Codex Q&A

Use OpenAI’s Codex CLI to answer questions about the codebase.

Prerequisites

Codex CLI must be installed and configured:

npm install -g @openai/codex
# or
brew install --cask codex

An OpenAI API key must be configured (OPENAI_API_KEY environment variable or via codex initial setup).

Usage

Spawn the codex-qa subagent to handle the question:

Use the Task tool to spawn the codex-qa agent with the user's question.

The subagent will:

1. Formulate a clear prompt for Codex
2. Run codex exec "question" in read-only mode
3. Return Codex’s response

Direct Usage (without subagent)

If you prefer to run Codex directly:

codex exec "your question here"

Command Options

• Basic query: codex exec "question"
• With image: codex -i image.png exec "question about image"
• JSON output: codex exec --json "question"
• Longer timeout: codex exec --timeout 300000 "complex question"

Common Use Cases

• Code explanation: “What does this function do?”
• Architecture questions: “How is the database layer structured?”
• Finding patterns: “Where is error handling implemented?”
• Code review: “Review this file for potential issues”
• Comparison: Get a second opinion on a code question

Notes

• Codex exec runs in read-only mode by default – it cannot modify files
• Activity streams to stderr, final answer goes to stdout
• For complex questions, use the subagent for better context isolation