@@ -0,0 +1,152 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#25467 cut 25] The post-persistence mutation fan-out of
+ * `ObjectStackProtocolImplementation`, moved out of `protocol.ts` whole: the
+ * four members that tell the rest of the process — and, through the cluster
+ * transport, the rest of the fleet — that a metadata write has landed.
+ *
+ *  - `runMutationProjector` — the registered projector for a just-persisted
+ *    mutation (ADR-0094), awaited, never throwing.
+ *  - `notifyMutationListenersLocal` — the LOCAL half of
+ *    `emitMetadataMutation` (#2588, #13331): each listener isolated.
+ *  - `publishMetadataMutation` — the cluster half of `emitMetadataMutation`
+ *    (#13331): the mutation's address to peers, fire-and-forget, drafts
+ *    skipped.
+ *  - `emitMetaItemPublished` — the per-item publish listeners (#10219),
+ *    awaited and isolated.
+ *
+ * A MOVE, not a redesign. Each function below is the body of the
+ * `ObjectStackProtocolImplementation` method of the same name as it stood,
+ * re-indented one level and otherwise unedited: the same order, the same
+ * isolation, the same log lines.
+ *
+ * ## How the moved bodies reach the class
+ *
+ * The shape #23050 set for `rest-server.ts` (its `data-action-routes.ts`
+ * header carries the full reasoning), as `protocol-batch-data.ts` applies it.
+ * The class keeps each method — the published `dist/*.d.ts` lists its name,
+ * docblock and declared signature — and its body is one literal of exactly
+ * the {@link MutationFanOutHost} members it reads, plus a `.call`. Every
+ * member read is a field, so each is handed over as a getter: the body reads
+ * the protocol's own listener arrays, projector map and cluster wiring at
+ * call time — `attachMetadataMutationPubSub` and
+ * `detachMetadataMutationPubSub` reassign `clusterPubSub` and
+ * `clusterNodeId`, and the getters see the current values, as the bodies did.
+ *
+ * The callers stay in the class and keep calling the class methods:
+ * `emitMetadataMutation` (local, then cluster), `applyRemoteMetadataMutation`
+ * (local only), the seven projecting doors and the per-item publish door. So
+ * the call-site counts that `protocol.recovery-doors-emit-mutation.test.ts`
+ * and `protocol.recovery-doors-mutation-projector.test.ts` take over
+ * `protocol.ts` do not move.
+ *
+ * What the bodies read from elsewhere, they import from where `protocol.ts`
+ * declares it. Nothing re-exports this module, so the published surface does
+ * not move.
+ */
+
+import type {
+    ClusterMetadataMutationPayload,
+    MetadataMutationEvent,
+    MetaItemPublishedEvent,
+    MutationProjectionOutcome,
+    ObjectStackProtocolImplementation,
+} from './protocol.js';
+import { METADATA_MUTATION_CLUSTER_CHANNEL } from './protocol.js';
+
+/**
+ * The `ObjectStackProtocolImplementation` members the functions below read —
+ * every one of them, and no other; each function's `this` is the `Pick` of
+ * the members it reads. Each is typed AS the class member (an indexed access
+ * on the class), so a change to a member's type on the class is a change
+ * here too, and naming a member the class does not have is a compile error.
+ */
+export interface MutationFanOutHost {
+    readonly mutationProjectors: ObjectStackProtocolImplementation['mutationProjectors'];
+    readonly metadataMutationListeners: ObjectStackProtocolImplementation['metadataMutationListeners'];
+    readonly clusterPubSub: ObjectStackProtocolImplementation['clusterPubSub'];
+    readonly clusterNodeId: ObjectStackProtocolImplementation['clusterNodeId'];
+    readonly metaItemPublishedListeners: ObjectStackProtocolImplementation['metaItemPublishedListeners'];
+}
+
+/** The body of `ObjectStackProtocolImplementation#runMutationProjector`; the method's docblock there is its contract. */
+export async function runMutationProjector(
+    this: Pick<MutationFanOutHost, 'mutationProjectors'>,
+    evt: MetadataMutationEvent & { body?: unknown },
+): Promise<MutationProjectionOutcome | undefined> {
+    const projector = this.mutationProjectors.get(evt.type);
+    if (!projector) return undefined;
+    try {
+        await projector(evt);
+        return { success: true };
+    } catch (e) {
+        const error = e instanceof Error ? e.message : String(e);
+        console.warn(
+            `[Protocol] mutation projector failed for ${evt.type}/${evt.name} (state=${evt.state}): ${error}`,
+        );
+        return { success: false, error };
+    }
+}
+
+/** The body of `ObjectStackProtocolImplementation#notifyMutationListenersLocal`; the method's docblock there is its contract. */
+export function notifyMutationListenersLocal(
+    this: Pick<MutationFanOutHost, 'metadataMutationListeners'>,
+    evt: MetadataMutationEvent,
+): void {
+    for (const listener of this.metadataMutationListeners) {
+        try {
+            listener(evt);
+        } catch (e) {
+            console.warn(
+                `[Protocol] metadata-mutation listener failed for ${evt.type}/${evt.name}: `
+                + `${e instanceof Error ? e.message : String(e)}`,
+            );
+        }
+    }
+}
+
+/** The body of `ObjectStackProtocolImplementation#publishMetadataMutation`; the method's docblock there is its contract. */
+export function publishMetadataMutation(
+    this: Pick<MutationFanOutHost, 'clusterPubSub' | 'clusterNodeId'>,
+    evt: MetadataMutationEvent,
+): void {
+    if (!this.clusterPubSub) return;
+    if (evt.state === 'draft') return;
+    const payload: ClusterMetadataMutationPayload = {
+        originNode: this.clusterNodeId,
+        event: evt,
+    };
+    void this.clusterPubSub
+        .publish(METADATA_MUTATION_CLUSTER_CHANNEL, payload, {
+            partitionKey: `${evt.type}:${evt.name}`,
+        })
+        .catch((err) => {
+            console.warn(
+                `[Protocol] cluster metadata-mutation publish failed for `
+                + `${evt.type}/${evt.name}: ${err instanceof Error ? err.message : String(err)}`,
+            );
+        });
+}
+
+/** The body of `ObjectStackProtocolImplementation#emitMetaItemPublished`; the method's docblock there is its contract. */
+export async function emitMetaItemPublished(
+    this: Pick<MutationFanOutHost, 'metaItemPublishedListeners'>,
+    evt: MetaItemPublishedEvent,
+): Promise<void> {
+    for (const listener of this.metaItemPublishedListeners) {
+        try {
+            await listener(evt);
+        } catch (e) {
+            console.warn(
+                `[Protocol] the post-publish re-bind announce FAILED for ${evt.type}/${evt.name} — the item IS `
+                + `published and stored, but boot-cached consumers keep the PRE-publish view until this process `
+                + `restarts: a newly published record-triggered flow does not bind its trigger (it will not fire), `
+                + `an edited schedule-triggered flow keeps running its old definition, and authored hooks, actions `
+                + `and translations are not re-synced. Nothing retries this announce. Re-publish the item once the `
+                + `cause below is resolved (it is idempotent), or restart the process to rebuild every subscriber `
+                + `from storage. Cause: ${e instanceof Error ? e.message : String(e)}`,
+            );
+        }
+    }
+}
@@ -417,6 +417,8 @@ import { convertStoredItem, convertStoredItemDetailed } from './protocol-stored-
 import { listLiveMetadataTypes } from './protocol-live-metadata-types.js';
 // [#25467 cut 24] The save door's 409 for a `ConflictError`, with its decision-audit row.
 import { saveConflict } from './protocol-save-conflict.js';
+// [#25467 cut 25] The post-persistence mutation fan-out: projector, local listeners, cluster publish, publish listeners.
+import { emitMetaItemPublished, notifyMutationListenersLocal, publishMetadataMutation, runMutationProjector } from './protocol-mutation-fan-out.js';
 
 /**
  * Canonical Zod schema per metadata type lives in
@@ -7493,18 +7495,12 @@ export class ObjectStackProtocolImplementation implements
     private async runMutationProjector(
         evt: MetadataMutationEvent & { body?: unknown },
     ): Promise<MutationProjectionOutcome | undefined> {
-        const projector = this.mutationProjectors.get(evt.type);
-        if (!projector) return undefined;
-        try {
-            await projector(evt);
-            return { success: true };
-        } catch (e) {
-            const error = e instanceof Error ? e.message : String(e);
-            console.warn(
-                `[Protocol] mutation projector failed for ${evt.type}/${evt.name} (state=${evt.state}): ${error}`,
-            );
-            return { success: false, error };
-        }
+        // [#25467 cut 25] The body moved to `protocol-mutation-fan-out.ts` (see `MutationFanOutHost`).
+        const readMutationProjectors = () => this.mutationProjectors;
+        const host: ThisParameterType<typeof runMutationProjector> = {
+            get mutationProjectors() { return readMutationProjectors(); },
+        };
+        return runMutationProjector.call(host, evt);
     }
 
     /**
@@ -7561,16 +7557,12 @@ export class ObjectStackProtocolImplementation implements
      * messages) could not stop the storm.
      */
     private notifyMutationListenersLocal(evt: MetadataMutationEvent): void {
-        for (const listener of this.metadataMutationListeners) {
-            try {
-                listener(evt);
-            } catch (e) {
-                console.warn(
-                    `[Protocol] metadata-mutation listener failed for ${evt.type}/${evt.name}: `
-                    + `${e instanceof Error ? e.message : String(e)}`,
-                );
-            }
-        }
+        // [#25467 cut 25] The body moved to `protocol-mutation-fan-out.ts` (see `MutationFanOutHost`).
+        const readMetadataMutationListeners = () => this.metadataMutationListeners;
+        const host: ThisParameterType<typeof notifyMutationListenersLocal> = {
+            get metadataMutationListeners() { return readMetadataMutationListeners(); },
+        };
+        return notifyMutationListenersLocal.call(host, evt);
     }
 
     // ── [#13331] Cross-node registry convergence ────────────────────────────
@@ -7673,22 +7665,14 @@ export class ObjectStackProtocolImplementation implements
      * converge on a no-op.
      */
     private publishMetadataMutation(evt: MetadataMutationEvent): void {
-        if (!this.clusterPubSub) return;
-        if (evt.state === 'draft') return;
-        const payload: ClusterMetadataMutationPayload = {
-            originNode: this.clusterNodeId,
-            event: evt,
+        // [#25467 cut 25] The body moved to `protocol-mutation-fan-out.ts` (see `MutationFanOutHost`).
+        const readClusterPubSub = () => this.clusterPubSub;
+        const readClusterNodeId = () => this.clusterNodeId;
+        const host: ThisParameterType<typeof publishMetadataMutation> = {
+            get clusterPubSub() { return readClusterPubSub(); },
+            get clusterNodeId() { return readClusterNodeId(); },
         };
-        void this.clusterPubSub
-            .publish(METADATA_MUTATION_CLUSTER_CHANNEL, payload, {
-                partitionKey: `${evt.type}:${evt.name}`,
-            })
-            .catch((err) => {
-                console.warn(
-                    `[Protocol] cluster metadata-mutation publish failed for `
-                    + `${evt.type}/${evt.name}: ${err instanceof Error ? err.message : String(err)}`,
-                );
-            });
+        return publishMetadataMutation.call(host, evt);
     }
 
     /**
@@ -7862,21 +7846,12 @@ export class ObjectStackProtocolImplementation implements
      * this log.
      */
     private async emitMetaItemPublished(evt: MetaItemPublishedEvent): Promise<void> {
-        for (const listener of this.metaItemPublishedListeners) {
-            try {
-                await listener(evt);
-            } catch (e) {
-                console.warn(
-                    `[Protocol] the post-publish re-bind announce FAILED for ${evt.type}/${evt.name} — the item IS `
-                    + `published and stored, but boot-cached consumers keep the PRE-publish view until this process `
-                    + `restarts: a newly published record-triggered flow does not bind its trigger (it will not fire), `
-                    + `an edited schedule-triggered flow keeps running its old definition, and authored hooks, actions `
-                    + `and translations are not re-synced. Nothing retries this announce. Re-publish the item once the `
-                    + `cause below is resolved (it is idempotent), or restart the process to rebuild every subscriber `
-                    + `from storage. Cause: ${e instanceof Error ? e.message : String(e)}`,
-                );
-            }
-        }
+        // [#25467 cut 25] The body moved to `protocol-mutation-fan-out.ts` (see `MutationFanOutHost`).
+        const readMetaItemPublishedListeners = () => this.metaItemPublishedListeners;
+        const host: ThisParameterType<typeof emitMetaItemPublished> = {
+            get metaItemPublishedListeners() { return readMetaItemPublishedListeners(); },
+        };
+        return emitMetaItemPublished.call(host, evt);
     }
 
     /**