OVTH / 2026 LIVE · V0.4.0
Ø Overthinking Gateway ↗

OpenAI Codex CLI in 2026

OAuth once, run forever. Codex CLI's interactive mode finally feels like a first-class Claude Code peer.

⚡ 3min read beginner OS · macos · linux · windows v1.3.0 Last updated May 09, 2026 · by xlrd

Prereq

  • Node.js 20+
  • OpenAI account with ChatGPT Pro or an API key
  • A repo to test in

Steps

01. Install

bash 
npm install -g @openai/codex
codex --version  # 1.3.0

02. OAuth once

bash 
codex login
# opens a browser, auth'd session stored in ~/.codex/auth.json

If you’d rather use an API key: codex login --api-key sk-....

03. Start interactive mode

bash 
cd ~/projects/your-app
codex

You get a REPL with file awareness, slash commands, and streaming output.

04. Work with slash commands

bash 
/model gpt-5.4       # switch model
/add src/**/*.ts     # scope the repo view
/shell npm test      # run a command, pipe output back
/undo                # revert last edit
/exit

05. Pipe it in CI

bash 
codex exec --model gpt-5.4-mini \
--task "update all imports from lodash to es-toolkit" \
--allow-write "src/**"

Non-interactive mode writes a JSON summary to stdout. Easy to parse in a GH Action.

Next

  • Codex in GitHub Actions
  • Dual-wield with Claude Code
Feedback · anonymous
Was this helpful?