paperclipai/paperclip · error · Error

Sandbox callback bridge did not report a listening port.

Error message

Sandbox callback bridge did not report a listening port.

What it means

Startup validation of the sandbox callback bridge: the readiness JSON parsed but contained no usable listening port (and no valid host/baseUrl), so the host cannot target the bridge inside the sandbox.

Solutions

1. Retry starting the bridge; check logs for why no listening port was reported.

When it happens

Trigger: Thrown at packages/adapter-utils/src/sandbox-callback-bridge.ts:1670 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of paperclipai/paperclip@3f1d897a7c (2026-08-18). Data as JSON: /api/errors/f6863f2695d08c17. Report an issue: GitHub.

Appendix: source

Thrown at packages/adapter-utils/src/sandbox-callback-bridge.ts:1810

}): Promise<StartedSandboxCallbackBridgeServer> {
  const timeoutMs = normalizeTimeoutMs(input.timeoutMs, DEFAULT_BRIDGE_RESPONSE_TIMEOUT_MS);
  const shellCommand = preferredShellForSandbox(input.shellCommand);
  const directories = sandboxCallbackBridgeDirectories(input.queueDir);
  let remoteEntrypoint = path.posix.join(input.assetRemoteDir, SANDBOX_CALLBACK_BRIDGE_ENTRYPOINT);
  if (input.bridgeAsset) {
    const assetSync = await syncSandboxCallbackBridgeEntrypoint({
      runner: input.runner,
      remoteCwd: input.remoteCwd,
      assetRemoteDir: input.assetRemoteDir,
      bridgeAsset: input.bridgeAsset,
      timeoutMs,
      shellCommand,
    });
    remoteEntrypoint = assetSync.remoteEntrypoint;
  }
  const env = buildSandboxCallbackBridgeEnv({
    queueDir: input.queueDir,
    bridgeToken: input.bridgeToken,
    host: input.host,
    port: input.port,
    pollIntervalMs: input.pollIntervalMs,
    responseTimeoutMs: input.responseTimeoutMs,
    maxQueueDepth: input.maxQueueDepth,
    maxBodyBytes: input.maxBodyBytes,
  });
  const nodeCommand = input.nodeCommand?.trim() || "node";
  const startResult = await input.runner.execute({
    command: shellCommand,
    args: shellCommandArgs(
      [
        `mkdir -p ${shellQuote(directories.requestsDir)} ${shellQuote(directories.responsesDir)} ${shellQuote(directories.logsDir)}`,
        `rm -f ${shellQuote(directories.readyFile)} ${shellQuote(directories.pidFile)}`,
        `nohup ${shellQuote(nodeCommand)} ${shellQuote(remoteEntrypoint)} ` +
          `>> ${shellQuote(directories.logFile)} 2>&1 < /dev/null &`,
        "pid=$!",
        `printf '%s\\n' \"$pid\" > ${shellQuote(directories.pidFile)}`,

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