diff --git a/server/src/__tests__/agent-directory-lock-crash-point.test.ts b/server/src/__tests__/agent-directory-lock-crash-point.test.ts
new file mode 100644
index 00000000000..85f87a86fb8
--- /dev/null
+++ b/server/src/__tests__/agent-directory-lock-crash-point.test.ts
@@ -0,0 +1,31 @@
+import { mkdtemp, rm, writeFile } from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+describe("directory-lock crash point", () => {
+  let root: string | null = null;
+
+  afterEach(async () => {
+    vi.unstubAllEnvs();
+    vi.resetModules();
+    if (root) await rm(root, { recursive: true, force: true });
+    root = null;
+  });
+
+  it("fails with the lock's own busy error, so preparation defers it like real contention", async () => {
+    root = await mkdtemp(path.join(os.tmpdir(), "directory-lock-crash-point-"));
+    const control = path.join(root, "crash-point.control");
+    await writeFile(control, "t1 agent_directory.operation_lock.before_acquire:1 fail\n");
+    vi.stubEnv("PAPERCLIP_CRASH_POINT_CONTROL", control);
+    vi.stubEnv("PAPERCLIP_EPHEMERAL_SERVER", "true");
+    vi.resetModules();
+    const { agentDirectoryWorkingCopyService, AgentDirectoryOperationBusyError } = await import("../services/agent-directory-working-copies.js");
+    const { prepareWithAgentDirectoryDeferral, AgentDirectoryPreparationDeferral } = await import("../services/heartbeat/agent-directory-busy.js");
+    const service = agentDirectoryWorkingCopyService({} as never, async () => null, async row => row);
+    const row = { companyId: "company-1", runId: "run-1", agentId: "agent-1", location: "remote:sandbox-1", receipt: {} };
+    const failure = service.collectStopped(row as never);
+    await expect(failure).rejects.toBeInstanceOf(AgentDirectoryOperationBusyError);
+    await expect(prepareWithAgentDirectoryDeferral(() => failure)).rejects.toBeInstanceOf(AgentDirectoryPreparationDeferral);
+  });
+});
diff --git a/server/src/services/agent-directory-working-copies.ts b/server/src/services/agent-directory-working-copies.ts
index 8109e1ef45b..98ec9ab4ec8 100644
--- a/server/src/services/agent-directory-working-copies.ts
+++ b/server/src/services/agent-directory-working-copies.ts
@@ -659,7 +659,7 @@ export function agentDirectoryWorkingCopyService(db: Db, get: (companyId: string
     // Different controllers have different cache roots. Serialize their active
     // collection/cleanup operations in Postgres, without holding row locks over I/O.
     // Test instrumentation only (disarmed in production): restart chaos fails the Nth attempt with the lock's own conflict.
-    crashPoint("agent_directory.operation_lock.before_acquire", { fail: () => conflict("Agent directory operation is already active") });
+    crashPoint("agent_directory.operation_lock.before_acquire", { fail: () => new AgentDirectoryOperationBusyError() });
     return withDedicatedDbConnection(db, dedicated => dedicated.transaction(async tx => {
       const [lock] = await tx.execute(sql`select pg_try_advisory_xact_lock(hashtextextended(${`agent-directory:${row.companyId}:${row.agentId}`}, 0)) as acquired,
         (select setting::bigint from pg_settings where name = 'idle_in_transaction_session_timeout') as idle_timeout_ms`);