Connect LM Studio via Custom

Prepare LM Studio

1. Install LM Studio and consult the local server and OpenAI-compatible API.
2. Download and load a model with tool support. Confirm the identifier provided by the server, not just the name of the downloaded file.
3. Enable the local server and check the port shown by the application. The usual setup uses localhost:1234, but your installation may differ.
4. Keep the service limited to the device; do not expose the server publicly.

Configure Browser Mate

1. Open Settings → LLM Model and select Custom (OpenAI-compatible).
2. Enter the exact identifier of the served model.
3. Fill in the full URL, for example http://localhost:1234/v1/chat/completions. Browser Mate does not append the path in Custom.
4. Fill in API key: the current runtime requires a non-empty value for Custom, even when the local server does not require authentication.
5. If you enabled authentication on the server, use the real token defined in LM Studio. If the server does not require authentication and accepts an arbitrary Bearer header, you can use a local placeholder such as lm-studio-local. That placeholder does not protect the server.
6. Save and test the connection. Start with text, then check tools and images separately.

Current extension limitation

Do not leave the key empty in Custom: the form and background validation prevents saving. If the server without authentication rejects the Bearer placeholder, this route is not verified for that configuration. Adjust authentication according to the LM Studio documentation, without weakening overall security.

Compatibility and errors

This route uses Chat Completions, tools and streaming compatible with OpenAI. A text-chat-only or Responses API is not equivalent. “Unknown capability” indicates missing information, not a successful test.

On connection errors, check the running server/model, URL, port, token and allowed origins. Do not solve CORS by exposing the service to all origins. The guide is based on the runtime and the documented interface; no call was made to your local server.