Cursor custom API configuration and compatibility check

Cursor's setting API and custom API capabilities will vary with versions, packages, and model providers. According to the official description, custom API Key is mainly used for standard chat models; some special functions may still use Cursor's own model. First confirm that the current version indeed provides the corresponding provider or Base URL entry before configuring.

Quick conclusion

The Cursor displaying "API Key Valid" only means that the authentication check may pass, but it does not mean that the Agent, model mapping, and tool calls all use this API. After configuration, you must check the final domain name, path, and model ID from the request log, and then test the normal chat and Agent tasks separately.

Check before you start

1. Call with curl /v1/models, confirm that the Key is valid.
2. Copy the real model ID without using the web display name.
3. Confirm whether the target provider or custom Base URL entry exists in the current version of Cursor; if the interface does not have this option, do not copy the old version of the tutorial.

Configuration steps

Look for options related to API Keys, OpenAI API Key, or Base URL in Cursor's model or API settings. Different versions may display differently, and custom Key does not mean that all Agent functions will use this API.

Recommended parameters:

API Key: you are here AICreated by Quick Station Key
Base URL: https://www.aifast.club/v1
Model: YOUR_MODEL_ID

After filling in, send a short message that can be accurately verified:

Reply only：CURSOR_API_OK

Check that the response contains exactly the expected text and check the final address with the response from the request log model field. Don’t judge a model’s identity based on what it says about itself in the text. After the short request is successful, test reading files, modifying code, and long context tasks.

Determine whether to append repeatedly /v1

If the Cursor log shows:

https://www.aifast.club/v1/v1/chat/completions

Change the Base URL to:

https://www.aifast.club

Whether to retain /v1 It depends on whether the current client automatically appends the path, and the actual request log shall prevail.

FAQ

API Key Valid, but conversation failed

"Key verification successful" only indicates that the authentication may be passed, but does not mean that the current model name, request protocol and functional mode are compatible. Continue to view the status code and response body of the specific request.

model not found

• The model ID is spelled exactly the same.
• Whether the model supports the current API type.
• Whether the client replaces custom model names with built-in aliases.

Agent mode failed, normal chat succeeded

Agent patterns may rely on tool calls, long context, or specific response fields. Verify the normal chat first, and then confirm whether the selected model supports tool calls. Don't judge that all functions are compatible just based on the success of the text conversation.

Next step

Create a separate API Key for Cursor to facilitate usage statistics and permission revocation. When it comes to private repositories, don't send sensitive source code to unevaluated models or services.

If you are currently using a community protocol conversion project instead of the Cursor official custom Key, please read this first Cursor2API common error reports, risk checks and standard API migration, differentiate between upstream entry changes, conversion layer issues, and client capability boundaries before migrating.