diff --git a/src/agents/subagent-registry.persistence.test.ts b/src/agents/subagent-registry.persistence.test.ts
index 3cb1e4a2ea3..36663b709b0 100644
--- a/src/agents/subagent-registry.persistence.test.ts
+++ b/src/agents/subagent-registry.persistence.test.ts
@@ -499,6 +499,45 @@ describe("subagent registry persistence", () => {
     expect(listSubagentRunsForRequester("agent:main:main")).toHaveLength(0);
   });
 
+  it("removes attachments when pruning orphaned restored runs", async () => {
+    const persisted = createPersistedEndedRun({
+      runId: "run-orphan-attachments",
+      childSessionKey: "agent:main:subagent:ghost-attachments",
+      task: "orphan attachments",
+      cleanup: "delete",
+    });
+    const registryPath = await writePersistedRegistry(persisted, {
+      seedChildSessions: false,
+    });
+    if (!tempStateDir) {
+      throw new Error("tempStateDir not initialized");
+    }
+    const attachmentsRootDir = path.join(tempStateDir, "attachments");
+    const attachmentsDir = path.join(attachmentsRootDir, "ghost");
+    await fs.mkdir(attachmentsDir, { recursive: true });
+    await fs.writeFile(path.join(attachmentsDir, "artifact.txt"), "artifact", "utf8");
+    const parsed = JSON.parse(await fs.readFile(registryPath, "utf8")) as {
+      runs?: Record<string, Record<string, unknown>>;
+    };
+    if (!parsed.runs?.["run-orphan-attachments"]) {
+      throw new Error("expected orphaned run in persisted registry");
+    }
+    parsed.runs["run-orphan-attachments"] = {
+      ...parsed.runs["run-orphan-attachments"],
+      attachmentsRootDir,
+      attachmentsDir,
+    };
+    await fs.writeFile(registryPath, `${JSON.stringify(parsed)}\n`, "utf8");
+
+    await restartRegistryAndFlush();
+
+    await expect(fs.access(attachmentsDir)).rejects.toMatchObject({ code: "ENOENT" });
+    const after = JSON.parse(await fs.readFile(registryPath, "utf8")) as {
+      runs?: Record<string, unknown>;
+    };
+    expect(after.runs?.["run-orphan-attachments"]).toBeUndefined();
+  });
+
   it("prefers active runs and can resolve them from persisted registry snapshots", async () => {
     const childSessionKey = "agent:main:subagent:disk-active";
     await writePersistedRegistry(
diff --git a/src/agents/subagent-registry.ts b/src/agents/subagent-registry.ts
index 2e5967550dd..8ec9459b3b8 100644
--- a/src/agents/subagent-registry.ts
+++ b/src/agents/subagent-registry.ts
@@ -287,6 +287,11 @@ function reconcileOrphanedRun(params: {
     params.entry.cleanupCompletedAt = now;
     changed = true;
   }
+  const shouldDeleteAttachments =
+    params.entry.cleanup === "delete" || !params.entry.retainAttachmentsOnKeep;
+  if (shouldDeleteAttachments) {
+    void safeRemoveAttachmentsDir(params.entry);
+  }
   const removed = subagentRuns.delete(params.runId);
   resumedRuns.delete(params.runId);
   if (!removed && !changed) {