		Duplicates: dups,
 	}, nil
 }
+
+// RegisterFileTuple records one physical file under its midhash256 CID, the
+// same way the file watcher does for every file it scans: mint a UUID root
+// (filePath/sizeByte/mtimeNano) and write `cids/<midhash>`, whose hook
+// registers the cid:<midhash> reverse alias. Content already known under
+// another path is recorded as a duplicate; the same path just refreshes
+// size/mtime.
+//
+// Returns the root and whether it was newly minted. Shared by the watcher and
+// POST /api/files/register, which is how a box running with the watcher off
+// (a meta-watch client core) still gets files it writes under /files/plugin
+// resolvable by CID.
+func (c *Client) RegisterFileTuple(absPath string, size, mtimeNano int64, midhash string) (string, bool, error) {
+	if midhash == "" {
+		return "", false, fmt.Errorf("midhash is required")
+	}
+	uuid, err := c.GetByCID(midhash)
+	if err != nil {
+		return "", false, fmt.Errorf("GetByCID(%s): %w", midhash, err)
+	}
+
+	if uuid == "" {
+		uuid, err = c.Mint(absPath, size, mtimeNano)
+		if err != nil {
+			return "", false, fmt.Errorf("Mint(%s): %w", absPath, err)
+		}
+		if err := c.SetProperty(uuid, CIDsKeyPrefix+midhash, "true"); err != nil {
+			return uuid, true, fmt.Errorf("SetProperty cids/%s for %s: %w", midhash, uuid, err)
+		}
+		return uuid, true, nil
+	}
+
+	existing, _ := c.GetProperty(uuid, "filePath")
+	if existing != absPath {
+		if _, err := c.AddDuplicatePath(uuid, absPath); err != nil {
+			return uuid, false, fmt.Errorf("AddDuplicatePath %s @ %s: %w", uuid, absPath, err)
+		}
+		return uuid, false, nil
+	}
+	if _, err := c.MergeMetadataFlat(uuid, map[string]string{
+		"sizeByte":  strconv.FormatInt(size, 10),
+		"mtimeNano": strconv.FormatInt(mtimeNano, 10),
+	}); err != nil {
+		return uuid, false, fmt.Errorf("refresh tuple for %s: %w", uuid, err)
+	}
+	return uuid, false, nil
+}

internal/storage/client.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"os"
 	"sort"
 	"strconv"
 	"strings"
@@ -173,6 +174,7 @@ func (c *Client) SetMetadataFlat(hashID string, metadata map[string]string) erro
 	if err := c.client.SAdd(ctx, c.buildIndexKey(), hashID).Err(); err != nil {
 		return fmt.Errorf("sadd index failed: %w", err)
 	}
+	c.markDirtyLocked(ctx, hashID)
 
 	// Auto-register reverse-index aliases for any cids/<cid> key-set members in
 	// the payload. That is the ONLY shape recognised — the legacy flat cid_* /
@@ -257,6 +259,7 @@ func (c *Client) SetProperty(hashID, property, value string) error {
 	if err := c.client.SAdd(ctx, c.buildIndexKey(), hashID).Err(); err != nil {
 		return fmt.Errorf("sadd index failed: %w", err)
 	}
+	c.markDirtyLocked(ctx, hashID)
 
 	// Auto-register reverse-index alias if this is a CID field.
 	_ = c.maybeAddAliasFromFieldLocked(ctx, hashID, property, value)
@@ -325,6 +328,10 @@ func (c *Client) DeleteMetadata(hashID string) (int64, error) {
 	if err := c.client.SRem(ctx, c.buildIndexKey(), hashID).Err(); err != nil {
 		return deletedCount, fmt.Errorf("srem index failed: %w", err)
 	}
+	// Marked, not unmarked: the incremental refresh reads the record, finds it
+	// gone, and evicts it from the search index. Skipping this would leave a
+	// deleted record answering searches until the next full rebuild.
+	c.markDirtyLocked(ctx, hashID)
 
 	return deletedCount, nil
 }
@@ -441,6 +448,7 @@ func (c *Client) MergeMetadataFlat(hashID string, metadata map[string]string) (i
 	if err := c.client.SAdd(ctx, c.buildIndexKey(), hashID).Err(); err != nil {
 		return len(metadata), fmt.Errorf("sadd index failed: %w", err)
 	}
+	c.markDirtyLocked(ctx, hashID)
 
 	// Auto-register reverse-index aliases for any cids/<cid> key-set members in
 	// the payload. That is the ONLY shape recognised — the legacy flat cid_* /
@@ -468,6 +476,7 @@ func (c *Client) DeleteProperty(hashID, property string) error {
 		return err
 	}
 	c.removeFieldLocked(ctx, hashID, property)
+	c.markDirtyLocked(ctx, hashID)
 	return nil
 }
 
@@ -521,6 +530,7 @@ func (c *Client) AddToSet(hashID, property, value string) (bool, error) {
 	if err := c.client.SAdd(ctx, c.buildIndexKey(), hashID).Err(); err != nil {
 		return true, fmt.Errorf("sadd index failed: %w", err)
 	}
+	c.markDirtyLocked(ctx, hashID)
 
 	return true, nil
 }
@@ -574,11 +584,16 @@ func (c *Client) RemoveFromSet(hashID, property, value string) (bool, error) {
 		}
 		// The key is gone, so the field name must leave the index too.
 		c.removeFieldLocked(ctx, hashID, property)
+		c.markDirtyLocked(ctx, hashID)
 		return true, nil
 	}
 
 	newValue := strings.Join(newValues, "|")
-	return true, c.client.Set(ctx, key, newValue, 0).Err()
+	err = c.client.Set(ctx, key, newValue, 0).Err()
+	// The field survives with fewer members, so no field-index change — but the
+	// VALUE changed, which is exactly what the search index caches.
+	c.markDirtyLocked(ctx, hashID)
+	return true, err
 }
 
 // FileTuple holds the (uuid, path, size, mtime, midhash) record for one
@@ -691,6 +706,44 @@ type SearchTuple struct {
 // haystack — must stay in sync with the fields the search handler documents.
 var searchIndexFields = []string{"title", "fileName", "originaltitle", "showtitle", "filePath"}
 
+// defaultIndexExcludePrefixes are field-name prefixes kept OUT of the in-memory
+// search index. Redis still stores them and every per-record read still returns
+// them — this narrows the *index*, never the store.
+//
+// `categories/newznab/<code>` is the raw Newznab numeric category code, which
+// METADATA_KEYS documents as a mirror of the canonical `categories/<label>`
+// vocabulary that rides alongside it. Nothing in meta-gateway, meta-search,
+// meta-watch or meta-core reads it, and it is the single largest contributor to
+// the index: measured on a live 19.6k-record corpus, `categories/*` was 40% of
+// the whole keyspace and the `newznab` sub-vocabulary was 59% of that — ~24% of
+// all keys, for zero readers.
+//
+// ⚠ Excluding the WHOLE `categories/` family instead would be a security bug,
+// not an optimisation. `categories/XXX` (and `categories/XXX/<leaf>`) is the
+// server-side adult-content enforcement point — meta-search's
+// `query_eval::fields_are_adult` and meta-gateway's `cards::fields_are_adult`
+// both match on it, and the `exclude_adult` preference defaults to ON. A record
+// served from the index without its categories would read as non-adult and the
+// filter would fail OPEN. Only prefixes with no semantic readers belong here.
+var defaultIndexExcludePrefixes = []string{"categories/newznab/"}
+
+// indexExcludePrefixes resolves the exclusion list, allowing an operator to
+// override it with a comma-separated META_CORE_INDEX_EXCLUDE_PREFIXES. An
+// explicitly empty value disables exclusion entirely (index everything).
+func indexExcludePrefixes() []string {
+	raw, set := os.LookupEnv("META_CORE_INDEX_EXCLUDE_PREFIXES")
+	if !set {
+		return defaultIndexExcludePrefixes
+	}
+	out := make([]string, 0, 4)
+	for _, p := range strings.Split(raw, ",") {
+		if p = strings.TrimSpace(p); p != "" {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
 // GetSearchIndexTuples reads EVERY record's full metadata in a single keyspace
 // SCAN pass over the flat `file:{hashID}/{field}` keys plus batched MGETs,
 // grouped by record — one bulk pass instead of a SCAN+MGET per record (which is
@@ -712,6 +765,7 @@ func (c *Client) GetSearchIndexTuples() ([]SearchTuple, error) {
 	indexKey := c.buildIndexKey()     // {filePrefix}__index__ (a SET, skip it)
 	pattern := filePrefix + "*"
 
+	excluded := indexExcludePrefixes()
 	records := make(map[string]map[string]string)
 	keyBatch := make([]string, 0, 1000)
 
@@ -762,6 +816,11 @@ func (c *Client) GetSearchIndexTuples() ([]SearchTuple, error) {
 			if strings.HasSuffix(k, "/"+FieldsField) {
 				continue
 			}
+			// Index-excluded fields are skipped here rather than after the
+			// MGET, so an excluded key costs neither the fetch nor the memory.
+			if _, field, ok := c.splitRecordKey(k); ok && hasAnyPrefix(field, excluded) {
+				continue
+			}
 			keyBatch = append(keyBatch, k)
 			if len(keyBatch) >= 1000 {
 				if err := flush(); err != nil {
@@ -780,18 +839,23 @@ func (c *Client) GetSearchIndexTuples() ([]SearchTuple, error) {
 
 	out := make([]SearchTuple, 0, len(records))
 	for hashID, fields := range records {
-		var sb strings.Builder
+		// Shared with the incremental path (search_dirty.go) so the two can
-		for _, f := range searchIndexFields {
+		// never disagree about what is searchable.
-			if v, ok := fields[f]; ok && v != "" {
+		out = append(out, SearchTuple{HashID: hashID, Haystack: buildHaystack(fields), Fields: fields})
-				sb.WriteString(strings.ToLower(v))
-				sb.WriteByte('\n')
-			}
-		}
-		out = append(out, SearchTuple{HashID: hashID, Haystack: sb.String(), Fields: fields})
 	}
 	return out, nil
 }
 
+// hasAnyPrefix reports whether s starts with any of the given prefixes.
+func hasAnyPrefix(s string, prefixes []string) bool {
+	for _, p := range prefixes {
+		if strings.HasPrefix(s, p) {
+			return true
+		}
+	}
+	return false
+}
+
 // GetMemoryInfo returns Redis memory usage information
 func (c *Client) GetMemoryInfo() (string, error) {
 	c.mu.RLock()

internal/storage/domain_screen_migration.go

@@ -0,0 +1,193 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// The one-shot corpus sweep for METADATA_KEYS.md §14.17: the `film` + `tv`
+// domains merged into `screen`, and the standalone-vs-serial split they were
+// really carrying moved to the new `workForm` key.
+//
+// # Why a sweep and not a read-side alias
+//
+// `domain` is **stored, not derived on read** — that is what lets the
+// `contentKind` vocabulary stay open (a peer that has never heard of a kind
+// still routes the record correctly). The price of storing it is that a
+// vocabulary change has to be paid once, in the data: every consumer's filter
+// is an exact match, so a record left saying `film` is invisible to a
+// `domain:screen` wall, and teaching every consumer to accept both spellings
+// forever is exactly the alternation the merge exists to delete.
+//
+// So the values are rewritten at rest, here, and no alias vocabulary survives
+// in query filters. (meta-search additionally normalises on the way into its
+// index, because a record can still arrive from a peer that has not been swept
+// — that is a courtesy for un-swept peers, not a second source of truth.)
+//
+// # Contract
+//
+// Idempotent: a record already carrying `screen` and a `workForm` is skipped,
+// so the endpoint is safe to call repeatedly and safe to call on a fresh box.
+// Returns the number of records **changed**, not the number examined.
+
+// legacyDomainReplacements maps a retired `domain` value to its replacement.
+var legacyDomainReplacements = map[string]string{
+	"film": "screen",
+	"tv":   "screen",
+}
+
+// workFormByContentKind is the `contentKind` → `workForm` table from
+// METADATA_KEYS.md §1.
+//
+// ⚠ Mirror of the Rust table in `meta-feeder-sdk::domain` (and of
+// meta-search's copy). It exists here only to backfill the pre-merge corpus —
+// meta-core never classifies a record it is given, and nothing else in Go reads
+// it. If the tables ever disagree, the writers win: this one is a one-shot.
+var workFormByContentKind = map[string]string{
+	// screen
+	"movie":   "standalone",
+	"series":  "serial",
+	"episode": "serial",
+	// music — an album is a closed work, not an ongoing run.
+	"track":      "standalone",
+	"album":      "standalone",
+	"artist":     "standalone",
+	"musicVideo": "standalone",
+	"djMix":      "standalone",
+	"liveSet":    "standalone",
+	// literature
+	"book":      "standalone",
+	"audiobook": "standalone",
+	"comic":     "serial",
+	"manga":     "serial",
+	"magazine":  "serial",
+	// science
+	"paper": "standalone",
+	// ⚠ `pack` is deliberately absent: a season pack is `serial`, an album
+	// release `standalone`, and only the writer knows which. A pack that
+	// reaches this sweep without a `workForm` keeps none — inventing one would
+	// be a guess written permanently into the record.
+}
+
+// domainScreenPlan is one record's pending rewrite. Empty strings mean "leave
+// this field alone".
+type domainScreenPlan struct {
+	hashID   string
+	domain   string
+	workForm string
+}
+
+// MigrateDomainScreen rewrites `domain=film|tv` to `domain=screen` and
+// backfills `workForm` from `contentKind` across the whole corpus.
+//
+// Reads in two batched MGET passes (never a per-record SCAN — a single record
+// read costs a full keyspace sweep on this store), then writes only the records
+// that actually change.
+func (c *Client) MigrateDomainScreen(ctx context.Context) (int, error) {
+	plans, err := c.planDomainScreen(ctx)
+	if err != nil {
+		return 0, err
+	}
+	// Writes take the client lock themselves, so they happen after the read
+	// phase has released it.
+	fixed := 0
+	for _, p := range plans {
+		if p.domain != "" {
+			if err := c.SetProperty(p.hashID, "domain", p.domain); err != nil {
+				return fixed, fmt.Errorf("set domain on %s: %w", p.hashID, err)
+			}
+		}
+		if p.workForm != "" {
+			if err := c.SetProperty(p.hashID, "workForm", p.workForm); err != nil {
+				return fixed, fmt.Errorf("set workForm on %s: %w", p.hashID, err)
+			}
+		}
+		fixed++
+	}
+	return fixed, nil
+}
+
+// planDomainScreen is the read half: what would change, without changing it.
+func (c *Client) planDomainScreen(ctx context.Context) ([]domainScreenPlan, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return nil, fmt.Errorf("not connected")
+	}
+
+	hashIDs, err := c.client.SMembers(ctx, c.buildIndexKey()).Result()
+	if err != nil {
+		return nil, fmt.Errorf("smembers index: %w", err)
+	}
+	if len(hashIDs) == 0 {
+		return nil, nil
+	}
+
+	// Three keys per record, in a fixed order so the MGET response decodes by
+	// position: keys[i*3+n] belongs to hashIDs[i].
+	const fieldsPerFile = 3
+	fields := [fieldsPerFile]string{"domain", "workForm", "contentKind"}
+	keys := make([]string, 0, len(hashIDs)*fieldsPerFile)
+	for _, h := range hashIDs {
+		prefix := c.buildKeyPrefix(h)
+		for _, f := range fields {
+			keys = append(keys, prefix+f)
+		}
+	}
+
+	// Chunked so one MGET never carries the whole corpus.
+	const chunk = 3000
+	values := make([]interface{}, 0, len(keys))
+	for start := 0; start < len(keys); start += chunk {
+		end := start + chunk
+		if end > len(keys) {
+			end = len(keys)
+		}
+		got, err := c.client.MGet(ctx, keys[start:end]...).Result()
+		if err != nil {
+			return nil, fmt.Errorf("mget: %w", err)
+		}
+		values = append(values, got...)
+	}
+
+	str := func(i int) string {
+		if i >= len(values) {
+			return ""
+		}
+		s, _ := values[i].(string)
+		return s
+	}
+
+	plans := make([]domainScreenPlan, 0)
+	for i, h := range hashIDs {
+		base := i * fieldsPerFile
+		domain, workForm, contentKind := str(base), str(base+1), str(base+2)
+
+		plan := domainScreenPlan{hashID: h}
+		if replacement, ok := legacyDomainReplacements[domain]; ok {
+			plan.domain = replacement
+		}
+		// A stored `workForm` is authoritative — a `pack` writer knew something
+		// the table cannot. Only an absent one is filled in.
+		if workForm == "" {
+			if form, ok := workFormByContentKind[contentKind]; ok {
+				plan.workForm = form
+			}
+		}
+		if plan.domain != "" || plan.workForm != "" {
+			plans = append(plans, plan)
+		}
+	}
+	return plans, nil
+}
+
+// MigrateDomainScreenWithTimeout is the convenience wrapper used by the API
+// handler. Generous timeout: the read phase is two batched passes, but the
+// write phase is one round-trip per changed field.
+func (c *Client) MigrateDomainScreenWithTimeout() (int, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
+	defer cancel()
+	return c.MigrateDomainScreen(ctx)
+}

internal/storage/domain_screen_migration_test.go

@@ -0,0 +1,140 @@
+package storage
+
+import (
+	"context"
+	"testing"
+)
+
+// seedRecord writes one record's classification fields straight through
+// SetProperty, which is what a real writer uses (it maintains the field index
+// and the root index the sweep reads from).
+func seedRecord(t *testing.T, c *Client, hashID string, fields map[string]string) {
+	t.Helper()
+	for k, v := range fields {
+		if err := c.SetProperty(hashID, k, v); err != nil {
+			t.Fatalf("seed %s/%s: %v", hashID, k, err)
+		}
+	}
+}
+
+// The merge (METADATA_KEYS.md §14.17) is paid in the data: `domain` is stored,
+// not derived on read, so a record left saying `film` is invisible to a
+// `domain:screen` wall. This is the sweep that pays it.
+func TestMigrateDomainScreen_RewritesLegacyDomainsAndBackfillsWorkForm(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedRecord(t, c, "rec-movie", map[string]string{
+		"domain":      "film",
+		"contentKind": "movie",
+	})
+	seedRecord(t, c, "rec-episode", map[string]string{
+		"domain":      "tv",
+		"contentKind": "episode",
+	})
+	// Already current, and already carries both keys: must be left alone.
+	seedRecord(t, c, "rec-current", map[string]string{
+		"domain":      "screen",
+		"contentKind": "series",
+		"workForm":    "serial",
+	})
+	// A different domain entirely — the sweep must not touch it, but it is
+	// still owed the `workForm` backfill.
+	seedRecord(t, c, "rec-book", map[string]string{
+		"domain":      "literature",
+		"contentKind": "book",
+	})
+
+	fixed, err := c.MigrateDomainScreen(context.Background())
+	if err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+	if fixed != 3 {
+		t.Errorf("fixed = %d, want 3 (the two legacy rows + the book's backfill)", fixed)
+	}
+
+	for _, tc := range []struct {
+		hashID   string
+		domain   string
+		workForm string
+	}{
+		{"rec-movie", "screen", "standalone"},
+		{"rec-episode", "screen", "serial"},
+		{"rec-current", "screen", "serial"},
+		{"rec-book", "literature", "standalone"},
+	} {
+		m, err := c.GetMetadataFlat(tc.hashID)
+		if err != nil {
+			t.Fatalf("read %s: %v", tc.hashID, err)
+		}
+		if m["domain"] != tc.domain {
+			t.Errorf("%s domain = %q, want %q", tc.hashID, m["domain"], tc.domain)
+		}
+		if m["workForm"] != tc.workForm {
+			t.Errorf("%s workForm = %q, want %q", tc.hashID, m["workForm"], tc.workForm)
+		}
+	}
+}
+
+// A second pass must find nothing to do — the endpoint is called by hand on
+// each box, and "run it twice" must not mean "write the whole corpus twice".
+func TestMigrateDomainScreen_IsIdempotent(t *testing.T) {
+	c, _ := newTestClient(t, "mm:")
+
+	seedRecord(t, c, "rec-1", map[string]string{
+		"domain":      "tv",
+		"contentKind": "episode",
+	})
+
+	if _, err := c.MigrateDomainScreen(context.Background()); err != nil {
+		t.Fatalf("first pass: %v", err)
+	}
+	fixed, err := c.MigrateDomainScreen(context.Background())
+	if err != nil {
+		t.Fatalf("second pass: %v", err)
+	}
+	if fixed != 0 {
+		t.Errorf("second pass fixed = %d, want 0", fixed)
+	}
+}
+
+// `pack` is the one kind neither routing table can decide — a season pack is
+// `serial`, an album release `standalone`. A pack that reaches the sweep
+// without a `workForm` must keep none: inventing one writes a guess into the
+// record permanently.
+func TestMigrateDomainScreen_NeverGuessesAPacksWorkForm(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedRecord(t, c, "rec-pack", map[string]string{
+		"domain":      "tv",
+		"contentKind": "pack",
+	})
+	// A writer that DID know keeps what it wrote.
+	seedRecord(t, c, "rec-album", map[string]string{
+		"domain":      "music",
+		"contentKind": "pack",
+		"workForm":    "standalone",
+	})
+
+	if _, err := c.MigrateDomainScreen(context.Background()); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+
+	m, err := c.GetMetadataFlat("rec-pack")
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	if m["domain"] != "screen" {
+		t.Errorf("domain = %q, want screen (the domain WAS knowable)", m["domain"])
+	}
+	if _, ok := m["workForm"]; ok {
+		t.Errorf("workForm = %q, want absent", m["workForm"])
+	}
+
+	a, err := c.GetMetadataFlat("rec-album")
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	if a["workForm"] != "standalone" {
+		t.Errorf("workForm = %q, want standalone (writer-supplied, never overwritten)", a["workForm"])
+	}
+}

internal/storage/field_index_test.go

@@ -59,7 +59,7 @@ func TestFieldIndex_SetMetadataFlatIndexesFields(t *testing.T) {
 			"filePath":                      "/files/watch/a.mkv",
 			"sizeByte":                      "123",
 			"cids/bafkreiaaa":               "true",
-			"titles/jpn":                    "ナルト",
+			"titles/jpn/ナルト":                "true",
 			"categories/TV/UHD":             "true",
 			"info/files/0/path":             "a.mkv",
 			"provenance":                    `{"source":"gateway"}`,
@@ -380,7 +380,7 @@ func TestFieldIndex_WarmBuildsEveryMissingIndex(t *testing.T) {
 		// written through the normal path (already indexed).
 		legacy := map[string]map[string]string{
 			"old1": {"filePath": "/a.mkv", "cids/bafkreiaaa": "true"},
-			"old2": {"filePath": "/b.mkv", "titles/jpn": "ナルト", "deep/a/b": "x"},
+			"old2": {"filePath": "/b.mkv", "titles/jpn/ナルト": "true", "deep/a/b": "x"},
 		}
 		for root, fields := range legacy {
 			for f, v := range fields {
@@ -407,7 +407,7 @@ func TestFieldIndex_WarmBuildsEveryMissingIndex(t *testing.T) {
 		if got := fieldNames(t, c, "old1"); !reflect.DeepEqual(got, []string{"cids/bafkreiaaa", "filePath"}) {
 			t.Errorf("old1 index = %v", got)
 		}
-		if got := fieldNames(t, c, "old2"); !reflect.DeepEqual(got, []string{"deep/a/b", "filePath", "titles/jpn"}) {
+		if got := fieldNames(t, c, "old2"); !reflect.DeepEqual(got, []string{"deep/a/b", "filePath", "titles/jpn/ナルト"}) {
 			t.Errorf("old2 index = %v", got)
 		}
 		if got := fieldNames(t, c, "fresh"); !reflect.DeepEqual(got, []string{"title"}) {
@@ -425,7 +425,7 @@ func TestFieldIndex_WarmBuildsEveryMissingIndex(t *testing.T) {
 		if _, err := c.WarmFieldIndexes(); err != nil {
 			t.Fatalf("second WarmFieldIndexes: %v", err)
 		}
-		if got := fieldNames(t, c, "old2"); !reflect.DeepEqual(got, []string{"deep/a/b", "filePath", "titles/jpn"}) {
+		if got := fieldNames(t, c, "old2"); !reflect.DeepEqual(got, []string{"deep/a/b", "filePath", "titles/jpn/ナルト"}) {
 			t.Errorf("old2 index after second warm = %v", got)
 		}
 	})

internal/storage/literature_echo_sweep.go

@@ -0,0 +1,326 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/redis/go-redis/v9"
+
+	"github.com/metazla/meta-core/internal/cid"
+)
+
+// The one-shot corpus sweep for meta-read `docs/reading-model.md` §7:
+// identity and position keys are resolved, never copied from a query, and a
+// card carries no position keys and no `workcid`.
+//
+// # Why a sweep
+//
+// A feeder answering a `workcid:` / `anilistid:` query could stamp the query's
+// own filter values onto what it returned. The gateway persists whatever passes
+// the filter, so the copy became a permanent binding — and stored records never
+// pick up the writer fix: a covered `(upstream, query)` never reaches the
+// feeder again, and the streaming dedup keeps meta-core's copy over a fresh
+// one. So the copies already at rest are removed here, once.
+//
+// What the copies cost: an `anilistid` on a MangaDex site card claims an
+// AniList binding nobody resolved, and meta-read reads a bare `anilistid` as an
+// anchor — the site card then competes with (and can hide) the real AniList
+// card for the same work. A `workcid` or `chapterNumber` on a card makes a work
+// join and sort like a position inside one.
+//
+// # What is swept, and what deliberately is not
+//
+//   - Only `domain=literature` + `fileType=card` records. Nothing else is read
+//     for writing, whatever keys it carries.
+//   - `workcid`, `chapterNumber`, `volumeNumber`, `chapterStart`, `chapterEnd`
+//     go from **every** such card: a card is a work, never a position in one,
+//     so no legitimate writer puts them there.
+//   - `anilistid` goes only from a **site card** — a card whose own `cids/`
+//     key-set holds a site-form card locator and no locator of any other form.
+//     On an anchor card the id *is* the card's identity (its locator is
+//     `("anilist", …)`). A card holding both forms (a cross-source merge) keeps
+//     it: which half the id belongs to is not recoverable at rest, and leaving
+//     a stamp is the safe direction.
+//   - **Chapters are never swept.** A bare `anilistid` on a chapter is graded
+//     Matched by rule, and a query-copied stamp is indistinguishable at rest
+//     from a title-matched one — deleting would drop real bindings with the
+//     fake ones.
+//
+// # Contract
+//
+// Dry-run unless `apply`: the sweep deletes keys, so the default call only
+// reports. Idempotent: a swept record plans nothing on the next pass, so the
+// endpoint is safe to call repeatedly and on a fresh box.
+
+// literatureEchoAnchorSources are the card-locator sources that name an id-bag
+// work (an anchor), never a site.
+//
+// ⚠ Mirror of meta-read `card_cid::is_host_form`. meta-read spells out only
+// `anilist` and `openlibrary`; the others carry no '.', so the '.' test already
+// excludes them and the two rules agree on every locator minted today. They are
+// listed so the rule reads on its own here.
+var literatureEchoAnchorSources = map[string]bool{
+	"anilist":     true,
+	"openlibrary": true,
+	"tmdb":        true,
+	"imdb":        true,
+	"musicbrainz": true,
+	"mal":         true,
+}
+
+// literatureCardEchoFields are removed from every literature card carrying
+// them — position keys and the work reference, none of which a card may hold.
+var literatureCardEchoFields = []string{
+	"workcid",
+	"chapterNumber",
+	"volumeNumber",
+	"chapterStart",
+	"chapterEnd",
+}
+
+// literatureEchoReadFields is the per-record MGET layout: the two gate fields,
+// then `anilistid`, then the echo fields in literatureCardEchoFields order.
+var literatureEchoReadFields = append(
+	[]string{"domain", "fileType", "anilistid"},
+	literatureCardEchoFields...,
+)
+
+// LiteratureEchoSweep is the result of one sweep pass. Planned and Fixed count
+// records; ByKey counts fields per key — removed on an apply pass, that would
+// be removed on a dry run. ByKey is never nil so it serialises as `{}`.
+type LiteratureEchoSweep struct {
+	Planned int
+	Fixed   int
+	ByKey   map[string]int
+}
+
+// literatureEchoPlan is one record's pending deletes, in a fixed order
+// (`anilistid` first, then literatureCardEchoFields order).
+type literatureEchoPlan struct {
+	hashID string
+	fields []string
+}
+
+// isSiteFormCardSource is the site-form rule on an already-decoded source: not
+// an anchor source, and shaped like a host.
+func isSiteFormCardSource(source string) bool {
+	return !literatureEchoAnchorSources[source] && strings.Contains(source, ".")
+}
+
+// isSiteFormCardLocator reports whether a bare CID is a card locator (0x1007)
+// whose source is a site (`mangadex.org`), not an anchor (`anilist`).
+func isSiteFormCardLocator(cidStr string) bool {
+	source, _, err := cid.DecodeCard(cidStr)
+	return err == nil && isSiteFormCardSource(source)
+}
+
+// isSiteCard reports whether a card's field names prove it a site card: at
+// least one site-form `cids/` card locator and no card locator of another form.
+// Non-card members (a content CID) say nothing about which work the card is and
+// are ignored. An empty field list — a record with no field-name index — is
+// never a site card, which keeps its `anilistid`; see planLiteratureEchoes.
+func isSiteCard(fields []string) bool {
+	site := false
+	for _, f := range fields {
+		member := cidFromKeysetField(f)
+		if member == "" {
+			continue
+		}
+		source, _, err := cid.DecodeCard(member)
+		if err != nil {
+			continue
+		}
+		if !isSiteFormCardSource(source) {
+			return false
+		}
+		site = true
+	}
+	return site
+}
+
+// SweepLiteratureEchoes removes query echoes stored on literature cards (see
+// the file comment). With apply=false it only plans.
+//
+// Reads in batched passes (never a per-record SCAN — a single record read
+// costs a full keyspace sweep on this store), then deletes only the planned
+// fields, through DeleteProperty so the field-name index and the search-dirty
+// set stay consistent.
+func (c *Client) SweepLiteratureEchoes(ctx context.Context, apply bool) (LiteratureEchoSweep, error) {
+	res := LiteratureEchoSweep{ByKey: map[string]int{}}
+
+	plans, err := c.planLiteratureEchoes(ctx)
+	if err != nil {
+		return res, err
+	}
+	res.Planned = len(plans)
+
+	if !apply {
+		for _, p := range plans {
+			for _, f := range p.fields {
+				res.ByKey[f]++
+			}
+		}
+		return res, nil
+	}
+
+	// Writes take the client lock themselves, so they happen after the read
+	// phase has released it. ByKey counts what was actually deleted, so a
+	// failure midway reports the true partial state.
+	for _, p := range plans {
+		// DeleteProperty carries its own per-call timeout; checking ctx here is
+		// what makes the wrapper's deadline bound the whole write phase.
+		if err := ctx.Err(); err != nil {
+			return res, err
+		}
+		for _, f := range p.fields {
+			if err := c.DeleteProperty(p.hashID, f); err != nil {
+				return res, fmt.Errorf("delete %s on %s: %w", f, p.hashID, err)
+			}
+			res.ByKey[f]++
+		}
+		res.Fixed++
+	}
+	return res, nil
+}
+
+// planLiteratureEchoes is the read half: what would be deleted, without
+// deleting it.
+func (c *Client) planLiteratureEchoes(ctx context.Context) ([]literatureEchoPlan, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return nil, fmt.Errorf("not connected")
+	}
+
+	hashIDs, err := c.client.SMembers(ctx, c.buildIndexKey()).Result()
+	if err != nil {
+		return nil, fmt.Errorf("smembers index: %w", err)
+	}
+	if len(hashIDs) == 0 {
+		return nil, nil
+	}
+
+	// Pass 1: the gate and echo fields for every record, in a fixed order so
+	// the MGET response decodes by position: keys[i*per+n] belongs to
+	// hashIDs[i].
+	per := len(literatureEchoReadFields)
+	keys := make([]string, 0, len(hashIDs)*per)
+	for _, h := range hashIDs {
+		prefix := c.buildKeyPrefix(h)
+		for _, f := range literatureEchoReadFields {
+			keys = append(keys, prefix+f)
+		}
+	}
+
+	// Chunked so one MGET never carries the whole corpus.
+	const chunk = 3000
+	values := make([]interface{}, 0, len(keys))
+	for start := 0; start < len(keys); start += chunk {
+		end := start + chunk
+		if end > len(keys) {
+			end = len(keys)
+		}
+		got, err := c.client.MGet(ctx, keys[start:end]...).Result()
+		if err != nil {
+			return nil, fmt.Errorf("mget: %w", err)
+		}
+		values = append(values, got...)
+	}
+
+	// A nil slot is an absent key. A present key holding "" is still an echo
+	// and still goes, so presence — not the value — decides.
+	get := func(i int) (string, bool) {
+		if i >= len(values) || values[i] == nil {
+			return "", false
+		}
+		s, ok := values[i].(string)
+		return s, ok
+	}
+
+	type candidate struct {
+		hashID     string
+		hasAnilist bool
+		echoes     []string
+	}
+	var cands []candidate
+	var probe []string // candidates whose anilistid needs their cids/ key-set
+	for i, h := range hashIDs {
+		base := i * per
+		domain, _ := get(base)
+		fileType, _ := get(base + 1)
+		if domain != "literature" || fileType != "card" {
+			continue
+		}
+		cand := candidate{hashID: h}
+		_, cand.hasAnilist = get(base + 2)
+		for j, f := range literatureCardEchoFields {
+			if _, ok := get(base + 3 + j); ok {
+				cand.echoes = append(cand.echoes, f)
+			}
+		}
+		if !cand.hasAnilist && len(cand.echoes) == 0 {
+			continue
+		}
+		if cand.hasAnilist {
+			probe = append(probe, h)
+		}
+		cands = append(cands, cand)
+	}
+
+	// Pass 2: the field-name index of only the cards carrying an `anilistid`
+	// — the `cids/` members are field NAMES, so the index is where they are
+	// listed. Pipelined per chunk; still no SCAN.
+	//
+	// A card with no index (never touched since before the index existed, and
+	// missed by the startup WarmFieldIndexes pass) reads as an empty set and
+	// keeps its `anilistid`: proving it a site card would need exactly the
+	// per-record SCAN this sweep refuses, and a stamp left in place is the
+	// safe direction.
+	siteCard := make(map[string]bool, len(probe))
+	for start := 0; start < len(probe); start += mgetBatch {
+		end := start + mgetBatch
+		if end > len(probe) {
+			end = len(probe)
+		}
+		pipe := c.client.Pipeline()
+		cmds := make([]*redis.StringSliceCmd, 0, end-start)
+		for _, h := range probe[start:end] {
+			cmds = append(cmds, pipe.SMembers(ctx, c.buildFieldsKey(h)))
+		}
+		if _, err := pipe.Exec(ctx); err != nil && err != redis.Nil {
+			return nil, fmt.Errorf("smembers fields: %w", err)
+		}
+		for k, cmd := range cmds {
+			fields, err := cmd.Result()
+			if err != nil && err != redis.Nil {
+				return nil, fmt.Errorf("smembers fields %s: %w", probe[start+k], err)
+			}
+			siteCard[probe[start+k]] = isSiteCard(fields)
+		}
+	}
+
+	plans := make([]literatureEchoPlan, 0, len(cands))
+	for _, cand := range cands {
+		var fields []string
+		if cand.hasAnilist && siteCard[cand.hashID] {
+			fields = append(fields, "anilistid")
+		}
+		fields = append(fields, cand.echoes...)
+		if len(fields) > 0 {
+			plans = append(plans, literatureEchoPlan{hashID: cand.hashID, fields: fields})
+		}
+	}
+	return plans, nil
+}
+
+// SweepLiteratureEchoesWithTimeout is the convenience wrapper used by the API
+// handler. Generous timeout: the read phase is batched, but the write phase is
+// one round-trip per deleted field.
+func (c *Client) SweepLiteratureEchoesWithTimeout(apply bool) (LiteratureEchoSweep, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
+	defer cancel()
+	return c.SweepLiteratureEchoes(ctx, apply)
+}

internal/storage/literature_echo_sweep_test.go

@@ -0,0 +1,249 @@
+package storage
+
+import (
+	"context"
+	"encoding/base32"
+	"encoding/binary"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+// Pinned from meta-read `src/card_cid.rs` — literals, not round-trips.
+const (
+	literatureAnchorCardCID = "bagdsaaaua5qw42lmnfzxi3lbnztwcorrga2tonzy" // ("anilist", "manga:105778")
+	literatureSiteCardCID   = "bagdsaabybrwwc3thmfsgk6bon5zgol3nmfxgoyjpmiygenzsgftgmlldgm4dqljugq4dmllbmeygmlldgjrdaytcgmzdcnjrgi"
+	// A non-card CID a card may also carry.
+	literatureContentCID = "bagacbabaec7v3fu2ygzh3e2sybg3fbzmisry2hbtpmck6vx3yftea6vzq35r4"
+)
+
+// mintCardCID encodes a card locator the way meta-feeder-sdk
+// `compute_card_cid` does. Asserted against the pinned literals before use.
+func mintCardCID(source, id string) string {
+	digest := binary.AppendUvarint(nil, uint64(len(source)))
+	digest = append(digest, source...)
+	digest = append(digest, id...)
+	wire := []byte{0x01}
+	wire = binary.AppendUvarint(wire, 0x1007)
+	wire = append(wire, 0x00)
+	wire = binary.AppendUvarint(wire, uint64(len(digest)))
+	wire = append(wire, digest...)
+	return "b" + strings.ToLower(base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(wire))
+}
+
+func TestIsSiteFormCardLocator(t *testing.T) {
+	if got := mintCardCID("anilist", "manga:105778"); got != literatureAnchorCardCID {
+		t.Fatalf("test encoder drifted: %s != %s", got, literatureAnchorCardCID)
+	}
+	if got := mintCardCID("mangadex.org", "/manga/b0b721ff-c388-4486-aa0f-c2b0bb321512"); got != literatureSiteCardCID {
+		t.Fatalf("test encoder drifted: %s != %s", got, literatureSiteCardCID)
+	}
+
+	for _, tc := range []struct {
+		name string
+		cid  string
+		want bool
+	}{
+		{"anilist anchor (golden)", literatureAnchorCardCID, false},
+		{"mangadex site (golden)", literatureSiteCardCID, true},
+		{"openlibrary anchor", mintCardCID("openlibrary", "OL45804W"), false},
+		{"another site", mintCardCID("weebcentral.com", "/series/01J76XY/chainsaw-man"), true},
+		// Not an anchor source, but not host-shaped either: meta-read reads it
+		// as an id-bag key, so it must not be treated as a site.
+		{"dotless unknown source", mintCardCID("suwayomi", "42"), false},
+		{"content CID", literatureContentCID, false},
+		{"title key", "title:chainsaw man", false},
+	} {
+		if got := isSiteFormCardLocator(tc.cid); got != tc.want {
+			t.Errorf("%s: isSiteFormCardLocator = %v, want %v", tc.name, got, tc.want)
+		}
+	}
+}
+
+// seedLiteratureCorpus writes one record per rule the sweep has to honour.
+func seedLiteratureCorpus(t *testing.T, c *Client) {
+	t.Helper()
+
+	// A site card carrying every echo: all of it goes.
+	seedRecord(t, c, "site-card", map[string]string{
+		"domain":                        "literature",
+		"fileType":                      "card",
+		"title":                         "Chainsaw Man",
+		"cids/" + literatureSiteCardCID: "true",
+		"anilistid":                     "105778",
+		"workcid":                       literatureSiteCardCID,
+		"chapterNumber":                 "12",
+		"volumeNumber":                  "2",
+		"chapterStart":                  "1",
+		"chapterEnd":                    "20",
+	})
+	// An anchor card: its anilistid is its identity and stays; the position
+	// echo and the workcid still go.
+	seedRecord(t, c, "anchor-card", map[string]string{
+		"domain":                          "literature",
+		"fileType":                        "card",
+		"title":                           "Chainsaw Man",
+		"cids/" + literatureAnchorCardCID: "true",
+		"anilistid":                       "105778",
+		"workcid":                         literatureAnchorCardCID,
+		"chapterNumber":                   "3",
+	})
+	// A site card that is already clean: nothing planned.
+	seedRecord(t, c, "clean-site-card", map[string]string{
+		"domain":                        "literature",
+		"fileType":                      "card",
+		"cids/" + literatureSiteCardCID: "true",
+	})
+	// Both locator forms: which one the id belongs to is unknowable, so it
+	// stays.
+	seedRecord(t, c, "merged-card", map[string]string{
+		"domain":                          "literature",
+		"fileType":                        "card",
+		"cids/" + literatureSiteCardCID:   "true",
+		"cids/" + literatureAnchorCardCID: "true",
+		"anilistid":                       "105778",
+	})
+	// No card locator at all: not provably a site card.
+	seedRecord(t, c, "unlocated-card", map[string]string{
+		"domain":                       "literature",
+		"fileType":                     "card",
+		"cids/" + literatureContentCID: "true",
+		"anilistid":                    "105778",
+	})
+	// A stored empty value is still an echo.
+	seedRecord(t, c, "blank-echo-card", map[string]string{
+		"domain":       "literature",
+		"fileType":     "card",
+		"volumeNumber": "",
+	})
+	// A chapter is never swept, whatever it carries.
+	seedRecord(t, c, "chapter", map[string]string{
+		"domain":                       "literature",
+		"fileType":                     "archive",
+		"cids/" + literatureContentCID: "true",
+		"anilistid":                    "105778",
+		"workcid":                      literatureSiteCardCID,
+		"chapterNumber":                "12",
+	})
+	// Not literature: out of scope even though it is a card.
+	seedRecord(t, c, "screen-card", map[string]string{
+		"domain":        "screen",
+		"fileType":      "card",
+		"workcid":       literatureSiteCardCID,
+		"chapterNumber": "1",
+	})
+}
+
+func TestPlanLiteratureEchoes_ScopesToLiteratureCards(t *testing.T) {
+	c, _ := newTestClient(t, "")
+	seedLiteratureCorpus(t, c)
+
+	plans, err := c.planLiteratureEchoes(context.Background())
+	if err != nil {
+		t.Fatalf("plan: %v", err)
+	}
+	got := map[string][]string{}
+	for _, p := range plans {
+		got[p.hashID] = p.fields
+	}
+	want := map[string][]string{
+		"site-card":       {"anilistid", "workcid", "chapterNumber", "volumeNumber", "chapterStart", "chapterEnd"},
+		"anchor-card":     {"workcid", "chapterNumber"},
+		"blank-echo-card": {"volumeNumber"},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("plan =\n  %v\nwant\n  %v", got, want)
+	}
+}
+
+func TestSweepLiteratureEchoes_DryRunThenApply(t *testing.T) {
+	c, s := newTestClient(t, "mm:")
+	seedLiteratureCorpus(t, c)
+
+	wantByKey := map[string]int{
+		"anilistid":     1,
+		"workcid":       2,
+		"chapterNumber": 2,
+		"volumeNumber":  2,
+		"chapterStart":  1,
+		"chapterEnd":    1,
+	}
+
+	// Dry run: counts, and nothing written.
+	dry, err := c.SweepLiteratureEchoes(context.Background(), false)
+	if err != nil {
+		t.Fatalf("dry run: %v", err)
+	}
+	if dry.Planned != 3 || dry.Fixed != 0 {
+		t.Errorf("dry run planned/fixed = %d/%d, want 3/0", dry.Planned, dry.Fixed)
+	}
+	if !reflect.DeepEqual(dry.ByKey, wantByKey) {
+		t.Errorf("dry run byKey = %v, want %v", dry.ByKey, wantByKey)
+	}
+	if m, _ := c.GetMetadataFlat("site-card"); m["anilistid"] != "105778" {
+		t.Fatalf("dry run deleted anilistid: %v", m)
+	}
+
+	applied, err := c.SweepLiteratureEchoes(context.Background(), true)
+	if err != nil {
+		t.Fatalf("apply: %v", err)
+	}
+	if applied.Planned != 3 || applied.Fixed != 3 {
+		t.Errorf("apply planned/fixed = %d/%d, want 3/3", applied.Planned, applied.Fixed)
+	}
+	if !reflect.DeepEqual(applied.ByKey, wantByKey) {
+		t.Errorf("apply byKey = %v, want %v", applied.ByKey, wantByKey)
+	}
+
+	site, err := c.GetMetadataFlat("site-card")
+	if err != nil {
+		t.Fatalf("read site-card: %v", err)
+	}
+	for _, k := range []string{"anilistid", "workcid", "chapterNumber", "volumeNumber", "chapterStart", "chapterEnd"} {
+		if _, ok := site[k]; ok {
+			t.Errorf("site-card still carries %s", k)
+		}
+		// The flat key and its field-name index entry must both be gone, or the
+		// next read would MGET a ghost field.
+		if s.Exists("mm:file:site-card/" + k) {
+			t.Errorf("site-card flat key %s survived", k)
+		}
+		if member, _ := s.IsMember("mm:file:site-card/"+FieldsField, k); member {
+			t.Errorf("site-card field index still lists %s", k)
+		}
+	}
+	if site["title"] != "Chainsaw Man" || site["cids/"+literatureSiteCardCID] != "true" {
+		t.Errorf("site-card lost fields it should keep: %v", site)
+	}
+
+	anchor, _ := c.GetMetadataFlat("anchor-card")
+	if anchor["anilistid"] != "105778" {
+		t.Errorf("anchor-card anilistid = %q, want kept", anchor["anilistid"])
+	}
+	if _, ok := anchor["workcid"]; ok {
+		t.Errorf("anchor-card still carries workcid")
+	}
+
+	chapter, _ := c.GetMetadataFlat("chapter")
+	if chapter["anilistid"] != "105778" || chapter["workcid"] != literatureSiteCardCID || chapter["chapterNumber"] != "12" {
+		t.Errorf("chapter was touched: %v", chapter)
+	}
+	screen, _ := c.GetMetadataFlat("screen-card")
+	if screen["workcid"] != literatureSiteCardCID {
+		t.Errorf("screen-card was touched: %v", screen)
+	}
+	merged, _ := c.GetMetadataFlat("merged-card")
+	if merged["anilistid"] != "105778" {
+		t.Errorf("merged-card anilistid = %q, want kept", merged["anilistid"])
+	}
+
+	// Idempotent: the endpoint is called by hand, and a second call must find
+	// nothing — with byKey still an empty map, not nil.
+	again, err := c.SweepLiteratureEchoes(context.Background(), true)
+	if err != nil {
+		t.Fatalf("second pass: %v", err)
+	}
+	if again.Planned != 0 || again.Fixed != 0 || again.ByKey == nil || len(again.ByKey) != 0 {
+		t.Errorf("second pass = %+v, want nothing planned and an empty byKey", again)
+	}
+}

internal/storage/search_dirty.go

@@ -0,0 +1,245 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"sort"
+	"strings"
+	"time"
+)
+
+// Incremental search-index maintenance.
+//
+// # Why this exists
+//
+// The API's in-memory search index used to be rebuilt in full every 60 s:
+// GetSearchIndexTuples does a whole-keyspace SCAN plus batched MGETs, builds an
+// intermediate map of every record, then allocates a fresh []SearchTuple — all
+// while the previous index is still live serving reads. That cost is O(corpus),
+// not O(change): adding 200 records in a minute re-read every one of the other
+// ~620 000 field keys to notice them.
+//
+// Measured on a 19 622-record staging corpus (2026-08-30): SCAN was 57.8 % and
+// MGET 19.1 % of ALL Redis CPU, and ~90 % of the MGET calls plus ~48 % of the
+// SCAN calls were this loop — roughly 45 % of Redis's total work, spent
+// continuously whether or not anything changed. The Go side held 783 MB for
+// data Redis stores in 135 MB, largely because of the double copy.
+//
+// That was tolerable while the corpus was small and mostly static. It stops
+// being tolerable now that meta-core is the platform's permanent, additive
+// store: every search hit on every gateway is retained forever, so the rebuild
+// cost is a ratchet.
+//
+// # The shape
+//
+// Every write path marks its record in a dirty set; the refresh drains that set
+// and re-reads only those records. Cost becomes O(change).
+//
+// Marking rides along with the field-index maintenance every write path already
+// performs, so there is no new bookkeeping discipline to remember — if you are
+// adding a write path, the same line that keeps `__fields__` correct keeps this
+// correct.
+//
+// # Correctness
+//
+// The drain is a destructive SPOP, so a write that lands *during* a refresh is
+// either already in the drained batch or still in the set for the next tick —
+// never dropped. The cost of the race is one tick of staleness, which is well
+// inside the interval the index was already stale by.
+//
+// A refresh that fails after draining WOULD lose its batch, so drainDirty's
+// caller re-marks on error (see MarkDirty / the API's refreshIncremental).
+//
+// ⚠ **The destructive drain assumes ONE index consumer per Redis.** Two
+// meta-core processes sharing a keyspace would steal each other's marks, and
+// each would end up with an index missing whatever the other drained. That is
+// fine today — multi-instance leader election was deprecated and the dev/prod
+// stacks run a single meta-core — but it is the assumption to revisit first if
+// a second instance is ever pointed at the same Redis. A per-consumer dirty key
+// (`file:__dirty__:<consumer>`) is the shape that would fix it.
+//
+// The API's periodic full reconcile (searchIndexReconcileEvery) is the backstop
+// for both this and for a write path that forgets to mark: a missed mark costs
+// staleness until the next reconcile, never permanent divergence.
+
+// dirtyField is the reserved key holding the set of record ids whose metadata
+// changed since the last search-index refresh. It sits under the same `file:`
+// namespace as `__index__` and is likewise not a record.
+const dirtyField = "file:__dirty__"
+
+// dirtyDrainCap bounds one incremental refresh. A burst larger than this is
+// drained over several ticks rather than in one long-held pass — the point of
+// the change is to keep any single refresh cheap. Sized well above a normal
+// search-persist flush (which writes at most a few hundred records).
+const dirtyDrainCap = 5000
+
+// buildDirtyKey constructs the key for the dirty-record set.
+func (c *Client) buildDirtyKey() string {
+	return c.buildKey(dirtyField)
+}
+
+// markDirtyLocked records that hashID's metadata changed. Caller must hold c.mu.
+//
+// Best-effort by design: a failure here costs one record its incremental
+// refresh, and the periodic full rebuild still repairs it. Failing the caller's
+// write instead would trade a stale index entry for a lost write, which is
+// strictly worse.
+func (c *Client) markDirtyLocked(ctx context.Context, hashID string) {
+	if hashID == "" {
+		return
+	}
+	if err := c.client.SAdd(ctx, c.buildDirtyKey(), hashID).Err(); err != nil {
+		log.Printf("[STORAGE] dirty-mark failed for %s: %v (index repairs on the next full rebuild)", hashID, err)
+	}
+}
+
+// MarkDirty records that hashID needs re-indexing. Exported for the API layer,
+// which re-marks a batch whose refresh failed after the drain.
+func (c *Client) MarkDirty(hashIDs ...string) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	if c.client == nil || len(hashIDs) == 0 {
+		return
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	members := make([]interface{}, 0, len(hashIDs))
+	for _, h := range hashIDs {
+		if h != "" {
+			members = append(members, h)
+		}
+	}
+	if len(members) == 0 {
+		return
+	}
+	if err := c.client.SAdd(ctx, c.buildDirtyKey(), members...).Err(); err != nil {
+		log.Printf("[STORAGE] dirty re-mark failed for %d records: %v", len(members), err)
+	}
+}
+
+// DrainDirty removes and returns up to dirtyDrainCap record ids from the dirty
+// set. `more` reports whether entries remain, so the caller can schedule
+// another pass instead of waiting a full interval to catch up on a burst.
+//
+// Destructive on purpose: SPOP makes concurrent refreshes disjoint and stops a
+// record being re-read every tick forever. The caller owns the drained ids
+// until it has indexed them — on failure it must MarkDirty them again.
+func (c *Client) DrainDirty() (ids []string, more bool, err error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return nil, false, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	key := c.buildDirtyKey()
+	ids, err = c.client.SPopN(ctx, key, dirtyDrainCap).Result()
+	if err != nil {
+		return nil, false, fmt.Errorf("spop dirty: %w", err)
+	}
+	if len(ids) < dirtyDrainCap {
+		return ids, false, nil
+	}
+	remaining, err := c.client.SCard(ctx, key).Result()
+	if err != nil {
+		// We have the batch; not knowing the remainder just means the next
+		// tick picks it up on schedule.
+		return ids, false, nil
+	}
+	return ids, remaining > 0, nil
+}
+
+// GetSearchIndexTuplesFor reads the search tuples for a specific set of records
+// — the incremental counterpart to GetSearchIndexTuples.
+//
+// Reads go through the per-record field index (GetMetadataFlat), so this is two
+// round-trips per record rather than a keyspace scan. That trade is what makes
+// it O(change): it beats the full pass whenever the changed set is a small
+// fraction of the corpus, and the caller bounds the batch (dirtyDrainCap).
+//
+// A record present in the dirty set but absent from storage was deleted; it is
+// reported in `gone` so the caller can evict it from the index rather than
+// leaving a tombstone that still answers searches.
+func (c *Client) GetSearchIndexTuplesFor(hashIDs []string) (tuples []SearchTuple, gone []string, err error) {
+	if len(hashIDs) == 0 {
+		return nil, nil, nil
+	}
+
+	excluded := indexExcludePrefixes()
+	tuples = make([]SearchTuple, 0, len(hashIDs))
+
+	for _, hashID := range hashIDs {
+		fields, ferr := c.GetMetadataFlat(hashID)
+		if ferr != nil {
+			// Re-mark so the record is retried rather than silently missing
+			// from the index until the next full rebuild.
+			c.MarkDirty(hashID)
+			log.Printf("[STORAGE] incremental index read failed for %s: %v", hashID, ferr)
+			continue
+		}
+		if len(fields) == 0 {
+			gone = append(gone, hashID)
+			continue
+		}
+		for field := range fields {
+			if hasAnyPrefix(field, excluded) {
+				delete(fields, field)
+			}
+		}
+		tuples = append(tuples, SearchTuple{
+			HashID:   hashID,
+			Haystack: buildHaystack(fields),
+			Fields:   fields,
+		})
+	}
+	return tuples, gone, nil
+}
+
+// buildHaystack folds a record's searchable text fields into one lowercased
+// blob. Shared by the full and incremental index reads so the two can never
+// disagree about what is searchable — a drift there would make a record's
+// matchability depend on which path happened to index it.
+//
+// Beyond the flat fields it folds in every `titles/<lang3>/<name>` member's
+// name (METADATA_KEYS.md §3): the name lives in the key and the value is the
+// sentinel "true", so a search for an alternative title (`3 percent`) finds the
+// record whose `title` is `3%`.
+func buildHaystack(fields map[string]string) string {
+	var sb strings.Builder
+	for _, f := range searchIndexFields {
+		if v, ok := fields[f]; ok && v != "" {
+			sb.WriteString(strings.ToLower(v))
+			sb.WriteByte('\n')
+		}
+	}
+	for _, name := range titleMemberNames(fields) {
+		sb.WriteString(strings.ToLower(name))
+		sb.WriteByte('\n')
+	}
+	return sb.String()
+}
+
+// titleMemberNames returns the names of a record's `titles/<lang3>/<name>`
+// key-set members, with the `∕` (U+2215) a writer substitutes for `/` mapped
+// back. Sorted: the fields map has no order, and the full and incremental
+// builds must produce byte-identical haystacks.
+func titleMemberNames(fields map[string]string) []string {
+	var names []string
+	for k, v := range fields {
+		rest, ok := strings.CutPrefix(k, "titles/")
+		if !ok || v == "" || v == "false" {
+			continue
+		}
+		_, name, ok := strings.Cut(rest, "/")
+		if !ok || name == "" {
+			continue
+		}
+		names = append(names, strings.ReplaceAll(name, "\u2215", "/"))
+	}
+	sort.Strings(names)
+	return names
+}

internal/storage/search_dirty_test.go

@@ -0,0 +1,230 @@
+package storage
+
+import (
+	"context"
+	"sort"
+	"testing"
+)
+
+// Tests for incremental search-index maintenance (search_dirty.go).
+//
+// The dirty set is derived state on the hot write path, which makes its failure
+// mode the dangerous kind: a MISSING mark doesn't error, it just leaves the
+// search index quietly serving a stale copy of that record until someone
+// triggers a full rebuild. So the property worth pinning is coverage — every
+// path that changes what a search would match must mark — and that is what the
+// bulk of these tests assert, one write path at a time.
+//
+// The second property is that a delete is a mark too, not an unmark: the
+// refresh has to LEARN the record is gone in order to evict it. Marking on
+// delete is counter-intuitive enough to be worth a test of its own.
+
+func dirtyMembers(t *testing.T, c *Client) []string {
+	t.Helper()
+	got, err := c.client.SMembers(context.Background(), c.buildDirtyKey()).Result()
+	if err != nil {
+		t.Fatalf("smembers dirty: %v", err)
+	}
+	sort.Strings(got)
+	return got
+}
+
+func clearDirty(t *testing.T, c *Client) {
+	t.Helper()
+	if err := c.client.Del(context.Background(), c.buildDirtyKey()).Err(); err != nil {
+		t.Fatalf("del dirty: %v", err)
+	}
+}
+
+// Every write path must mark. A path that doesn't leaves the index serving a
+// stale record with no error anywhere.
+func TestDirty_EveryWritePathMarks(t *testing.T) {
+	forEachPrefix(t, func(t *testing.T, c *Client) {
+		cases := []struct {
+			name  string
+			id    string
+			write func(id string) error
+		}{
+			{"SetMetadataFlat", "r-set", func(id string) error {
+				return c.SetMetadataFlat(id, map[string]string{"title": "A"})
+			}},
+			{"SetProperty", "r-prop", func(id string) error {
+				return c.SetProperty(id, "title", "B")
+			}},
+			{"MergeMetadataFlat", "r-merge", func(id string) error {
+				_, err := c.MergeMetadataFlat(id, map[string]string{"title": "C"})
+				return err
+			}},
+			{"AddToSet", "r-add", func(id string) error {
+				_, err := c.AddToSet(id, "tags", "x")
+				return err
+			}},
+		}
+		for _, tc := range cases {
+			t.Run(tc.name, func(t *testing.T) {
+				clearDirty(t, c)
+				if err := tc.write(tc.id); err != nil {
+					t.Fatalf("%s: %v", tc.name, err)
+				}
+				got := dirtyMembers(t, c)
+				if len(got) != 1 || got[0] != tc.id {
+					t.Fatalf("%s must mark %q dirty, got %v", tc.name, tc.id, got)
+				}
+			})
+		}
+	})
+}
+
+// RemoveFromSet's non-empty branch changes a field's VALUE without changing the
+// field-name index, so it is the one path that a mark riding on field-index
+// maintenance would have missed. Pinned explicitly for that reason.
+func TestDirty_RemoveFromSetMarksEvenWhenTheFieldSurvives(t *testing.T) {
+	forEachPrefix(t, func(t *testing.T, c *Client) {
+		const id = "r-rem"
+		for _, v := range []string{"x", "y"} {
+			if _, err := c.AddToSet(id, "tags", v); err != nil {
+				t.Fatalf("AddToSet: %v", err)
+			}
+		}
+		clearDirty(t, c)
+
+		if _, err := c.RemoveFromSet(id, "tags", "x"); err != nil {
+			t.Fatalf("RemoveFromSet: %v", err)
+		}
+		// `tags` still exists (y remains) — no field-index change, but the
+		// searchable value changed.
+		if got := dirtyMembers(t, c); len(got) != 1 || got[0] != id {
+			t.Fatalf("a value-only change must still mark dirty, got %v", got)
+		}
+	})
+}
+
+// A delete MARKS rather than unmarks: the refresh must read the record, find it
+// gone, and evict it. Unmarking would leave a deleted record answering searches
+// until the next full rebuild.
+func TestDirty_DeletesMarkSoTheRefreshCanEvict(t *testing.T) {
+	forEachPrefix(t, func(t *testing.T, c *Client) {
+		const id = "r-del"
+		if err := c.SetMetadataFlat(id, map[string]string{"title": "Doomed"}); err != nil {
+			t.Fatalf("SetMetadataFlat: %v", err)
+		}
+		clearDirty(t, c)
+
+		if _, err := c.DeleteMetadata(id); err != nil {
+			t.Fatalf("DeleteMetadata: %v", err)
+		}
+		if got := dirtyMembers(t, c); len(got) != 1 || got[0] != id {
+			t.Fatalf("a delete must mark dirty so the index evicts it, got %v", got)
+		}
+
+		// …and the incremental read reports it as gone rather than as an error
+		// or an empty-but-present tuple.
+		tuples, gone, err := c.GetSearchIndexTuplesFor([]string{id})
+		if err != nil {
+			t.Fatalf("GetSearchIndexTuplesFor: %v", err)
+		}
+		if len(tuples) != 0 {
+			t.Fatalf("a deleted record must produce no tuple, got %d", len(tuples))
+		}
+		if len(gone) != 1 || gone[0] != id {
+			t.Fatalf("a deleted record must be reported gone, got %v", gone)
+		}
+	})
+}
+
+// The drain is destructive so concurrent refreshes stay disjoint and a record
+// isn't re-read every tick forever. The caller owns what it drained.
+func TestDirty_DrainIsDestructive(t *testing.T) {
+	forEachPrefix(t, func(t *testing.T, c *Client) {
+		clearDirty(t, c)
+		c.MarkDirty("a", "b", "c")
+
+		ids, more, err := c.DrainDirty()
+		if err != nil {
+			t.Fatalf("DrainDirty: %v", err)
+		}
+		sort.Strings(ids)
+		if len(ids) != 3 {
+			t.Fatalf("expected 3 drained ids, got %v", ids)
+		}
+		if more {
+			t.Fatal("a fully-drained set must not report more")
+		}
+		if got := dirtyMembers(t, c); len(got) != 0 {
+			t.Fatalf("drain must empty the set, got %v", got)
+		}
+
+		// A second drain is empty, not an error — the steady state when nothing
+		// has been written since the last tick.
+		ids, _, err = c.DrainDirty()
+		if err != nil || len(ids) != 0 {
+			t.Fatalf("draining an empty set must be a clean no-op, got %v / %v", ids, err)
+		}
+	})
+}
+
+// The incremental read must produce tuples indistinguishable from the full
+// rebuild's — same haystack, same fields, same exclusions. A drift here would
+// make a record's matchability depend on which path happened to index it, which
+// is invisible until someone searches for the one term that differs.
+func TestDirty_IncrementalTuplesMatchTheFullRebuild(t *testing.T) {
+	forEachPrefix(t, func(t *testing.T, c *Client) {
+		const id = "r-parity"
+		if err := c.SetMetadataFlat(id, map[string]string{
+			"title":                   "Parity Release",
+			"fileName":                "parity.s01e01.mkv",
+			"fileType":                "video",
+			"titles/eng/3 Percent":    "true",
+			"titles/fra/3 Pourcent":   "true",
+			"categories/XXX":          "true",
+			"categories/newznab/5070": "true",
+		}); err != nil {
+			t.Fatalf("SetMetadataFlat: %v", err)
+		}
+
+		full := tuplesByHashID(t, c)[id]
+		incr, gone, err := c.GetSearchIndexTuplesFor([]string{id})
+		if err != nil {
+			t.Fatalf("GetSearchIndexTuplesFor: %v", err)
+		}
+		if len(gone) != 0 || len(incr) != 1 {
+			t.Fatalf("expected exactly one live tuple, got %d live / %d gone", len(incr), len(gone))
+		}
+
+		if incr[0].Haystack != full.Haystack {
+			t.Errorf("haystack drift:\n incremental %q\n full        %q", incr[0].Haystack, full.Haystack)
+		}
+		if len(incr[0].Fields) != len(full.Fields) {
+			t.Errorf("field-count drift: incremental %d, full %d", len(incr[0].Fields), len(full.Fields))
+		}
+		for k, v := range full.Fields {
+			if incr[0].Fields[k] != v {
+				t.Errorf("field %q drift: incremental %q, full %q", k, incr[0].Fields[k], v)
+			}
+		}
+		// The index projection must apply on both paths.
+		if _, ok := incr[0].Fields["categories/newznab/5070"]; ok {
+			t.Error("the incremental path must honour the index exclusion list too")
+		}
+		if _, ok := incr[0].Fields["categories/XXX"]; !ok {
+			t.Error("the incremental path must keep the adult-filter category")
+		}
+	})
+}
+
+// A `titles/<lang3>/<name>` member contributes its NAME (the key), never its
+// "true" value, and the `∕` a writer substituted for `/` reads back as `/`.
+func TestBuildHaystack_FoldsTitleMemberNames(t *testing.T) {
+	got := buildHaystack(map[string]string{
+		"title":                     "3%",
+		"titles/fra/3 Pourcent":     "true",
+		"titles/eng/3 Percent":      "true",
+		"titles/und/Fate\u2215Zero": "true",
+		"titles/eng":                "Retired Scalar",
+		"titles/eng/":               "true",
+	})
+	want := "3%\n3 percent\n3 pourcent\nfate/zero\n"
+	if got != want {
+		t.Errorf("haystack = %q, want %q", got, want)
+	}
+}

internal/storage/search_index_exclude_test.go

@@ -0,0 +1,116 @@
+package storage
+
+import (
+	"testing"
+)
+
+// Tests for the search-index field projection (GetSearchIndexTuples +
+// indexExcludePrefixes).
+//
+// The projection narrows the in-memory index only — Redis keeps every field and
+// every per-record read still returns it. What has to be pinned is the boundary
+// between the two, because getting it wrong in either direction is silent:
+// exclude too little and the index keeps paying for fields nothing reads;
+// exclude too much and a record served *from the index* comes back missing a
+// field a downstream consumer depends on.
+//
+// The specific hazard the default guards is adult-content filtering:
+// `categories/XXX` is the server-side enforcement point (meta-search's
+// `query_eval::fields_are_adult`, meta-gateway's `cards::fields_are_adult`),
+// and `exclude_adult` defaults to ON. Excluding the whole `categories/` family
+// would make every index-served record read as non-adult and the filter would
+// fail OPEN — so the default must keep `categories/XXX` while dropping the
+// reader-less `categories/newznab/` mirror.
+
+func tuplesByHashID(t *testing.T, c *Client) map[string]SearchTuple {
+	t.Helper()
+	got, err := c.GetSearchIndexTuples()
+	if err != nil {
+		t.Fatalf("GetSearchIndexTuples: %v", err)
+	}
+	out := make(map[string]SearchTuple, len(got))
+	for _, tu := range got {
+		out[tu.HashID] = tu
+	}
+	return out
+}
+
+func TestSearchIndex_ExcludesNewznabCategoriesButKeepsTheRest(t *testing.T) {
+	forEachPrefix(t, func(t *testing.T, c *Client) {
+		const id = "root-1"
+		if err := c.SetMetadataFlat(id, map[string]string{
+			"title":                   "Some Release",
+			"fileType":                "video",
+			"categories/TV/Anime":     "true",
+			"categories/XXX":          "true",
+			"categories/newznab/5070": "true",
+			"categories/newznab/2040": "true",
+		}); err != nil {
+			t.Fatalf("SetMetadataFlat: %v", err)
+		}
+
+		fields := tuplesByHashID(t, c)[id].Fields
+		if fields == nil {
+			t.Fatal("record missing from the search index")
+		}
+
+		for _, excluded := range []string{"categories/newznab/5070", "categories/newznab/2040"} {
+			if _, ok := fields[excluded]; ok {
+				t.Errorf("%s must not be indexed — it is a reader-less mirror vocabulary", excluded)
+			}
+		}
+		// The load-bearing ones must survive. XXX especially: without it the
+		// adult filter fails open on every index-served record.
+		for _, kept := range []string{"categories/XXX", "categories/TV/Anime", "title", "fileType"} {
+			if _, ok := fields[kept]; !ok {
+				t.Errorf("%s must stay in the index", kept)
+			}
+		}
+
+		// The store itself is untouched — the projection is index-only.
+		stored, err := c.GetMetadataFlat(id)
+		if err != nil {
+			t.Fatalf("GetMetadataFlat: %v", err)
+		}
+		if _, ok := stored["categories/newznab/5070"]; !ok {
+			t.Error("an index-excluded field must still be stored and readable per-record")
+		}
+	})
+}
+
+func TestIndexExcludePrefixes_EnvOverride(t *testing.T) {
+	if got := indexExcludePrefixes(); len(got) != 1 || got[0] != "categories/newznab/" {
+		t.Fatalf("unset env must yield the default, got %v", got)
+	}
+
+	t.Setenv("META_CORE_INDEX_EXCLUDE_PREFIXES", "foo/, bar/ ,")
+	got := indexExcludePrefixes()
+	if len(got) != 2 || got[0] != "foo/" || got[1] != "bar/" {
+		t.Fatalf("override must trim and drop blanks, got %v", got)
+	}
+
+	// An explicitly empty value is the escape hatch: index everything.
+	t.Setenv("META_CORE_INDEX_EXCLUDE_PREFIXES", "")
+	if got := indexExcludePrefixes(); len(got) != 0 {
+		t.Fatalf("an empty override must disable exclusion, got %v", got)
+	}
+}
+
+func TestHasAnyPrefix(t *testing.T) {
+	prefixes := []string{"categories/newznab/", "tmp/"}
+	cases := map[string]bool{
+		"categories/newznab/5070": true,
+		"tmp/scratch":             true,
+		"categories/XXX":          false,
+		"categories/newznab":      false, // the family root is not the mirror
+		"title":                   false,
+	}
+	for field, want := range cases {
+		if got := hasAnyPrefix(field, prefixes); got != want {
+			t.Errorf("hasAnyPrefix(%q) = %v, want %v", field, got, want)
+		}
+	}
+	if hasAnyPrefix("anything", nil) {
+		t.Error("an empty prefix list must exclude nothing")
+	}
+}

internal/storage/stats.go

@@ -0,0 +1,52 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+// CountRoots returns the number of metadata roots in the file index.
+//
+// SCARD, not SMEMBERS: GetAllHashIDs ships every member over the wire (~3MB
+// and rising on an 88k-record box) just so the caller can take len(). A
+// dashboard tile that polls needs the number, never the list.
+func (c *Client) CountRoots() (int64, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return 0, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	n, err := c.client.SCard(ctx, c.buildIndexKey()).Result()
+	if err != nil {
+		return 0, fmt.Errorf("scard failed: %w", err)
+	}
+	return n, nil
+}
+
+// CountKeys returns DBSIZE — every key in the Redis database, not just the
+// ones meta-core owns. It is the denominator for "how much of Redis is
+// records": ~3.1M keys against ~89k roots means the flat per-field keys
+// (file:{root}/{field}) dominate, which is expected.
+func (c *Client) CountKeys() (int64, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return 0, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	n, err := c.client.DBSize(ctx).Result()
+	if err != nil {
+		return 0, fmt.Errorf("dbsize failed: %w", err)
+	}
+	return n, nil
+}

internal/storage/udl.go

@@ -17,6 +17,7 @@ package storage
 //	udl:rec:<uid>/<cid>/<key>       HASH { record, version, ts, value? }
 //	udl:idx:user:<uid>:key:<key>    SET of <cid>   -> active_for_user_key (My List, Continue Watching)
 //	udl:idx:user:<uid>:cid:<cid>    SET of <key>   -> list_for_user_cid
+//	udl:idx:user:<uid>:cids         SET of <cid>   -> whole-profile export (recovery)
 //	udl:idx:cid:<cid>:key:<key>     SET of <uid>   -> aggregate
 //	udl:idx:cid:<cid>:users         SET of <uid>   -> uids_for_cid
 //
@@ -27,7 +28,9 @@ package storage
 import (
 	"context"
 	"fmt"
+	"sort"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/redis/go-redis/v9"
@@ -66,11 +69,24 @@ func udlIdxUserCid(uid, cid string) string { return fmt.Sprintf("udl:idx:user:%s
 func udlIdxCidKey(cid, key string) string  { return fmt.Sprintf("udl:idx:cid:%s:key:%s", cid, key) }
 func udlIdxCidUsers(cid string) string      { return fmt.Sprintf("udl:idx:cid:%s:users", cid) }
 
+// udlIdxUserCids is the set of every cid a uid has ANY record for — the one
+// index that makes "export this whole profile" a set read instead of a
+// keyspace scan.
+//
+// The other four indexes each answer a question with one coordinate already
+// known (a key, a cid). Cross-instance recovery knows neither: it has a uid and
+// nothing else. Without this set the only ways to enumerate a profile are to
+// iterate the hardcoded key list — which silently misses any key added later —
+// or to SCAN `udl:rec:<uid>/*`, which is the full-keyspace-read pathology that
+// already made `/api/udl/users/stats` admin-only.
+func udlIdxUserCids(uid string) string { return fmt.Sprintf("udl:idx:user:%s:cids", uid) }
+
 // udlUpsertScript performs the version-gated upsert + index maintenance
 // atomically. Accepts (returns 1) only when the incoming version strictly
 // exceeds the stored one; otherwise returns 0 (stale).
 //
 //	KEYS: 1=cell 2=idx:user:key 3=idx:user:cid 4=idx:cid:key 5=idx:cid:users
+//	      6=idx:user:cids
 //	ARGV: 1=version 2=ts 3=record 4=value 5=hasValue("1"/"0")
 //	      6=cid 7=key 8=uid 9=tombstone("1"/"0")
 //
@@ -78,9 +94,16 @@ func udlIdxCidUsers(cid string) string      { return fmt.Sprintf("udl:idx:cid:%s
 // would let an older write resurrect the value — but it SREMs the cid from the
 // user+key index. That index is what `active_for_user_key` returns, so leaving
 // deleted cids in it means every My List / Continue Watching read carries every
-// title ever un-liked or finished, forever. The other three indexes are left
+// title ever un-liked or finished, forever. The other four indexes are left
 // alone: they answer "who has an opinion about this cid", where a tombstone is
 // still an answer.
+//
+// ⚠ `idx:user:cids` (KEYS[6]) in particular must NEVER be pruned on a
+// tombstone, even though it looks symmetric with KEYS[2]. It is the export
+// index: a cid dropped from it is a cid whose tombstone never travels, and a
+// tombstone that does not travel is exactly how an un-liked title comes back
+// from the dead on the other box — the peer still holds the older `like` at a
+// lower version, and with no tombstone to beat it, nothing ever supersedes it.
 var udlUpsertScript = redis.NewScript(`
 local stored = redis.call('HGET', KEYS[1], 'version')
 if stored and tonumber(stored) >= tonumber(ARGV[1]) then
@@ -100,6 +123,7 @@ end
 redis.call('SADD', KEYS[3], ARGV[7])
 redis.call('SADD', KEYS[4], ARGV[8])
 redis.call('SADD', KEYS[5], ARGV[8])
+redis.call('SADD', KEYS[6], ARGV[6])
 return 1
 `)
 
@@ -126,6 +150,7 @@ func (c *Client) UDLUpsertIfNewer(uid, cid, key string, version, ts int64, recor
 		c.buildKey(udlIdxUserCid(uid, cid)),
 		c.buildKey(udlIdxCidKey(cid, key)),
 		c.buildKey(udlIdxCidUsers(cid)),
+		c.buildKey(udlIdxUserCids(uid)),
 	}
 	hv := "0"
 	if hasValue {
@@ -250,6 +275,160 @@ func (c *Client) UDLListUserCid(uid, cid string) ([]UDLUserCidEntry, error) {
 	return out, nil
 }
 
+// UDLUserAllEntry is one row of a whole-profile export.
+type UDLUserAllEntry struct {
+	Cid     string `json:"cid"`
+	Key     string `json:"key"`
+	Record  string `json:"record"`
+	Version int64  `json:"version"`
+	Ts      int64  `json:"ts"`
+}
+
+// UDLAllForUser returns every cell a uid owns, for cross-instance recovery.
+//
+// Ordered by cid (sorted, so paging is stable across calls even though the
+// underlying index is a Redis SET), starting strictly after `afterCid`. A cid's
+// keys are never split across a page: the page ends on a cid boundary once
+// `limit` rows have been emitted, and `nextCid` is the last cid included — pass
+// it back as `afterCid` to continue. `nextCid` is empty when the export is
+// complete.
+//
+// Tombstones are included. They are the CRDT state that stops a deleted value
+// resurrecting on the box that receives this export, so omitting them would
+// make recovery actively wrong rather than merely incomplete.
+func (c *Client) UDLAllForUser(uid, afterCid string, limit int) ([]UDLUserAllEntry, string, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return nil, "", fmt.Errorf("not connected")
+	}
+	if limit <= 0 {
+		limit = 1000
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+
+	cids, err := c.client.SMembers(ctx, c.buildKey(udlIdxUserCids(uid))).Result()
+	if err != nil {
+		return nil, "", fmt.Errorf("smembers failed: %w", err)
+	}
+	sort.Strings(cids)
+
+	out := make([]UDLUserAllEntry, 0, limit)
+	nextCid := ""
+	for _, cid := range cids {
+		if afterCid != "" && cid <= afterCid {
+			continue
+		}
+		if len(out) >= limit {
+			nextCid = out[len(out)-1].Cid
+			break
+		}
+		keys, err := c.client.SMembers(ctx, c.buildKey(udlIdxUserCid(uid, cid))).Result()
+		if err != nil {
+			return nil, "", fmt.Errorf("smembers failed: %w", err)
+		}
+		sort.Strings(keys)
+		for _, key := range keys {
+			cell, ok, err := c.udlReadCell(ctx, udlRecKey(uid, cid, key))
+			if err != nil {
+				return nil, "", err
+			}
+			if !ok {
+				continue
+			}
+			out = append(out, UDLUserAllEntry{
+				Cid: cid, Key: key, Record: cell.Record, Version: cell.Version, Ts: cell.Ts,
+			})
+		}
+	}
+	return out, nextCid, nil
+}
+
+// UDLCountUserCids is the number of distinct cids a uid holds records for.
+//
+// O(1) (a Redis SCARD), which is what makes it usable as a per-push quota
+// check on the gateway mirror — a quota that cost a keyspace walk would be a
+// denial-of-service in its own right. Counts cids rather than cells because
+// that is what the index holds; a profile is bounded by the titles it has
+// touched, not by how many keys it has per title.
+func (c *Client) UDLCountUserCids(uid string) (int64, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	if c.client == nil {
+		return 0, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	n, err := c.client.SCard(ctx, c.buildKey(udlIdxUserCids(uid))).Result()
+	if err != nil {
+		return 0, fmt.Errorf("scard failed: %w", err)
+	}
+	return n, nil
+}
+
+// UDLBackfillUserCids rebuilds the `idx:user:<uid>:cids` sets for data written
+// before that index existed, and reports how many cids it added.
+//
+// One-shot: the upsert script maintains the set from now on. It is a SCAN, but
+// a targeted one (`udl:idx:user:*:cid:*`, which is one key per (uid,cid), not
+// per record) run once at boot rather than per read — the distinction that
+// makes the difference between a migration and the pathology this index exists
+// to avoid.
+func (c *Client) UDLBackfillUserCids() (int, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	if c.client == nil {
+		return 0, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
+	defer cancel()
+
+	pattern := c.buildKey("udl:idx:user:*:cid:*")
+	prefix := c.buildKey("udl:idx:user:")
+	added := 0
+	var cursor uint64
+	for {
+		keys, next, err := c.client.Scan(ctx, cursor, pattern, 500).Result()
+		if err != nil {
+			return added, fmt.Errorf("scan failed: %w", err)
+		}
+		for _, k := range keys {
+			// <prefix><uid>:cid:<cid> — split on the FIRST separator, not the
+			// last. A uid is multibase base58btc, whose alphabet contains no
+			// colon at all, so the first ":cid:" always ends the uid. A cid
+			// that happens to contain ":cid:" in its own name would make the
+			// last occurrence split in the wrong place.
+			rest := strings.TrimPrefix(k, prefix)
+			i := strings.Index(rest, ":cid:")
+			if i < 0 {
+				continue
+			}
+			uid, cid := rest[:i], rest[i+len(":cid:"):]
+			if uid == "" || cid == "" {
+				continue
+			}
+			n, err := c.client.SAdd(ctx, c.buildKey(udlIdxUserCids(uid)), cid).Result()
+			if err != nil {
+				return added, fmt.Errorf("sadd failed: %w", err)
+			}
+			added += int(n)
+		}
+		cursor = next
+		if cursor == 0 {
+			break
+		}
+	}
+	return added, nil
+}
+
 // UDLCidUsers returns every uid that has any record for cid — uids_for_cid.
 func (c *Client) UDLCidUsers(cid string) ([]string, error) {
 	c.mu.RLock()

internal/storage/udl_admin.go

@@ -0,0 +1,247 @@
+package storage
+
+// Account-scoped UDL administration: what a uid holds, and removing all of it.
+//
+// Both operations enumerate the same thing — every `udl:rec:<uid>/<cid>/<key>`
+// cell — because there is no per-user cid index to consult. The Redis model
+// (see udl.go) indexes user+key → cids and user+cid → keys, which answer
+// "what is in My List", not "everything this account ever wrote". Adding a
+// third index would put a write on every UDL upsert to serve two admin calls,
+// so these SCAN instead and accept being O(keyspace).
+//
+// That cost is why UDLAllUserStats exists as a bulk call rather than a per-uid
+// one: the accounts page needs a number for every account, and MATCH filters
+// server-side without indexing, so N per-uid calls would walk the keyspace N
+// times. One walk buckets them all.
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// UDLUserStats counts what one account holds. Records is the number of cells,
+// including tombstones — a retracted rating is still a row this account owns
+// and still something a purge has to remove.
+type UDLUserStats struct {
+	Records int `json:"records"`
+	Cids    int `json:"cids"`
+	Keys    int `json:"keys"`
+}
+
+// udlScanBatch is the SCAN COUNT hint, matching the rest of this package.
+const udlScanBatch = 1000
+
+// safeUIDForPattern rejects anything that would change the meaning of a SCAN
+// glob or reach across the key structure. meta-core's uids are alphanumeric
+// (identity.validUID), so this only ever fires on a hostile or malformed one —
+// but it fires here, in the layer that builds the pattern, rather than relying
+// on every caller having validated first.
+func safeUIDForPattern(uid string) error {
+	if uid == "" {
+		return fmt.Errorf("empty uid")
+	}
+	if strings.ContainsAny(uid, "*?[]\\/:") {
+		return fmt.Errorf("uid contains characters that are not valid in a uid: %q", uid)
+	}
+	return nil
+}
+
+// splitUDLRecSuffix splits the "<uid>/<cid>/<key>" tail of a udl:rec key.
+//
+// SplitN with a limit of 3 so a key containing a slash survives intact. cids
+// never contain one; keys are a controlled vocabulary today, but a namespaced
+// one arriving later must not silently truncate here — a truncated key would
+// make the purge SREM the wrong index member and leave the real one behind.
+func splitUDLRecSuffix(suffix string) (uid, cid, key string, ok bool) {
+	parts := strings.SplitN(suffix, "/", 3)
+	if len(parts) != 3 || parts[0] == "" || parts[1] == "" || parts[2] == "" {
+		return "", "", "", false
+	}
+	return parts[0], parts[1], parts[2], true
+}
+
+// scanKeys walks the keyspace for pattern and returns every match. Caller holds
+// the lock.
+//
+// SCAN can return the same key more than once across cursor iterations (it
+// guarantees no misses, not no duplicates), so callers that count must
+// de-duplicate — both callers below collect into maps or sets for that reason.
+func (c *Client) scanKeys(ctx context.Context, pattern string) ([]string, error) {
+	var (
+		out    []string
+		cursor uint64
+	)
+	for {
+		keys, next, err := c.client.Scan(ctx, cursor, pattern, udlScanBatch).Result()
+		if err != nil {
+			return nil, fmt.Errorf("scan %q: %w", pattern, err)
+		}
+		out = append(out, keys...)
+		cursor = next
+		if cursor == 0 {
+			return out, nil
+		}
+	}
+}
+
+// UDLUserCells returns every (cid, key) pair this account holds a cell for.
+// De-duplicated, since SCAN may repeat a key.
+func (c *Client) UDLUserCells(uid string) (map[string]string, error) {
+	// Keyed by the full "cid/key" tail so the pair stays a pair; the value is
+	// the cid, which the purge needs grouped.
+	if err := safeUIDForPattern(uid); err != nil {
+		return nil, err
+	}
+
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	if c.client == nil {
+		return nil, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	prefix := c.buildKey("udl:rec:")
+	keys, err := c.scanKeys(ctx, prefix+uid+"/*")
+	if err != nil {
+		return nil, err
+	}
+	out := make(map[string]string, len(keys))
+	for _, full := range keys {
+		gotUID, cid, key, ok := splitUDLRecSuffix(strings.TrimPrefix(full, prefix))
+		// The glob can only match this uid, but a uid that is a prefix of
+		// another would still be caught by the '/' in the pattern; check anyway
+		// so a malformed key can never be attributed to the wrong account.
+		if !ok || gotUID != uid {
+			continue
+		}
+		out[cid+"/"+key] = cid
+	}
+	return out, nil
+}
+
+// UDLAllUserStats counts every account's cells in one keyspace walk.
+//
+// Returns only accounts that actually hold records; a uid absent from the map
+// holds none. Callers render a zero for those rather than treating it as an
+// error — an account created a minute ago legitimately has nothing.
+func (c *Client) UDLAllUserStats() (map[string]UDLUserStats, error) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	if c.client == nil {
+		return nil, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 120*time.Second)
+	defer cancel()
+
+	prefix := c.buildKey("udl:rec:")
+	keys, err := c.scanKeys(ctx, prefix+"*")
+	if err != nil {
+		return nil, err
+	}
+
+	// Sets rather than counters: SCAN may hand back the same key twice, which
+	// would otherwise inflate every number on the page.
+	type acc struct {
+		cells map[string]struct{}
+		cids  map[string]struct{}
+		keys  map[string]struct{}
+	}
+	byUID := make(map[string]*acc)
+	for _, full := range keys {
+		uid, cid, key, ok := splitUDLRecSuffix(strings.TrimPrefix(full, prefix))
+		if !ok {
+			continue
+		}
+		a := byUID[uid]
+		if a == nil {
+			a = &acc{
+				cells: make(map[string]struct{}),
+				cids:  make(map[string]struct{}),
+				keys:  make(map[string]struct{}),
+			}
+			byUID[uid] = a
+		}
+		a.cells[cid+"/"+key] = struct{}{}
+		a.cids[cid] = struct{}{}
+		a.keys[key] = struct{}{}
+	}
+
+	out := make(map[string]UDLUserStats, len(byUID))
+	for uid, a := range byUID {
+		out[uid] = UDLUserStats{Records: len(a.cells), Cids: len(a.cids), Keys: len(a.keys)}
+	}
+	return out, nil
+}
+
+// UDLPurgeUser removes every trace of one account from the User Data Layer:
+// its cells, its three user-scoped indexes, and its membership in the shared
+// cid-scoped indexes. Returns what was removed.
+//
+// The shared indexes are the part that is easy to miss and expensive to leave.
+// `udl:idx:cid:<cid>:key:<key>` and `udl:idx:cid:<cid>:users` are keyed by cid,
+// not by uid, so a purge that only deleted `udl:rec:<uid>/*` would leave this
+// uid listed as an opinion-holder on every title it ever touched. Aggregation
+// then HGETs a cell that no longer exists — UDLPublicValues skips it, so the
+// rating average stays right, but uids_for_cid keeps naming a deleted account
+// forever and every aggregate read pays for the lookup.
+//
+// Idempotent: purging an account with nothing stored is a no-op returning
+// zeroes, so a retry after a partial failure is safe.
+func (c *Client) UDLPurgeUser(uid string) (UDLUserStats, error) {
+	cells, err := c.UDLUserCells(uid)
+	if err != nil {
+		return UDLUserStats{}, err
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.client == nil {
+		return UDLUserStats{}, fmt.Errorf("not connected")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 120*time.Second)
+	defer cancel()
+
+	stats := UDLUserStats{Records: len(cells)}
+	distinctCids := make(map[string]struct{})
+	distinctKeys := make(map[string]struct{})
+
+	pipe := c.client.Pipeline()
+	for cidKey, cid := range cells {
+		key := strings.TrimPrefix(cidKey, cid+"/")
+		distinctCids[cid] = struct{}{}
+		distinctKeys[key] = struct{}{}
+		pipe.Del(ctx, c.buildKey(udlRecKey(uid, cid, key)))
+		pipe.SRem(ctx, c.buildKey(udlIdxCidKey(cid, key)), uid)
+	}
+	for cid := range distinctCids {
+		pipe.SRem(ctx, c.buildKey(udlIdxCidUsers(cid)), uid)
+	}
+	stats.Cids = len(distinctCids)
+	stats.Keys = len(distinctKeys)
+
+	// The three user-scoped indexes (`:key:*`, `:cid:*`, `:cids`) are enumerable
+	// directly, and are dropped whole rather than member-by-member. The glob is
+	// what keeps this correct as indexes are added — `:cids` needed no change
+	// here when it landed. Scanning them separately also catches
+	// index entries whose cell is already gone — exactly the state a previously
+	// half-finished purge leaves behind.
+	idxPrefix := c.buildKey("udl:idx:user:") + uid + ":"
+	idxKeys, err := c.scanKeys(ctx, idxPrefix+"*")
+	if err != nil {
+		return UDLUserStats{}, err
+	}
+	for _, k := range idxKeys {
+		pipe.Del(ctx, k)
+	}
+
+	if _, err := pipe.Exec(ctx); err != nil {
+		return UDLUserStats{}, fmt.Errorf("purge pipeline: %w", err)
+	}
+	return stats, nil
+}

internal/storage/udl_admin_test.go

@@ -0,0 +1,253 @@
+package storage
+
+import (
+	"testing"
+)
+
+// seedCell writes one live UDL cell the way a real client would.
+func seedCell(t *testing.T, c *Client, uid, cid, key string) {
+	t.Helper()
+	if ok, err := c.UDLUpsertIfNewer(uid, cid, key, 1, 100, "rec", "", false, false); err != nil || !ok {
+		t.Fatalf("seed %s/%s/%s: ok=%v err=%v", uid, cid, key, ok, err)
+	}
+}
+
+// The purge has to reach the cid-scoped indexes, not just the user's own rows.
+//
+// This is the failure that motivated the whole endpoint: deleting an account
+// while leaving `udl:idx:cid:<cid>:users` intact means every aggregate read on
+// every title that account ever touched keeps naming a uid nobody can resolve,
+// forever — and the rows are unreachable through any API, so nothing will ever
+// clean them up.
+func TestUDLPurgeUser_RemovesCellsAndBothIndexFamilies(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedCell(t, c, "zAlice", "cidOne", "like")
+	seedCell(t, c, "zAlice", "cidOne", "rating")
+	seedCell(t, c, "zAlice", "cidTwo", "seek")
+
+	stats, err := c.UDLPurgeUser("zAlice")
+	if err != nil {
+		t.Fatalf("purge: %v", err)
+	}
+	if stats.Records != 3 || stats.Cids != 2 || stats.Keys != 3 {
+		t.Fatalf("stats = %+v, want 3 records / 2 cids / 3 keys", stats)
+	}
+
+	// Cells gone.
+	if _, ok, err := c.UDLGetCell("zAlice", "cidOne", "like"); err != nil || ok {
+		t.Fatalf("cell survived the purge: ok=%v err=%v", ok, err)
+	}
+	// User-scoped indexes gone.
+	if entries, err := c.UDLListUserKey("zAlice", "like"); err != nil || len(entries) != 0 {
+		t.Fatalf("user+key index survived: %d entries, err=%v", len(entries), err)
+	}
+	if entries, err := c.UDLListUserCid("zAlice", "cidOne"); err != nil || len(entries) != 0 {
+		t.Fatalf("user+cid index survived: %d entries, err=%v", len(entries), err)
+	}
+	// Cid-scoped index gone — the one that is easy to miss.
+	for _, cid := range []string{"cidOne", "cidTwo"} {
+		uids, err := c.UDLCidUsers(cid)
+		if err != nil {
+			t.Fatalf("cid users %s: %v", cid, err)
+		}
+		for _, u := range uids {
+			if u == "zAlice" {
+				t.Fatalf("%s still lists the deleted account in uids_for_cid", cid)
+			}
+		}
+	}
+}
+
+// Purging one account must not touch another's rows, including on a cid they
+// both have an opinion about — where the two share an index set and a careless
+// DEL of the whole key would take the survivor's membership with it.
+func TestUDLPurgeUser_LeavesOtherAccountsIntact(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedCell(t, c, "zAlice", "shared", "rating")
+	seedCell(t, c, "zBob", "shared", "rating")
+
+	if _, err := c.UDLPurgeUser("zAlice"); err != nil {
+		t.Fatalf("purge: %v", err)
+	}
+
+	if _, ok, err := c.UDLGetCell("zBob", "shared", "rating"); err != nil || !ok {
+		t.Fatalf("bob's cell must survive alice's purge: ok=%v err=%v", ok, err)
+	}
+	uids, err := c.UDLCidUsers("shared")
+	if err != nil {
+		t.Fatalf("cid users: %v", err)
+	}
+	if len(uids) != 1 || uids[0] != "zBob" {
+		t.Fatalf("uids_for_cid = %v, want exactly [zBob]", uids)
+	}
+	entries, err := c.UDLListUserKey("zBob", "rating")
+	if err != nil || len(entries) != 1 {
+		t.Fatalf("bob's user+key index must survive: %d entries, err=%v", len(entries), err)
+	}
+}
+
+// A uid that is a prefix of another must not drag its neighbour's rows out.
+// The key layout separates them with '/' and ':', so this passes only as long
+// as the scan patterns keep those separators.
+func TestUDLPurgeUser_DoesNotMatchUIDsByPrefix(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedCell(t, c, "zAlice", "cidOne", "like")
+	seedCell(t, c, "zAliceExtra", "cidOne", "like")
+
+	stats, err := c.UDLPurgeUser("zAlice")
+	if err != nil {
+		t.Fatalf("purge: %v", err)
+	}
+	if stats.Records != 1 {
+		t.Fatalf("purged %d records, want exactly alice's 1", stats.Records)
+	}
+	if _, ok, err := c.UDLGetCell("zAliceExtra", "cidOne", "like"); err != nil || !ok {
+		t.Fatalf("zAliceExtra's cell must survive: ok=%v err=%v", ok, err)
+	}
+}
+
+// Tombstoned cells still belong to the account. They are absent from the
+// user+key index by design (see udl.go), so a purge that enumerated *that*
+// index instead of the cells would leave every retracted rating behind — the
+// rows most likely to have accumulated over an account's life.
+func TestUDLPurgeUser_RemovesTombstonedCellsToo(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedCell(t, c, "zAlice", "cidOne", "like")
+	if ok, err := c.UDLUpsertIfNewer("zAlice", "cidOne", "like", 2, 200, "rec-tomb", "", false, true); err != nil || !ok {
+		t.Fatalf("tombstone: ok=%v err=%v", ok, err)
+	}
+	// Precondition: the tombstone left the cell but dropped it from the index.
+	if entries, _ := c.UDLListUserKey("zAlice", "like"); len(entries) != 0 {
+		t.Fatalf("precondition: tombstone should be out of the user+key index")
+	}
+
+	stats, err := c.UDLPurgeUser("zAlice")
+	if err != nil {
+		t.Fatalf("purge: %v", err)
+	}
+	if stats.Records != 1 {
+		t.Fatalf("purged %d records, want the 1 tombstoned cell", stats.Records)
+	}
+	if _, ok, _ := c.UDLGetCell("zAlice", "cidOne", "like"); ok {
+		t.Fatal("tombstoned cell survived the purge")
+	}
+}
+
+// Retry-safe: the delete handler purges before removing the key, so a caller
+// that retries after a partial failure runs this a second time.
+func TestUDLPurgeUser_IsIdempotent(t *testing.T) {
+	c, _ := newTestClient(t, "")
+	seedCell(t, c, "zAlice", "cidOne", "like")
+
+	if _, err := c.UDLPurgeUser("zAlice"); err != nil {
+		t.Fatalf("first purge: %v", err)
+	}
+	stats, err := c.UDLPurgeUser("zAlice")
+	if err != nil {
+		t.Fatalf("second purge must be a no-op, got: %v", err)
+	}
+	if stats.Records != 0 || stats.Cids != 0 {
+		t.Fatalf("second purge = %+v, want zeroes", stats)
+	}
+}
+
+func TestUDLPurgeUser_RefusesGlobInjection(t *testing.T) {
+	c, _ := newTestClient(t, "")
+	seedCell(t, c, "zAlice", "cidOne", "like")
+
+	// "*" would otherwise match every account in the keyspace — a wildcard
+	// purge dressed up as a uid.
+	for _, uid := range []string{"*", "z*", "", "z:Alice", "z/Alice"} {
+		if _, err := c.UDLPurgeUser(uid); err == nil {
+			t.Errorf("uid %q must be refused before it reaches a SCAN pattern", uid)
+		}
+	}
+	if _, ok, _ := c.UDLGetCell("zAlice", "cidOne", "like"); !ok {
+		t.Fatal("a refused purge must not have deleted anything")
+	}
+}
+
+func TestUDLAllUserStats_CountsEachAccountSeparately(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedCell(t, c, "zAlice", "cidOne", "like")
+	seedCell(t, c, "zAlice", "cidOne", "rating")
+	seedCell(t, c, "zAlice", "cidTwo", "like")
+	seedCell(t, c, "zBob", "cidOne", "seek")
+
+	stats, err := c.UDLAllUserStats()
+	if err != nil {
+		t.Fatalf("stats: %v", err)
+	}
+	if got := stats["zAlice"]; got.Records != 3 || got.Cids != 2 || got.Keys != 2 {
+		t.Fatalf("alice = %+v, want 3 records / 2 cids / 2 keys", got)
+	}
+	if got := stats["zBob"]; got.Records != 1 || got.Cids != 1 || got.Keys != 1 {
+		t.Fatalf("bob = %+v, want 1/1/1", got)
+	}
+	// An account with nothing stored is simply absent — the caller renders 0.
+	if _, present := stats["zNobody"]; present {
+		t.Fatal("an account with no records must not appear in the map")
+	}
+}
+
+// The stats and the purge must agree: the number shown in the delete
+// confirmation is the number of rows the delete then removes.
+func TestUDLAllUserStats_AgreesWithWhatPurgeRemoves(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	seedCell(t, c, "zAlice", "cidOne", "like")
+	seedCell(t, c, "zAlice", "cidTwo", "rating")
+	seedCell(t, c, "zAlice", "cidTwo", "seek")
+
+	before, err := c.UDLAllUserStats()
+	if err != nil {
+		t.Fatalf("stats: %v", err)
+	}
+	purged, err := c.UDLPurgeUser("zAlice")
+	if err != nil {
+		t.Fatalf("purge: %v", err)
+	}
+	if before["zAlice"] != purged {
+		t.Fatalf("stats said %+v but purge removed %+v", before["zAlice"], purged)
+	}
+}
+
+// The key prefix (multi-tenant Redis) must not leak into the parsed uid, or
+// every account on a prefixed node would be reported under a mangled name and
+// the purge would find nothing.
+func TestUDLAdmin_RespectsKeyPrefix(t *testing.T) {
+	c, _ := newTestClient(t, "tenantA:")
+
+	seedCell(t, c, "zAlice", "cidOne", "like")
+
+	stats, err := c.UDLAllUserStats()
+	if err != nil {
+		t.Fatalf("stats: %v", err)
+	}
+	if got := stats["zAlice"]; got.Records != 1 {
+		t.Fatalf("stats under a prefix = %+v, want 1 record for zAlice", stats)
+	}
+	if s, err := c.UDLPurgeUser("zAlice"); err != nil || s.Records != 1 {
+		t.Fatalf("purge under a prefix: %+v err=%v", s, err)
+	}
+}
+
+func TestSplitUDLRecSuffix_KeepsSlashesInTheKey(t *testing.T) {
+	// A namespaced key arriving later must not be truncated: the purge SREMs
+	// `udl:idx:cid:<cid>:key:<key>`, so a half-read key removes the wrong
+	// member and leaves the real one behind.
+	uid, cid, key, ok := splitUDLRecSuffix("zAlice/cidOne/ns/sub:key")
+	if !ok || uid != "zAlice" || cid != "cidOne" || key != "ns/sub:key" {
+		t.Fatalf("got (%q,%q,%q,%v)", uid, cid, key, ok)
+	}
+	for _, bad := range []string{"", "zAlice", "zAlice/cidOne", "zAlice//key", "/cid/key"} {
+		if _, _, _, ok := splitUDLRecSuffix(bad); ok {
+			t.Errorf("%q should not parse", bad)
+		}
+	}
+}

internal/storage/udl_export_test.go

@@ -0,0 +1,234 @@
+package storage
+
+import (
+	"context"
+	"testing"
+)
+
+// The whole-profile export is what cross-instance recovery reads: a box that
+// has just imported a secret key knows the uid and nothing else — not which
+// cids the profile touched, not which keys. Every one of these tests is about
+// that one caller.
+
+func TestUDLAllForUser_ReturnsEveryCellAcrossCidsAndKeys(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	const uid = "zAlice"
+	writes := []struct{ cid, key, rec string }{
+		{"bagcsaaaaone", "like", "rec-one-like"},
+		{"bagcsaaaaone", "seek", "rec-one-seek"},
+		{"bagcsaaaatwo", "rating", "rec-two-rating"},
+		{"bagcsaaaatwo", "profile:name", "rec-two-name"},
+		{"bagcsaaathree", "watched", "rec-three-watched"},
+	}
+	for _, w := range writes {
+		if ok, err := c.UDLUpsertIfNewer(uid, w.cid, w.key, 1, 100, w.rec, "", false, false); err != nil || !ok {
+			t.Fatalf("upsert %s/%s: ok=%v err=%v", w.cid, w.key, ok, err)
+		}
+	}
+
+	entries, next, err := c.UDLAllForUser(uid, "", 0)
+	if err != nil {
+		t.Fatalf("export: %v", err)
+	}
+	if next != "" {
+		t.Fatalf("export of 5 rows should be complete, got nextCid=%q", next)
+	}
+	if len(entries) != len(writes) {
+		t.Fatalf("want %d rows, got %d: %+v", len(writes), len(entries), entries)
+	}
+	seen := map[string]string{}
+	for _, e := range entries {
+		seen[e.Cid+"/"+e.Key] = e.Record
+	}
+	for _, w := range writes {
+		if got := seen[w.cid+"/"+w.key]; got != w.rec {
+			t.Errorf("%s/%s: want record %q, got %q", w.cid, w.key, w.rec, got)
+		}
+	}
+}
+
+// The failure this guards is silent and total: a uid whose cids were never
+// indexed exports as empty, and recovery reports success having restored
+// nothing.
+func TestUDLAllForUser_IsEmptyForAnUnknownUid(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	if ok, err := c.UDLUpsertIfNewer("zAlice", "bagcsaaaaone", "like", 1, 100, "rec", "", false, false); err != nil || !ok {
+		t.Fatalf("upsert: ok=%v err=%v", ok, err)
+	}
+	entries, _, err := c.UDLAllForUser("zBob", "", 0)
+	if err != nil {
+		t.Fatalf("export: %v", err)
+	}
+	if len(entries) != 0 {
+		t.Fatalf("Bob owns nothing; got %+v", entries)
+	}
+}
+
+// ⚠ The tombstone rule, and the reason the cids index is never pruned.
+//
+// A tombstone must EXPORT. It is the only thing that can beat the older live
+// value the other box still holds at a lower version — drop it from the export
+// and an un-liked title comes back from the dead on every peer that already
+// saw the `like`. This is the one place the cids index deliberately diverges
+// from the user+key index, which does prune.
+func TestUDLAllForUser_ExportsTombstones(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	const (
+		uid = "zAlice"
+		cid = "bagcsaaaaone"
+		key = "like"
+	)
+	if ok, err := c.UDLUpsertIfNewer(uid, cid, key, 1, 100, "rec-liked", "", false, false); err != nil || !ok {
+		t.Fatalf("live upsert: ok=%v err=%v", ok, err)
+	}
+	if ok, err := c.UDLUpsertIfNewer(uid, cid, key, 2, 200, "rec-unliked", "", false, true); err != nil || !ok {
+		t.Fatalf("tombstone upsert: ok=%v err=%v", ok, err)
+	}
+
+	// The user+key index prunes it — that is what keeps My List short.
+	live, err := c.UDLListUserKey(uid, key)
+	if err != nil {
+		t.Fatalf("active_for_user_key: %v", err)
+	}
+	if len(live) != 0 {
+		t.Fatalf("tombstoned cid should leave the user+key index, got %+v", live)
+	}
+
+	// The export must still carry it, at the tombstone's version.
+	entries, _, err := c.UDLAllForUser(uid, "", 0)
+	if err != nil {
+		t.Fatalf("export: %v", err)
+	}
+	if len(entries) != 1 {
+		t.Fatalf("tombstone must export, got %+v", entries)
+	}
+	if entries[0].Record != "rec-unliked" || entries[0].Version != 2 {
+		t.Fatalf("export must carry the tombstone, not the superseded value: %+v", entries[0])
+	}
+}
+
+func TestUDLAllForUser_PagesOnACidBoundaryAndResumes(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	const uid = "zAlice"
+	cids := []string{"bagcsaaaaa1", "bagcsaaaaa2", "bagcsaaaaa3"}
+	for _, cid := range cids {
+		for _, key := range []string{"like", "seek"} {
+			if ok, err := c.UDLUpsertIfNewer(uid, cid, key, 1, 100, "rec-"+cid+"-"+key, "", false, false); err != nil || !ok {
+				t.Fatalf("upsert: ok=%v err=%v", ok, err)
+			}
+		}
+	}
+
+	// A cid's keys are never split across a page, so a limit of 1 still yields
+	// both of the first cid's rows.
+	page1, next1, err := c.UDLAllForUser(uid, "", 1)
+	if err != nil {
+		t.Fatalf("page 1: %v", err)
+	}
+	if len(page1) != 2 || page1[0].Cid != cids[0] {
+		t.Fatalf("page 1 should hold both rows of %s, got %+v", cids[0], page1)
+	}
+	if next1 != cids[0] {
+		t.Fatalf("cursor should name the last cid emitted, want %q got %q", cids[0], next1)
+	}
+
+	// Walking the cursor must visit every row exactly once.
+	all := append([]UDLUserAllEntry{}, page1...)
+	cursor := next1
+	for cursor != "" {
+		page, next, err := c.UDLAllForUser(uid, cursor, 1)
+		if err != nil {
+			t.Fatalf("page after %q: %v", cursor, err)
+		}
+		all = append(all, page...)
+		cursor = next
+	}
+	if len(all) != 6 {
+		t.Fatalf("want 6 rows across all pages, got %d: %+v", len(all), all)
+	}
+	seen := map[string]bool{}
+	for _, e := range all {
+		k := e.Cid + "/" + e.Key
+		if seen[k] {
+			t.Fatalf("%s emitted twice across pages", k)
+		}
+		seen[k] = true
+	}
+}
+
+// Data written before the cids index existed must still export, or every
+// profile that predates this feature silently recovers as empty.
+func TestUDLBackfillUserCids_MakesLegacyDataExportable(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	const (
+		uid = "zAlice"
+		cid = "bagcsaaaaone"
+		key = "like"
+	)
+	if ok, err := c.UDLUpsertIfNewer(uid, cid, key, 1, 100, "rec", "", false, false); err != nil || !ok {
+		t.Fatalf("upsert: ok=%v err=%v", ok, err)
+	}
+
+	// Simulate the pre-index state: the cell and the other indexes exist, the
+	// cids set does not.
+	ctx := context.Background()
+	if err := c.client.Del(ctx, c.buildKey(udlIdxUserCids(uid))).Err(); err != nil {
+		t.Fatalf("del cids index: %v", err)
+	}
+	if entries, _, err := c.UDLAllForUser(uid, "", 0); err != nil || len(entries) != 0 {
+		t.Fatalf("precondition: legacy data should export as empty, got %+v err=%v", entries, err)
+	}
+
+	added, err := c.UDLBackfillUserCids()
+	if err != nil {
+		t.Fatalf("backfill: %v", err)
+	}
+	if added != 1 {
+		t.Fatalf("want 1 cid backfilled, got %d", added)
+	}
+	entries, _, err := c.UDLAllForUser(uid, "", 0)
+	if err != nil {
+		t.Fatalf("export after backfill: %v", err)
+	}
+	if len(entries) != 1 || entries[0].Cid != cid || entries[0].Key != key {
+		t.Fatalf("backfilled data should export, got %+v", entries)
+	}
+
+	// Idempotent: a second run adds nothing.
+	if added, err := c.UDLBackfillUserCids(); err != nil || added != 0 {
+		t.Fatalf("second backfill should be a no-op, added=%d err=%v", added, err)
+	}
+}
+
+// The backfill splits `<uid>:cid:<cid>` on the FIRST separator, because a uid
+// is multibase base58btc and its alphabet has no colon. Splitting on the last
+// occurrence — the obvious-looking choice — mis-parses a cid that contains
+// ":cid:" in its own name into uid "zAlice:cid:weird", cid "name".
+func TestUDLBackfillUserCids_SplitsOnTheFirstSeparator(t *testing.T) {
+	c, _ := newTestClient(t, "")
+
+	const uid = "zAlice"
+	cid := "weird:cid:name"
+	if ok, err := c.UDLUpsertIfNewer(uid, cid, "like", 1, 100, "rec", "", false, false); err != nil || !ok {
+		t.Fatalf("upsert: ok=%v err=%v", ok, err)
+	}
+	ctx := context.Background()
+	if err := c.client.Del(ctx, c.buildKey(udlIdxUserCids(uid))).Err(); err != nil {
+		t.Fatalf("del cids index: %v", err)
+	}
+	if _, err := c.UDLBackfillUserCids(); err != nil {
+		t.Fatalf("backfill: %v", err)
+	}
+	entries, _, err := c.UDLAllForUser(uid, "", 0)
+	if err != nil {
+		t.Fatalf("export: %v", err)
+	}
+	if len(entries) != 1 || entries[0].Cid != cid {
+		t.Fatalf("want the cid parsed whole, got %+v", entries)
+	}
+}

internal/watcher/dispatcher.go

@@ -50,8 +50,18 @@ func (d *Dispatcher) dispatchToStream(event FileEvent) {
 	client := d.storageClient
 	d.mu.RUnlock()
 
+	if err := PublishEvent(client, event); err != nil {
+		log.Printf("[Dispatcher] Failed to publish to stream: %v", err)
+	}
+}
+
+// PublishEvent appends one file event to the file:events stream. Exported so a
+// caller with no Dispatcher (POST /api/files/register on a box whose watcher is
+// off) emits exactly the entry the watcher would — meta-share's ipfs_seed
+// consumes this stream to chunk, seed and provide new files.
+func PublishEvent(client *storage.Client, event FileEvent) error {
 	if client == nil || !client.IsConnected() {
-		return
+		return fmt.Errorf("storage client not connected")
 	}
 
 	// Build stream fields
@@ -79,9 +89,7 @@ func (d *Dispatcher) dispatchToStream(event FileEvent) {
 	// `EmitReset → ClearStream` path is still the only way the stream gets
 	// truncated to zero (signalled to consumers via the `reset` event).
 	_, err := client.XAdd(EventsStream, EventsStreamMaxLen, fields)
-	if err != nil {
+	return err
-		log.Printf("[Dispatcher] Failed to publish to stream: %v", err)
-	}
 }
 
 // EmitReset clears the stream and emits a reset event

internal/watcher/watcher.go

@@ -4,7 +4,6 @@ import (
 	"log"
 	"os"
 	"path/filepath"
-	"strconv"
 	"strings"
 	"sync"
 
@@ -54,42 +53,8 @@ func (w *Watcher) writeFileTuple(absPath string, size, mtimeNano int64, midhash
 		return
 	}
 
-	uuid, err := w.storage.GetByCID(midhash)
+	if _, _, err := w.storage.RegisterFileTuple(absPath, size, mtimeNano, midhash); err != nil {
-	if err != nil {
+		log.Printf("[Watcher] register %s: %v", absPath, err)
-		log.Printf("[Watcher] GetByCID(%s): %v", midhash, err)
-		return
-	}
-
-	if uuid == "" {
-		// New content. Mint sets filePath/sizeByte/mtimeNano; SetProperty
-		// then writes the midhash as a cids/<cid> key-set member — and the
-		// cid_resolution.go hook registers the reverse-index alias for us.
-		uuid, err = w.storage.Mint(absPath, size, mtimeNano)
-		if err != nil {
-			log.Printf("[Watcher] Mint(%s): %v", absPath, err)
-			return
-		}
-		if err := w.storage.SetProperty(uuid, storage.CIDsKeyPrefix+midhash, "true"); err != nil {
-			log.Printf("[Watcher] SetProperty cids/%s for %s: %v", midhash, uuid, err)
-		}
-		return
-	}
-
-	// Known content. If this is a new physical path for the same content,
-	// record it as a duplicate. Otherwise refresh size/mtime — same content,
-	// same path, but the file may have been rewritten with a fresh mtime.
-	existing, _ := w.storage.GetProperty(uuid, "filePath")
-	if existing != absPath {
-		if _, err := w.storage.AddDuplicatePath(uuid, absPath); err != nil {
-			log.Printf("[Watcher] AddDuplicatePath %s @ %s: %v", uuid, absPath, err)
-		}
-		return
-	}
-	if _, err := w.storage.MergeMetadataFlat(uuid, map[string]string{
-		"sizeByte":  strconv.FormatInt(size, 10),
-		"mtimeNano": strconv.FormatInt(mtimeNano, 10),
-	}); err != nil {
-		log.Printf("[Watcher] refresh tuple for %s: %v", uuid, err)
 	}
 }
 

test/config_test.go

@@ -77,15 +77,9 @@ func TestConfigPaths(t *testing.T) {
 		t.Errorf("Unexpected LockFilePath: %s", cfg.LockFilePath())
 	}
 
-	if cfg.InfoFilePath() != "/test/locks/kv-leader.info" {
-		t.Errorf("Unexpected InfoFilePath: %s", cfg.InfoFilePath())
-	}
 
 	if cfg.RedisDataDir() != "/test/db/redis" {
 		t.Errorf("Unexpected RedisDataDir: %s", cfg.RedisDataDir())
 	}
 
-	if cfg.ServicesDir() != "/test/services" {
-		t.Errorf("Unexpected ServicesDir: %s", cfg.ServicesDir())
-	}
 }

test/election_test.go

@@ -1,144 +0,0 @@
-package test
-
-import (
-	"encoding/json"
-	"os"
-	"path/filepath"
-	"testing"
-
-	"github.com/metazla/meta-core/internal/leader"
-)
-
-func TestLeaderLockInfoJSON(t *testing.T) {
-	info := &leader.LeaderLockInfo{
-		Host:      "test-host",
-		API:       "redis://10.0.0.1:6379",
-		HTTP:      "http://10.0.0.1:8180",
-		BaseURL:   "http://localhost:8180",
-		Timestamp: 1704067200000,
-		PID:       12345,
-	}
-
-	// Marshal to JSON
-	data, err := json.MarshalIndent(info, "", "  ")
-	if err != nil {
-		t.Fatalf("Failed to marshal: %v", err)
-	}
-
-	// Verify JSON structure matches TypeScript format
-	var parsed map[string]interface{}
-	if err := json.Unmarshal(data, &parsed); err != nil {
-		t.Fatalf("Failed to unmarshal: %v", err)
-	}
-
-	if parsed["host"] != "test-host" {
-		t.Errorf("Expected host 'test-host', got '%v'", parsed["host"])
-	}
-
-	if parsed["api"] != "redis://10.0.0.1:6379" {
-		t.Errorf("Expected api 'redis://10.0.0.1:6379', got '%v'", parsed["api"])
-	}
-
-	if parsed["http"] != "http://10.0.0.1:8180" {
-		t.Errorf("Expected http 'http://10.0.0.1:8180', got '%v'", parsed["http"])
-	}
-
-	if parsed["baseUrl"] != "http://localhost:8180" {
-		t.Errorf("Expected baseUrl 'http://localhost:8180', got '%v'", parsed["baseUrl"])
-	}
-
-	// Timestamp should be a number
-	if _, ok := parsed["timestamp"].(float64); !ok {
-		t.Errorf("Expected timestamp to be a number, got %T", parsed["timestamp"])
-	}
-
-	// PID should be a number
-	if _, ok := parsed["pid"].(float64); !ok {
-		t.Errorf("Expected pid to be a number, got %T", parsed["pid"])
-	}
-}
-
-func TestLeaderLockInfoJSONOmitEmpty(t *testing.T) {
-	info := &leader.LeaderLockInfo{
-		Host:      "test-host",
-		API:       "redis://10.0.0.1:6379",
-		HTTP:      "http://10.0.0.1:8180",
-		BaseURL:   "", // Empty - should be omitted
-		Timestamp: 1704067200000,
-		PID:       12345,
-	}
-
-	data, err := json.Marshal(info)
-	if err != nil {
-		t.Fatalf("Failed to marshal: %v", err)
-	}
-
-	// baseUrl should not be present when empty
-	var parsed map[string]interface{}
-	if err := json.Unmarshal(data, &parsed); err != nil {
-		t.Fatalf("Failed to unmarshal: %v", err)
-	}
-
-	if _, exists := parsed["baseUrl"]; exists {
-		t.Error("Expected baseUrl to be omitted when empty")
-	}
-}
-
-func TestLeaderInfoFileFormat(t *testing.T) {
-	// Create a temp directory
-	tmpDir, err := os.MkdirTemp("", "meta-core-test")
-	if err != nil {
-		t.Fatalf("Failed to create temp dir: %v", err)
-	}
-	defer os.RemoveAll(tmpDir)
-
-	info := &leader.LeaderLockInfo{
-		Host:      "test-host",
-		API:       "redis://10.0.0.1:6379",
-		HTTP:      "http://10.0.0.1:8180",
-		Timestamp: 1704067200000,
-		PID:       12345,
-	}
-
-	// Write to file
-	infoPath := filepath.Join(tmpDir, "kv-leader.info")
-	data, err := json.MarshalIndent(info, "", "  ")
-	if err != nil {
-		t.Fatalf("Failed to marshal: %v", err)
-	}
-
-	if err := os.WriteFile(infoPath, data, 0644); err != nil {
-		t.Fatalf("Failed to write file: %v", err)
-	}
-
-	// Read and parse
-	readData, err := os.ReadFile(infoPath)
-	if err != nil {
-		t.Fatalf("Failed to read file: %v", err)
-	}
-
-	var parsed leader.LeaderLockInfo
-	if err := json.Unmarshal(readData, &parsed); err != nil {
-		t.Fatalf("Failed to unmarshal: %v", err)
-	}
-
-	if parsed.Host != info.Host {
-		t.Errorf("Host mismatch: expected '%s', got '%s'", info.Host, parsed.Host)
-	}
-
-	if parsed.API != info.API {
-		t.Errorf("API mismatch: expected '%s', got '%s'", info.API, parsed.API)
-	}
-
-	if parsed.HTTP != info.HTTP {
-		t.Errorf("HTTP mismatch: expected '%s', got '%s'", info.HTTP, parsed.HTTP)
-	}
-
-	if parsed.Timestamp != info.Timestamp {
-		t.Errorf("Timestamp mismatch: expected %d, got %d", info.Timestamp, parsed.Timestamp)
-	}
-
-	if parsed.PID != info.PID {
-		t.Errorf("PID mismatch: expected %d, got %d", info.PID, parsed.PID)
-	}
-}