diff --git a/README.md b/README.md
index f426c7b..a495da2 100644
--- a/README.md
+++ b/README.md
@@ -209,6 +209,7 @@ 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
diff --git a/docs/meta-core-architecture.md b/docs/meta-core-architecture.md
index 7a8bd7d..b57dbac 100644
--- a/docs/meta-core-architecture.md
+++ b/docs/meta-core-architecture.md
@@ -301,6 +301,7 @@ 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
diff --git a/internal/api/files_tuples.go b/internal/api/files_tuples.go
new file mode 100644
index 0000000..d2a5b35
--- /dev/null
+++ b/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)
+}
diff --git a/internal/api/files_tuples_test.go b/internal/api/files_tuples_test.go
new file mode 100644
index 0000000..d38c91d
--- /dev/null
+++ b/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)
+	}
+}
diff --git a/internal/api/server.go b/internal/api/server.go
index 6b0c75a..a1e3b17 100644
--- a/internal/api/server.go
+++ b/internal/api/server.go
@@ -247,6 +247,10 @@ func (s *Server) setupRoutes() {
 	// 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