diff --git a/doc/AGENT-ARTIFACTS.md b/doc/AGENT-ARTIFACTS.md
index f5c12fdaf9c..cb87f4d8bb9 100644
--- a/doc/AGENT-ARTIFACTS.md
+++ b/doc/AGENT-ARTIFACTS.md
@@ -27,6 +27,12 @@ remote workspace. Supply a workspace-relative `contentRef`, basename `filename`,
 The tool verifies the file, stores an attachment and artifact work product, and
 binds it to the response. Generic API tools and a legacy API key are unnecessary.
 
+`register_deliverable` stores the file on its current task. A completion report
+can also cite a file on a direct child task that is done, because the child's
+own completion verified that file. A parent that delegated a file to a child
+links the child's file and does not register a copy. The child's file does not
+count as delivery of a file that the parent's own request names.
+
 Named JSON file outputs and explicit publication requests require the same
 verified delivery evidence as other file outputs. A saved summary document does
 not replace a requested downloadable JSON file. Reading JSON inputs or discussing
diff --git a/server/src/services/native-runtime/native-deliverable-feedback.ts b/server/src/services/native-runtime/native-deliverable-feedback.ts
index bad131e5af9..ba36256ccd5 100644
--- a/server/src/services/native-runtime/native-deliverable-feedback.ts
+++ b/server/src/services/native-runtime/native-deliverable-feedback.ts
@@ -324,6 +324,20 @@ export async function publishedTaskDocuments(db: Db, binding: { companyId: strin
     href: `/${encodeURIComponent(issuePrefix)}/issues/${encodeURIComponent(issueIdentifier ?? binding.issueId)}#document-${encodeURIComponent(key)}` }));
 }
 
+/** A parent that delegated a file to a child links the child's delivered file
+ * instead of publishing a copy, because native register_deliverable is bound to
+ * its current task. A completed direct child's attachment is a valid citation,
+ * but not this run's publication of a file that the parent itself requests.
+ */
+async function completedChildAttachment(db: Db, binding: { companyId: string; issueId: string; lockSources?: boolean }, id: string): Promise<boolean> {
+  const query = db.select({ id: issueAttachments.id }).from(issueAttachments)
+    .innerJoin(issues, and(eq(issues.id, issueAttachments.issueId), eq(issues.companyId, binding.companyId),
+      eq(issues.parentId, binding.issueId), eq(issues.status, "done")))
+    .where(and(eq(issueAttachments.id, id), eq(issueAttachments.companyId, binding.companyId))).limit(1);
+  const [attachment] = await (binding.lockSources ? query.for("share", { of: [issueAttachments, issues], noWait: true }) : query);
+  return attachment !== undefined;
+}
+
 /** Files cited as completed output must be reachable outside the agent workspace. */
 export async function validateNativeDeliverableEvidence(
   db: Db,
@@ -358,7 +372,8 @@ export async function validateNativeDeliverableEvidence(
       const [attachment] = uuid.test(id)
         ? await (binding.lockSources ? query.for("share", { of: [issueAttachments, assets], noWait: true }) : query) : [];
       if (!attachment) {
-        throw new NativeDeliverableEvidenceError("Completion cites no registered attachment on this task. Use register_deliverable for the requested file and cite deliverable:<attachmentId> from its receipt. No human completion approval was created.");
+        if (uuid.test(id) && await completedChildAttachment(db, binding, id)) continue;
+        throw new NativeDeliverableEvidenceError("Completion cites no registered attachment on this task or its completed child tasks. Use register_deliverable for the requested file and cite deliverable:<attachmentId> from its receipt. No human completion approval was created.");
       }
       // A prior output (or user input) can be useful context, but does not prove
       // this run published the newly requested output. The receipt survives a
diff --git a/server/src/services/native-runtime/native-runner-file-handoff.test.ts b/server/src/services/native-runtime/native-runner-file-handoff.test.ts
index a01a17d0dd7..e7c166fd71c 100644
--- a/server/src/services/native-runtime/native-runner-file-handoff.test.ts
+++ b/server/src/services/native-runtime/native-runner-file-handoff.test.ts
@@ -32,6 +32,7 @@ import {
   issueComments,
   issues,
   issueWorkProducts,
+  type Db,
 } from "@paperclipai/db";
 
 import { startEmbeddedPostgresTestDatabase } from "../../__tests__/helpers/embedded-postgres.js";
@@ -45,6 +46,7 @@ import {
   stageNativeRunnerAttachmentBytes,
   stageNativeRunnerWakeAttachments,
 } from "./native-runner-file-handoff.js";
+import { validateNativeDeliverableEvidence } from "./native-deliverable-feedback.js";
 import { PaperclipRunnerToolAuthority } from "./paperclip-runner-tool-authority.js";
 
 describe("native runner file handoff", () => {
@@ -461,7 +463,26 @@ describe("native runner file handoff", () => {
     try {
       await expect(nativeCompletionFeedback(db, runId, doneReport([`deliverable:${first.entityRefs[0]}`])))
         .rejects.toThrow("registered attachment on this task");
+      // A parent links the file its completed child delivered. It cannot
+      // register that file again, because register_deliverable is task-bound.
+      await db.update(issues).set({ parentId: issueId }).where(eq(issues.id, otherIssueId));
+      await expect(nativeCompletionFeedback(db, runId, doneReport([`deliverable:${first.entityRefs[0]}`])))
+        .rejects.toThrow("registered attachment on this task");
+      await db.update(issues).set({ status: "done" }).where(eq(issues.id, otherIssueId));
+      await db.update(issues).set({ title: "Review the delegated work" }).where(eq(issues.id, issueId));
+      await expect(nativeCompletionFeedback(db, runId, doneReport([`/api/attachments/${first.entityRefs[0]}/content`])))
+        .resolves.toContain("Completion report accepted");
+      await expect(db.transaction(tx => validateNativeDeliverableEvidence(tx as unknown as Db, {
+        companyId, issueId, runId, objective: "Review the delegated work", semanticToolReceipts: {},
+        lockSources: true, authoritativeDone: true,
+      }, doneReport([`deliverable:${first.entityRefs[0]}`])))).resolves.toBeUndefined();
+      // The child's file is context, not this run's publication of a file the
+      // parent's own request names.
+      await db.update(issues).set({ title: "Prepare a requested file" }).where(eq(issues.id, issueId));
+      await expect(nativeCompletionFeedback(db, runId, doneReport([`deliverable:${first.entityRefs[0]}`])))
+        .rejects.toThrow("no accessible delivery evidence");
     } finally {
+      await db.update(issues).set({ title: "Prepare a requested file" }).where(eq(issues.id, issueId));
       await db.update(issueAttachments).set({ issueId }).where(eq(issueAttachments.id, first.entityRefs[0]));
       await db.delete(issues).where(eq(issues.id, otherIssueId));
     }