OpenAI Codex CLI

Codex CLI is OpenAI's open-source agentic coding tool. It connects to AgentXchain via the local_cli adapter.

Which adapter?

local_cli — AgentXchain spawns codex as a subprocess for each governed turn.

Prerequisites

• Codex CLI installed (npm install -g @openai/codex)
• OPENAI_API_KEY set in your environment
• agentxchain CLI installed

Configuration

{
  "runtimes": {
    "codex-dev": {
      "type": "local_cli",
      "command": ["codex", "--quiet", "--full-auto"],
      "cwd": ".",
      "prompt_transport": "argv"
    }
  },
  "roles": {
    "dev": {
      "runtime": "codex-dev",
      "mandate": "Implement features and fix bugs",
      "authority": "proposed"
    }
  }
}

Key fields

Field	Value	Why
command	["codex", "--quiet", "--full-auto"]	--quiet suppresses interactive output. --full-auto allows file writes without confirmation.
prompt_transport	"argv"	The prompt is passed as a command-line argument. Use "stdin" if your Codex version supports piped input.

Verify the connection

agentxchain connector check

Minimal working example

mkdir my-project && cd my-project
agentxchain init --governed --template cli-tool --goal "Build a JSON schema validator" -y
git init && git add -A && git commit -m "initial scaffold"
agentxchain run

Gotchas

• --full-auto is required for non-interactive governed execution. Without it, Codex will prompt for approval on file changes.
• Model selection: Codex CLI defaults to a Codex-optimized model. You can override with --model gpt-5.4 if needed, but the default is usually better for coding tasks.
• Working directory: Codex CLI operates on the current working directory. The cwd field ensures it runs in your project root.