How to use a Claude Subscription in Cursor without paying for API tokens

In Cursor, you can connect any LLM via API that is compatible with the OpenAI request format. This means you can connect Claude via API and pay for tokens. However, if you have a Claude subscription, you can only use it in Claude Code. There, the request format is Anthropic, which differs from OpenAI. You cannot take your Claude subscription and add it to Cursor because the request formats are incompatible. You cannot make requests to the Claude API using a Claude subscription. There are already solutions on GitHub that proxy requests from Cursor to Claude using the subscription without paying for API tokens. They convert the OpenAI format to Anthropic and back. But to add this to Cursor, it's not enough to simply run the process on localhost and add the URL to Cursor, because Cursor first sends requests to its own backend, and from there to the OpenAI-compatible API. If you add localhost there, their backend simply won't be able to reach it. That's why you need to set up a tunnel, and