I have a Pro Cursor subscription and today my employer offered me a company API key for Anthropic models. It is unclear to me now, how does it work, because I want to keep my subscription and use the auto mode for lighter tasks and for heavier ones the Claude models, but I got a notification after turning on my own API key “With your Cursor Pro subscription, you do not need to use your own Anthropic key”.
So my questions are :
if I switch to Claude models after Anthropic API key activation, will Cursor “pull” the quota from my included subscription API limit, or from the API key?
Does this limit somehow the usage of Cursor? Because I’ve got some notification, that several functions cannot be billed to an API key, like agent, tab. So I am now confused a bit.
Where do requests go if the Anthropic key is enabled?
If your key is enabled and you explicitly pick a claude-* model in Chat or Composer, the request goes through your Anthropic key and Anthropic bills it directly based on their pricing, not from your Pro subscription quota.
Important: Auto mode doesn’t work via BYOK. It routes requests through Cursor’s built-in models, and that traffic is covered by your subscription, not your key. If you want a request to go to Anthropic, you need to manually select a specific Claude model.
What about Tab, Apply, Agent?
These features use Cursor’s custom and fine-tuned models, and they can’t be billed to an API key. They always run through the Pro subscription. The warning is about that. It’s not a limitation caused by your key, it’s how those features work, they can’t be proxied through Anthropic.
Bottom line: Pro is still useful even if you bring your own key. It covers Tab, Apply, Agent, Auto mode, and non-Claude models. Your Anthropic key helps save subscription quota when you explicitly choose Claude. The banner you do not need to use your own Anthropic key is just informational.