abhigyanpatwari/GitNexus · error · Error

codex CLI returned empty output

Error message

codex CLI returned empty output

What it means

The codex CLI ran (`codex exec --sandbox read-only --cd <dir>`), then the client reads last-message.txt from the temp output dir and falls back to captured stdout; if both are empty/whitespace after trim, it throws. Codex is expected to write its final message to the output file — empty file plus empty stdout means the exec produced no final answer.

Source

Thrown at gitnexus/src/core/wiki/local-cli-client.ts:158

    '-c',
    'approval_policy="never"',
    '--color',
    'never',
    '--output-last-message',
    outputPath,
  ];

  if (config.model) {
    args.push('--model', config.model);
  }
  args.push('-');

  try {
    const response = await runLocalCLI('codex', commandInfo, args, config, fullPrompt, options);
    const lastMessage = await fs.readFile(outputPath, 'utf-8').catch(() => '');
    const content = (lastMessage || response.content).trim();
    if (!content) {
      throw new Error('codex CLI returned empty output');
    }
    return { content };
  } finally {
    await fs.rm(outputDir, { recursive: true, force: true }).catch(() => undefined);
  }
}

interface OpenCodeEvent {
  type?: string;
  message?: string;
  error?: {
    message?: string;
    name?: string;
    data?: {
      message?: string;
    };
  };
  part?: {

View on GitHub (pinned to aac7515d2a)

Solutions

1. Verify the CLI produces output manually: `codex exec 'say hi'` and check a non-empty final message
2. Complete `codex` login/consensus auth, then rerun the wiki command
3. Update or pin a known-good Codex CLI version if a release changed exec output behavior
4. Retry with `-v` (GITNEXUS_VERBOSE=1) to inspect the exact command and captured output

Example fix

# before
gitnexus wiki --provider codex   # empty output

# after
codex exec 'say hi'   # confirm non-empty final message
gitnexus wiki --provider codex -v

try {
  await callCodexLLM(prompt, config);
} catch (err) {
  if (err instanceof Error && err.message === 'codex CLI returned empty output') {
    return callCodexLLM(prompt, config); // retry once — exec sometimes yields no final message
  }
  throw err;
}

When it happens

Trigger: Codex exec finishes without writing last-message.txt (auth failure, sandbox denial, model refusal with no text, or a CLI arg-schema change across versions making the invocation a no-op); stdout also empty so the fallback yields nothing.

Common situations: Codex CLI not signed in (exec exits quietly); version upgrades renaming the output-file convention or flags; read-only sandbox blocking a step the model insisted on, ending with no final message; prompt too large.

Related errors

• LLM returned empty response
• LLM returned empty streaming response
• claude CLI returned empty output
• Codex CLI not found. Install Codex CLI and ensure `codex` is
• --allow-insecure-connection / GITNEXUS_ALLOW_INSECURE_CONNEC

AI-assisted analysis of abhigyanpatwari/GitNexus@aac7515d2a (2026-08-20). Data as JSON: /api/errors/ba567c41eb1273be. Report an issue: GitHub.