fx
A tiny, open, native coding agent from Vercel Labs that can run on your ChatGPT subscription.
About fx
fx is an experimental coding agent CLI from Vercel Labs, written in Zig: a small native binary that is open source, model-agnostic and embeddable as a harness in larger systems. You can add your own tools and connect skills or MCP servers. It works with local models, gateways, direct provider APIs or subscriptions, and fx login codex signs in with your ChatGPT subscription.
Can you use your ChatGPT plan in fx?
Yes. Your ChatGPT subscription, via fx login codex. fx's own page says: "fx login codex: ChatGPT subscription (OpenAI Codex OAuth)"
How to connect your plan
ChatGPT Plus or Pro
- Run fx login codex and sign in with ChatGPT.
