This window's Goose backend stopped. Close this window and o

Error message

This window's Goose backend stopped. Close this window and open a new chat to start a new backend. If this keeps happening, restart Goose Desktop.

What it means

The lease registry maps each renderer window to its goose serve lease. getAcpUrl(windowId) throws GOOSE_SERVE_EXITED_USER_MESSAGE when the lease exists but its backing `goose serve` process has exited (the lease's 'exit' listener fired or hasExited() was true at creation). It is a user-facing message by design: the window must be closed and a new chat opened to spawn a fresh backend.

Source

Thrown at ui/desktop/src/gooseServeLeaseRegistry.ts:100

      windowIds: new Set<number>(),
      cleanedUp: false,
      exited: false,
      exitCode: null,
      exitSignal: null,
    };
  }

  get(windowId: number): GooseServeLease | null {
    return this.leasesByWindowId.get(windowId) ?? null;
  }

  getAcpUrl(windowId: number): string | null {
    const lease = this.get(windowId);
    if (!lease) {
      return null;
    }
    if (lease.exited) {
      throw new Error(GOOSE_SERVE_EXITED_USER_MESSAGE);
    }
    return lease.acpUrl;
  }

  getSecretKey(windowId: number): string | null {
    const lease = this.get(windowId);
    if (!lease) {
      return null;
    }
    if (lease.exited) {
      throw new Error(GOOSE_SERVE_EXITED_USER_MESSAGE);
    }
    return lease.secretKey;
  }

  attachWindow(windowId: number, lease: GooseServeLease) {
    lease.windowIds.add(windowId);
    this.leasesByWindowId.set(windowId, lease);

View on GitHub (pinned to 3810898a74)

Solutions

Catch this error in the IPC handler and surface the message to the renderer so the user closes the window / opens a new chat
Inspect the main-process log for 'Goose ACP server exited unexpectedly' (logged with exit code, signal, windowIds) to find why the process died
If exits recur, check exitCode/signal: non-zero codes point at goose crashes — update the binary or reduce memory pressure; SIGKILL usually means OOM
Ensure releaseWindow is called when windows close so stale exited leases are not reused

Defensive patterns

Strategy: type-guard

Validate before calling

const lease = leaseRegistry.get(windowId);
if (!lease || lease.exited) {
  // surface GOOSE_SERVE_EXITED_USER_MESSAGE or tear down the window; do not call getAcpUrl
}

Type guard

const hasLiveLease = (windowId: number): boolean => {
  const lease = leaseRegistry.get(windowId);
  return lease !== null && !lease.exited;
};

Try / catch

try {
  acpUrl = leaseRegistry.getAcpUrl(windowId);
} catch (e) {
  if (e instanceof Error && e.message === GOOSE_SERVE_EXITED_USER_MESSAGE) {
    return { error: e.message }; // IPC-safe: renderer shows 'open a new chat'
  }
  throw e;
}

Prevention

Check lease.exited before every getAcpUrl/getSecretKey call in IPC handlers
Subscribe to process 'exit' on the lease to proactively notify the window instead of failing on next request
Always pair attachWindow with releaseWindow so exited leases are never reused

When it happens

Trigger: The ACP server process crashes or is killed (OOM, signal, panic) after the window connected; shutdown initiated while a renderer still calls getAcpUrl; any IPC handler that resolves the backend URL for a window whose process died between calls.

Common situations: Backend segfault or panic mid-session; user's machine suspends and the child is reaped; antivirus or process cleaners killing goose; tests that stop the serve process then keep using the registry.

Related errors

AI-assisted analysis of aaif-goose/goose@3810898a74 (2026-08-16). Data as JSON: /api/errors/35ee22ff63193519. Report an issue: GitHub.