OpenAI Codex

OpenAI Codex

The OpenAI Codex integration gives Ptah access to the GPT-5 family and Codex CLI agents with reasoning-effort control.

What you need

• An OpenAI account with API access from the OpenAI Platform, or a ChatGPT subscription for the OAuth path.

Configuration

You have two ways to authenticate:

API key (direct)

1. Create an API key at platform.openai.com.
2. Open Settings → Providers → OpenAI Codex.
3. Paste the key. It’s stored in encrypted safeStorage.

OAuth (ChatGPT subscription)

Pro tier

The Codex OAuth flow (using your ChatGPT subscription for API-style access) is a Ptah Pro feature.

1. Open Settings → Providers → OpenAI Codex.
2. Click Sign in with ChatGPT.
3. Approve the Ptah app in your browser.

Non-secret Codex settings live in ~/.ptah/settings.json:

{
  "provider.openai-codex.oauthApiEndpoint": "",
  "provider.openai-codex.modelTier.opus": null,
  "provider.openai-codex.modelTier.sonnet": null,
  "provider.openai-codex.modelTier.haiku": null,
  "agentOrchestration.codexModel": "",
  "agentOrchestration.codexReasoningEffort": "",
  "agentOrchestration.codexAutoApprove": true
}

• codexReasoningEffort accepts "low", "medium", or "high" (empty string uses the in-chat effort level).
• codexAutoApprove: true lets the Codex CLI auto-approve sandbox operations; set to false to require manual approval.

Verifying it works

1. Open the chat.
2. Select a GPT-5 or Codex model.
3. Send a prompt that requires reasoning: Explain the time complexity of quicksort with and without the median-of-three optimization.
4. You should see a streaming response with thinking tokens visible in the Execution Tree.

Troubleshooting

• invalid_api_key — regenerate the key at platform.openai.com.
• model_not_available — your org may not have GPT-5 access yet. Try gpt-4o or request access.
• Codex CLI not detected as a sub-agent — make sure the Codex CLI is installed and on your PATH, then restart Ptah. Check that codex isn’t in agentOrchestration.disabledClis.
• OAuth sign-in fails — requires a ChatGPT Plus/Team/Enterprise plan. Free ChatGPT accounts can’t use the OAuth path; use an API key instead.