diff --git a/ts/EFFECT_NATIVE_REWRITE_AUDIT.md b/ts/EFFECT_NATIVE_REWRITE_AUDIT.md
index 305d94a6..33d43c58 100644
--- a/ts/EFFECT_NATIVE_REWRITE_AUDIT.md
+++ b/ts/EFFECT_NATIVE_REWRITE_AUDIT.md
@@ -12,19 +12,19 @@ Verified source roots:
 - Effect v4 subtree: `/home/elpresidank/YeeBois/projects/beep-effect2/.repos/effect-v4`
 - Installed Effect beta used by this workspace: `ts/node_modules/effect`
 
-Current signal counts from `ts/packages` after the 2026-06-02 Librarian tagged
-operation helper slice:
+Current signal counts from `ts/packages` after the 2026-06-02 Librarian typed
+runtime loop slice:
 
 | Signal | Count |
 | --- | ---: |
-| `Effect.runPromise` | 209 |
-| `Map<` | 74 |
+| `Effect.runPromise` | 208 |
+| `Map<` | 77 |
 | `WebSocket` | 47 |
 | `new Map` | 56 |
 | `toPromiseRequestor` | 0 |
 | `makeAsyncProcessor` | 19 |
 | `receive(` | 18 |
-| `while (` | 10 |
+| `while (` | 9 |
 | `new Error` | 14 |
 | `new Promise` | 10 |
 | `JSON.parse` | 7 |
@@ -46,8 +46,8 @@ Notes:
   snapshot because the FlowManager slice added focused service tests and
   Promise compatibility facades while removing the service's internal mutable
   object state.
-- The remaining `Record<string, any>` hit is the librarian service object and
-  should be removed in the next librarian state migration slice.
+- `Record<string, any>` and `throwLibrarianServiceError` are now clean in
+  `ts/packages`.
 
 ## Loop Passes
 
@@ -294,9 +294,9 @@ Notes:
   - The librarian tests now await the Promise compatibility facade for upload
     status.
 - Remaining:
-  - Librarian still has the dynamic service object, mutable maps/handles on
-    that object, and a raw `while (service.running)` poll loop. That remains
-    the next P0 state/ref-backed migration.
+  - The typed runtime loop slice addresses the dynamic service object and raw
+    poll loop. Librarian mutable maps/handles remain the next P0 ref-backed
+    state migration.
 - Verification:
   - `bun run --cwd ts/packages/flow test -- src/__tests__/librarian-service.test.ts`
   - `bun run --cwd ts/packages/flow build`
@@ -306,6 +306,31 @@ Notes:
   - `cd ts && bun run test`
   - `git diff --check`
 
+### 2026-06-02: Librarian Typed Runtime Loop Slice
+
+- Status: migrated and root-verified.
+- Completed:
+  - `ts/packages/flow/src/librarian/service.ts` now exposes a typed
+    `LibrarianService` interface instead of `AsyncProcessorRuntime &
+    Record<string, any>`.
+  - Service construction now uses `makeAsyncProcessor<LibrarianServiceError>`
+    with `runEffect`; the old method-bag `run` override and
+    `as LibrarianService` cast are gone.
+  - The librarian startup poller now uses `Effect.whileLoop`.
+  - The local operation helpers retrieve the initialized service through an
+    Effect gate rather than closing over an unsafe partially built value.
+- Remaining:
+  - Librarian still stores `documents`, `processing`, `uploads`, collection
+    manager, and producer/consumer handles as mutable fields. Move those into
+    `SynchronizedRef<LibrarianServiceState>` next.
+- Verification:
+  - `bun run --cwd ts/packages/flow build`
+  - `cd ts && bun run check`
+  - `bun run --cwd ts/packages/flow test`
+  - `cd ts && bun run build`
+  - `cd ts && bun run test`
+  - `git diff --check`
+
 ## Subagent Findings To Preserve
 
 - MCP/workbench:
@@ -316,10 +341,10 @@ Notes:
   - MCP env is now Config-backed; continue that policy for future MCP settings.
 - Flow stateful services:
   - Config service, KnowledgeCore service, and FlowManager ref-backed state
-    are complete. Librarian now has native Effect module startup
-    (`NodeRuntime.runMain` with a `ManagedRuntime` compatibility facade), but
-    it still has a mutable poller service object. It remains a good candidate
-    for `Context` services, scoped layers, `Ref`/`SynchronizedRef`,
+    are complete. Librarian now has native Effect module startup, a typed
+    service surface, and an `Effect.whileLoop` runtime, but it still stores
+    service maps and pubsub handles as mutable fields. It remains a good
+    candidate for `Context` services, scoped layers, `Ref`/`SynchronizedRef`,
     `Schedule`, and managed persistence.
   - Persistence IO should move toward `FileSystem` or `KeyValueStore` where
     the installed beta has the needed provider surface.
@@ -346,7 +371,7 @@ Notes:
 
 ## Ranked Findings
 
-### P0: Migrate Librarian Stateful Service To Scoped Effect Service
+### P0: Migrate Librarian Mutable State To Ref-Backed Effect Service
 
 - TrustGraph evidence:
   - `ts/packages/flow/src/librarian/service.ts`
diff --git a/ts/packages/flow/src/librarian/service.ts b/ts/packages/flow/src/librarian/service.ts
index 264c9129..dde1c875 100644
--- a/ts/packages/flow/src/librarian/service.ts
+++ b/ts/packages/flow/src/librarian/service.ts
@@ -16,6 +16,8 @@ import {
   makeProcessorProgram,
   type ProcessorConfig,
   type AsyncProcessorRuntime,
+  type BackendConsumer,
+  type BackendProducer,
   topics,
   type LibrarianRequest,
   type LibrarianResponse,
@@ -29,9 +31,9 @@ import {
 } from "@trustgraph/base";
 import type { Message } from "@trustgraph/base";
 import { NodeRuntime } from "@effect/platform-node";
-import { Clock, Config, Context, DateTime, Duration, Effect, Layer, ManagedRuntime, Option, Random } from "effect";
+import { Clock, Config, DateTime, Duration, Effect, Layer, ManagedRuntime, Option, Random } from "effect";
 import * as S from "effect/Schema";
-import { makeCollectionManager } from "./collection-manager.js";
+import { makeCollectionManager, type CollectionManager } from "./collection-manager.js";
 import {
   ensureDirectory,
   joinPath,
@@ -141,64 +143,218 @@ const randomUuid: Effect.Effect<string> = Effect.gen(function* () {
   ].join("-");
 });
 
-export type LibrarianService = AsyncProcessorRuntime & Record<string, any>;
+export interface LibrarianService extends AsyncProcessorRuntime<LibrarianServiceError> {
+  documents: Map<string, DocumentMetadata>;
+  processing: Map<string, ProcessingMetadata>;
+  uploads: Map<string, UploadSession>;
+  collectionManager: CollectionManager;
+  libConsumer: BackendConsumer<LibrarianRequest> | null;
+  libProducer: BackendProducer<LibrarianResponse> | null;
+  colConsumer: BackendConsumer<CollectionManagementRequest> | null;
+  colProducer: BackendProducer<CollectionManagementResponse> | null;
+  dataDir: string;
+  persistPath: string;
+  requestRecord: (request: LibrarianRequest) => Record<string, unknown>;
+  documentId: (request: LibrarianRequest) => string | undefined;
+  processingId: (request: LibrarianRequest) => string | undefined;
+  documentMetadata: (request: LibrarianRequest) => Promise<DocumentMetadata | undefined>;
+  processingMetadata: (request: LibrarianRequest) => Promise<ProcessingMetadata | undefined>;
+  normaliseDocumentMetadata: (value: Record<string, unknown>) => Promise<DocumentMetadata>;
+  publicDocument: (doc: DocumentMetadata) => DocumentMetadata;
+  publicProcessing: (proc: ProcessingMetadata) => ProcessingMetadata;
+  documentResponse: (doc: DocumentMetadata) => LibrarianResponse;
+  documentsResponse: (docs: DocumentMetadata[]) => LibrarianResponse;
+  processingResponse: (records: ProcessingMetadata[]) => LibrarianResponse;
+  handleLibrarianMessage: (msg: Message<LibrarianRequest>) => Promise<void>;
+  handleLibrarianOperation: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  addDocument: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  removeDocument: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  updateDocument: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  listDocuments: (request: LibrarianRequest) => LibrarianResponse;
+  getDocumentMetadata: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  getDocumentContent: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  addChildDocument: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  listChildren: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  addProcessing: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  removeProcessing: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  listProcessing: (request: LibrarianRequest) => LibrarianResponse;
+  beginUpload: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  uploadChunk: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  completeUpload: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  getUploadStatus: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  abortUpload: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  listUploads: (request: LibrarianRequest) => Promise<LibrarianResponse>;
+  streamDocument: (request: LibrarianRequest) => Promise<LibrarianResponse[]>;
+  handleCollectionMessage: (msg: Message<CollectionManagementRequest>) => Promise<void>;
+  handleCollectionOperation: (request: CollectionManagementRequest) => Promise<CollectionManagementResponse>;
+  persist: () => Promise<void>;
+  loadFromDisk: () => Promise<void>;
+}
+
+const consumeOnceEffect = (
+  service: LibrarianService,
+): Effect.Effect<void, LibrarianServiceError> =>
+  Effect.gen(function* () {
+    const libConsumer = service.libConsumer;
+    if (libConsumer === null) {
+      return yield* librarianServiceError("consume", "Librarian consumer not started");
+    }
+    const colConsumer = service.colConsumer;
+    if (colConsumer === null) {
+      return yield* librarianServiceError("consume", "Collection consumer not started");
+    }
+
+    const libMsg = yield* Effect.tryPromise({
+      try: () => libConsumer.receive(2000),
+      catch: (cause) => librarianServiceError("librarian-receive", cause),
+    });
+    if (libMsg !== null) {
+      yield* Effect.tryPromise({
+        try: () => service.handleLibrarianMessage(libMsg),
+        catch: (cause) => librarianServiceError("librarian-handle", cause),
+      });
+      yield* Effect.tryPromise({
+        try: () => libConsumer.acknowledge(libMsg),
+        catch: (cause) => librarianServiceError("librarian-acknowledge", cause),
+      });
+    }
+
+    const colMsg = yield* Effect.tryPromise({
+      try: () => colConsumer.receive(2000),
+      catch: (cause) => librarianServiceError("collection-receive", cause),
+    });
+    if (colMsg !== null) {
+      yield* Effect.tryPromise({
+        try: () => service.handleCollectionMessage(colMsg),
+        catch: (cause) => librarianServiceError("collection-handle", cause),
+      });
+      yield* Effect.tryPromise({
+        try: () => colConsumer.acknowledge(colMsg),
+        catch: (cause) => librarianServiceError("collection-acknowledge", cause),
+      });
+    }
+  });
+
+const runLibrarianServiceEffect = (
+  service: LibrarianService,
+): Effect.Effect<void, LibrarianServiceError> =>
+  Effect.gen(function* () {
+    yield* Effect.tryPromise({
+      try: () => ensureDirectory(joinPath(service.dataDir, "docs")),
+      catch: (cause) => librarianServiceError("ensure-data-dir", cause),
+    });
+
+    yield* Effect.tryPromise({
+      try: () => service.loadFromDisk(),
+      catch: (cause) => librarianServiceError("load", cause),
+    });
+
+    service.libProducer = yield* Effect.tryPromise({
+      try: () => service.pubsub.createProducer<LibrarianResponse>({
+        topic: topics.librarianResponse,
+      }),
+      catch: (cause) => librarianServiceError("librarian-producer", cause),
+    });
+    service.colProducer = yield* Effect.tryPromise({
+      try: () => service.pubsub.createProducer<CollectionManagementResponse>({
+        topic: topics.collectionManagementResponse,
+      }),
+      catch: (cause) => librarianServiceError("collection-producer", cause),
+    });
+
+    service.libConsumer = yield* Effect.tryPromise({
+      try: () => service.pubsub.createConsumer<LibrarianRequest>({
+        topic: topics.librarianRequest,
+        subscription: `${service.config.id}-librarian-request`,
+      }),
+      catch: (cause) => librarianServiceError("librarian-consumer", cause),
+    });
+    service.colConsumer = yield* Effect.tryPromise({
+      try: () => service.pubsub.createConsumer<CollectionManagementRequest>({
+        topic: topics.collectionManagementRequest,
+        subscription: `${service.config.id}-collection-management-request`,
+      }),
+      catch: (cause) => librarianServiceError("collection-consumer", cause),
+    });
+
+    yield* Effect.log(`[LibrarianService] Listening on ${topics.librarianRequest} and ${topics.collectionManagementRequest}`);
+
+    yield* Effect.whileLoop({
+      while: () => service.running,
+      body: () =>
+        consumeOnceEffect(service).pipe(
+          Effect.catch((err) => {
+            if (!service.running) return Effect.void;
+            return Effect.logError("[LibrarianService] Error in consume loop", { error: err.message }).pipe(
+              Effect.flatMap(() => Effect.sleep(Duration.millis(1000))),
+            );
+          }),
+        ),
+      step: () => undefined,
+    });
+  });
 
 export function makeLibrarianService(config: LibrarianServiceConfig): LibrarianService {
-  const service = makeAsyncProcessor(config, {
-    run: () => service.run(Context.empty()),
-  }) as LibrarianService;
-  const baseStop = service.stop;
-  service.documents = new Map<string, DocumentMetadata>();
-  service.processing = new Map<string, ProcessingMetadata>();
-  service.uploads = new Map<string, UploadSession>();
-  service.collectionManager = makeCollectionManager();
-  service.libConsumer = null;
-  service.libProducer = null;
-  service.colConsumer = null;
-  service.colProducer = null;
-  service.dataDir = resolveDataDir(config);
-  service.persistPath = joinPath(service.dataDir, "librarian-state.json");
+  let service: LibrarianService | undefined;
+
+  const getService = Effect.sync(() => service).pipe(
+    Effect.flatMap((current) =>
+      current === undefined
+        ? Effect.fail(librarianServiceError("service", "Librarian service not initialized"))
+        : Effect.succeed(current)
+    ),
+  );
+
+  const base = makeAsyncProcessor<LibrarianServiceError>(config, {
+    runEffect: () => getService.pipe(Effect.flatMap(runLibrarianServiceEffect)),
+  });
+  const baseStop = base.stop;
+  const dataDir = resolveDataDir(config);
+  const persistPath = joinPath(dataDir, "librarian-state.json");
 
   const getDocumentMetadataEffect = (request: LibrarianRequest): Effect.Effect<LibrarianResponse, LibrarianServiceError> =>
     Effect.gen(function* () {
-      const id = service.documentId(request);
+      const current = yield* getService;
+      const id = current.documentId(request);
       if (id === undefined || id.length === 0) {
         return yield* librarianServiceError("get-document-metadata", "get-document-metadata requires documentId");
       }
 
-      const doc = service.documents.get(id);
+      const doc = current.documents.get(id);
       if (doc === undefined) {
         return yield* librarianServiceError("get-document-metadata", `Document not found: ${id}`);
       }
 
-      return service.documentResponse(doc);
+      return current.documentResponse(doc);
     });
 
   const listChildrenEffect = (request: LibrarianRequest): Effect.Effect<LibrarianResponse, LibrarianServiceError> =>
     Effect.gen(function* () {
-      const parentId = service.documentId(request);
+      const current = yield* getService;
+      const parentId = current.documentId(request);
       if (parentId === undefined || parentId.length === 0) {
         return yield* librarianServiceError("list-children", "list-children requires documentId");
       }
 
       const children: DocumentMetadata[] = [];
-      for (const doc of service.documents.values()) {
+      for (const doc of current.documents.values()) {
         if (doc.parentId === parentId) {
           children.push(doc);
         }
       }
 
-      return service.documentsResponse(children);
+      return current.documentsResponse(children);
     });
 
   const uploadChunkEffect = (request: LibrarianRequest): Effect.Effect<LibrarianResponse, LibrarianServiceError> =>
     Effect.gen(function* () {
-      const req = service.requestRecord(request);
+      const current = yield* getService;
+      const req = current.requestRecord(request);
       const uploadId = optionalString(req["upload-id"]);
       if (uploadId === undefined) {
         return yield* librarianServiceError("upload-chunk", "upload-chunk requires upload-id");
       }
-      const session = service.uploads.get(uploadId);
+      const session = current.uploads.get(uploadId);
       if (session === undefined) {
         return yield* librarianServiceError("upload-chunk", `Upload not found: ${uploadId}`);
       }
@@ -225,11 +381,12 @@ export function makeLibrarianService(config: LibrarianServiceConfig): LibrarianS
 
   const getUploadStatusEffect = (request: LibrarianRequest): Effect.Effect<LibrarianResponse, LibrarianServiceError> =>
     Effect.gen(function* () {
-      const uploadId = optionalString(service.requestRecord(request)["upload-id"]);
+      const current = yield* getService;
+      const uploadId = optionalString(current.requestRecord(request)["upload-id"]);
       if (uploadId === undefined) {
         return yield* librarianServiceError("get-upload-status", "get-upload-status requires upload-id");
       }
-      const session = service.uploads.get(uploadId);
+      const session = current.uploads.get(uploadId);
       if (session === undefined) {
         return yield* librarianServiceError("get-upload-status", `Upload not found: ${uploadId}`);
       }
@@ -251,125 +408,26 @@ export function makeLibrarianService(config: LibrarianServiceConfig): LibrarianS
 
   const abortUploadEffect = (request: LibrarianRequest): Effect.Effect<LibrarianResponse, LibrarianServiceError> =>
     Effect.gen(function* () {
-      const uploadId = optionalString(service.requestRecord(request)["upload-id"]);
+      const current = yield* getService;
+      const uploadId = optionalString(current.requestRecord(request)["upload-id"]);
       if (uploadId === undefined) {
         return yield* librarianServiceError("abort-upload", "abort-upload requires upload-id");
       }
-      service.uploads.delete(uploadId);
+      current.uploads.delete(uploadId);
       return {};
     });
 
-  Object.assign(service, {
-
-
-      run: function(this: LibrarianService): Promise<void> {
-        const service = this;
-        return Effect.runPromise(
-          Effect.gen(function* () {
-            // Ensure directories exist
-            yield* Effect.tryPromise({
-              try: () => ensureDirectory(joinPath(service.dataDir, "docs")),
-              catch: (cause) => librarianServiceError("ensure-data-dir", cause),
-            });
-
-            // Load persisted state
-            yield* Effect.tryPromise({
-              try: () => service.loadFromDisk(),
-              catch: (cause) => librarianServiceError("load", cause),
-            });
-
-            // Create producers
-            service.libProducer = yield* Effect.tryPromise({
-              try: () => service.pubsub.createProducer<LibrarianResponse>({
-                topic: topics.librarianResponse,
-              }),
-              catch: (cause) => librarianServiceError("librarian-producer", cause),
-            });
-            service.colProducer = yield* Effect.tryPromise({
-              try: () => service.pubsub.createProducer<CollectionManagementResponse>({
-                topic: topics.collectionManagementResponse,
-              }),
-              catch: (cause) => librarianServiceError("collection-producer", cause),
-            });
-
-            // Create consumers
-            service.libConsumer = yield* Effect.tryPromise({
-              try: () => service.pubsub.createConsumer<LibrarianRequest>({
-                topic: topics.librarianRequest,
-                subscription: `${service.config.id}-librarian-request`,
-              }),
-              catch: (cause) => librarianServiceError("librarian-consumer", cause),
-            });
-            service.colConsumer = yield* Effect.tryPromise({
-              try: () => service.pubsub.createConsumer<CollectionManagementRequest>({
-                topic: topics.collectionManagementRequest,
-                subscription: `${service.config.id}-collection-management-request`,
-              }),
-              catch: (cause) => librarianServiceError("collection-consumer", cause),
-            });
-
-            yield* Effect.log(`[LibrarianService] Listening on ${topics.librarianRequest} and ${topics.collectionManagementRequest}`);
-
-            // Main consume loop -- poll both consumers
-            while (service.running) {
-              const shouldContinue = yield* Effect.gen(function* () {
-                const libConsumer = service.libConsumer;
-                if (libConsumer === null) {
-                  return yield* librarianServiceError("consume", "Librarian consumer not started");
-                }
-                const colConsumer = service.colConsumer;
-                if (colConsumer === null) {
-                  return yield* librarianServiceError("consume", "Collection consumer not started");
-                }
-
-                const libMsg = yield* Effect.tryPromise({
-                  try: () => libConsumer.receive(2000),
-                  catch: (cause) => librarianServiceError("librarian-receive", cause),
-                });
-                if (libMsg !== null) {
-                  yield* Effect.tryPromise({
-                    try: () => service.handleLibrarianMessage(libMsg),
-                    catch: (cause) => librarianServiceError("librarian-handle", cause),
-                  });
-                  yield* Effect.tryPromise({
-                    try: () => libConsumer.acknowledge(libMsg),
-                    catch: (cause) => librarianServiceError("librarian-acknowledge", cause),
-                  });
-                }
-
-                const colMsg = yield* Effect.tryPromise({
-                  try: () => colConsumer.receive(2000),
-                  catch: (cause) => librarianServiceError("collection-receive", cause),
-                });
-                if (colMsg !== null) {
-                  yield* Effect.tryPromise({
-                    try: () => service.handleCollectionMessage(colMsg),
-                    catch: (cause) => librarianServiceError("collection-handle", cause),
-                  });
-                  yield* Effect.tryPromise({
-                    try: () => colConsumer.acknowledge(colMsg),
-                    catch: (cause) => librarianServiceError("collection-acknowledge", cause),
-                  });
-                }
-
-                return true;
-              }).pipe(
-                Effect.catch((err) => {
-                  if (!service.running) return Effect.succeed(false);
-                  return Effect.logError("[LibrarianService] Error in consume loop", { error: err.message }).pipe(
-                    Effect.flatMap(() => Effect.sleep(Duration.millis(1000))),
-                    Effect.as(true),
-                  );
-                }),
-              );
-              if (!shouldContinue) break;
-            }
-          }),
-        );
-
-        },
-
-
+  const librarianService: LibrarianService = Object.assign(base, {
+      documents: new Map<string, DocumentMetadata>(),
+      processing: new Map<string, ProcessingMetadata>(),
+      uploads: new Map<string, UploadSession>(),
+      collectionManager: makeCollectionManager(),
+      libConsumer: null,
+      libProducer: null,
+      colConsumer: null,
+      colProducer: null,
+      dataDir,
+      persistPath,
 
       // ---------- Librarian message handling ----------
 
@@ -1373,7 +1431,8 @@ export function makeLibrarianService(config: LibrarianServiceConfig): LibrarianS
 
         }
   });
-  return service;
+  service = librarianService;
+  return librarianService;
 }
 
 export const LibrarianService = makeLibrarianService;