@@ -0,0 +1,88 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * [#25467 cut 19] A package write's validation scope, as
+ * `ObjectStackProtocolImplementation` resolves it
+ * (`resolveWritePackageScope`): the written package and the closure of the
+ * dependencies its manifest declares, read from the registry, or `undefined`
+ * wherever that cannot be read. Moved out of `protocol.ts` whole.
+ *
+ * A MOVE, not a redesign. The 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 guards, the same
+ * dependency walk, and the same silent `catch` answering `undefined`.
+ *
+ * ## How the moved body reaches 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 the method — the published `dist/*.d.ts` lists its name,
+ * docblock and declared signature — and its body is one literal of exactly
+ * the {@link WritePackageScopeHost} members it reads, plus a `.call`. The
+ * engine is handed over as a getter, so the body reads the protocol's engine
+ * (and so its registry) at call time. Every other reader of the method keeps
+ * calling the class method: `tenantAuthoredWriteRefusal`, and the authoring
+ * gate's host (cut 8, `protocol-authoring-gate.ts`), whose closure calls it.
+ *
+ * The body reads no module-level declaration of `protocol.ts` and no import,
+ * so this module imports only the class type. Nothing re-exports this module,
+ * so the published surface does not move.
+ */
+
+import type { ObjectStackProtocolImplementation } from './protocol.js';
+
+/**
+ * The `ObjectStackProtocolImplementation` members the function below reads —
+ * every one of them, and no other; the 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 signature on the class is a change
+ * here too, and naming a member the class does not have is a compile error.
+ */
+export interface WritePackageScopeHost {
+    readonly engine: ObjectStackProtocolImplementation['engine'];
+}
+
+/** The body of `ObjectStackProtocolImplementation#resolveWritePackageScope`; the method's docblock there is its contract. */
+export function resolveWritePackageScope(
+    this: Pick<WritePackageScopeHost, 'engine'>,
+    packageId: string | null | undefined,
+): { packageId: string; dependencies: string[] } | undefined {
+    if (typeof packageId !== 'string' || packageId === '' || packageId === 'sys_metadata') return undefined;
+    try {
+        const registry = this.engine.registry as
+            | { getPackage?: (id: string) => { manifest?: unknown } | undefined }
+            | undefined;
+        if (typeof registry?.getPackage !== 'function') return undefined;
+        // The written package itself must be readable: its manifest is the
+        // ONLY declaration of what it may reference, and narrowing without
+        // it would be narrowing on nothing.
+        if (!registry.getPackage(packageId)) return undefined;
+
+        const dependencies = new Set<string>();
+        const frontier = [packageId];
+        while (frontier.length > 0) {
+            const current = frontier.pop() as string;
+            const manifest = registry.getPackage(current)?.manifest as
+                | { dependencies?: Record<string, unknown> }
+                | undefined;
+            const declared = manifest?.dependencies;
+            if (!declared || typeof declared !== 'object') continue;
+            for (const dep of Object.keys(declared)) {
+                // A dependency the registry cannot resolve is still IN the
+                // closure: the package declared it, so an object stamped
+                // with it is reachable by declaration. Only the transitive
+                // walk stops there — `getPackage` returns undefined and the
+                // loop above simply contributes nothing further.
+                if (dep === packageId || dependencies.has(dep)) continue;
+                dependencies.add(dep);
+                frontier.push(dep);
+            }
+        }
+        return { packageId, dependencies: [...dependencies] };
+    } catch {
+        // Context gathering must never fail a write (the same contract
+        // `listCollection` above holds). An unreadable registry means an
+        // unnarrowed gate, not a refused publish.
+        return undefined;
+    }
+}
@@ -402,6 +402,8 @@ import { namesWithOwnStoredRow, readActiveOverlayRows, readItemActiveRows, store
 import { classifyObjectContribution, releaseAdoptedObjectOwner } from './protocol-object-owner.js';
 // [#25467 cut 18] The flow save's retired-spelling replay verdict (#23903 ruling B′): does a save newly introduce a retired spelling no stored row carries.
 import { flowSaveReplaysRetired } from './protocol-flow-save-replay.js';
+// [#25467 cut 19] A package write's validation scope: the written package and its declared dependency closure, from the registry.
+import { resolveWritePackageScope } from './protocol-write-package-scope.js';
 
 /**
  * Canonical Zod schema per metadata type lives in
@@ -7361,44 +7363,12 @@ export class ObjectStackProtocolImplementation implements
     private resolveWritePackageScope(
         packageId: string | null | undefined,
     ): { packageId: string; dependencies: string[] } | undefined {
-        if (typeof packageId !== 'string' || packageId === '' || packageId === 'sys_metadata') return undefined;
-        try {
-            const registry = this.engine.registry as
-                | { getPackage?: (id: string) => { manifest?: unknown } | undefined }
-                | undefined;
-            if (typeof registry?.getPackage !== 'function') return undefined;
-            // The written package itself must be readable: its manifest is the
-            // ONLY declaration of what it may reference, and narrowing without
-            // it would be narrowing on nothing.
-            if (!registry.getPackage(packageId)) return undefined;
-
-            const dependencies = new Set<string>();
-            const frontier = [packageId];
-            while (frontier.length > 0) {
-                const current = frontier.pop() as string;
-                const manifest = registry.getPackage(current)?.manifest as
-                    | { dependencies?: Record<string, unknown> }
-                    | undefined;
-                const declared = manifest?.dependencies;
-                if (!declared || typeof declared !== 'object') continue;
-                for (const dep of Object.keys(declared)) {
-                    // A dependency the registry cannot resolve is still IN the
-                    // closure: the package declared it, so an object stamped
-                    // with it is reachable by declaration. Only the transitive
-                    // walk stops there — `getPackage` returns undefined and the
-                    // loop above simply contributes nothing further.
-                    if (dep === packageId || dependencies.has(dep)) continue;
-                    dependencies.add(dep);
-                    frontier.push(dep);
-                }
-            }
-            return { packageId, dependencies: [...dependencies] };
-        } catch {
-            // Context gathering must never fail a write (the same contract
-            // `listCollection` above holds). An unreadable registry means an
-            // unnarrowed gate, not a refused publish.
-            return undefined;
-        }
+        // [#25467 cut 19] The body moved to `protocol-write-package-scope.ts` (see `WritePackageScopeHost`).
+        const readEngine = () => this.engine;
+        const host: ThisParameterType<typeof resolveWritePackageScope> = {
+            get engine() { return readEngine(); },
+        };
+        return resolveWritePackageScope.call(host, packageId);
     }
 
     /**