Codex

Use OpenAI's Codex CLI with Verun — prerequisites, selecting the agent, and Verun-specific configuration.

Codex is OpenAI's CLI-based coding agent. It provides code generation and editing capabilities powered by OpenAI's models.

Overview

Codex CLI runs as a terminal process that Verun manages inside each task's worktree. It can read your codebase, generate code, and execute terminal commands within the isolated worktree.

Prerequisites

Codex CLI installed
An active OpenAI API key
Node.js 18+

Verify the CLI is available:

codex --version

Selecting Codex in Verun

Open a task and click the + button in the session list.
Select Codex from the agent menu.
Optionally pick a model from the submenu.
The session opens and Codex begins in the task's worktree.

Alternatively, set Codex as the default in .verun.json:

{
  "defaultAgentType": "codex"
}

Configuration

Codex CLI uses environment variables and its own config files for project-specific behavior. Place configuration in your project root — it is available inside each worktree.

Verun-specific settings via .verun.json:

{
  "agent": "openai-codex",
  "setup": ["npm install"],
  "ports": [3000]
}

Known Limitations

Codex CLI requires an active internet connection to communicate with OpenAI's API.
The CLI must be installed and your API key configured before starting a Verun session — Verun does not manage CLI authentication.