Codex CLI

OpenAI's Codex CLI provides access to GPT-4o and other OpenAI models. It is the default backend and offers reliable, versatile performance for general security analysis.

Setup

1. Install the CLI: Follow the official OpenAI Codex documentation.

   npm install -g @openai/codex

2. Set your API key:

   export OPENAI_API_KEY="sk-..."

3. Verify it works: Test in your terminal:

   codex "hello"

4. Configure in Burp: Open Burp AI Agent → Settings → AI Backend and set:

Setting	Value
Preferred Backend	Codex CLI (select from dropdown)
Codex CLI Command	codex chat (default)

To specify a model, include the flag in the command field:

Setting	Value
Codex CLI Command	codex --model gpt-5.2

Troubleshooting

• "command not found": Ensure codex is installed and in your system PATH.

• Authentication errors: Verify your OPENAI_API_KEY environment variable is set.

• Rate limiting: OpenAI applies rate limits based on your plan tier. Check usage at platform.openai.com.