duolahypercho/codex-router ? reverse-engineered prompt

Build me a local model router for Codex that lets me use external models like Kimi, DeepSeek, Anthropic, and xAI inside the app without messing up my existing settings or logins.

I want a guided setup that can detect what is already installed, keep my current Codex models, profiles, and ChatGPT login, and only migrate older supported versions safely. It should let me choose which provider to use, handle OAuth or API key sign in the right way, and keep credentials isolated so nothing gets shared between apps. I also want rollback if something goes wrong, plus a final check that confirms everything is working before I restart the app myself.

Make it work for Codex first, and if possible keep the Cursor path separate and optional. If you need anything unclear from the current docs, look up the latest info online and follow the repo’s instructions.