You've hit your usage limit (still after setting my key)

Hey, thanks for the request. This isn’t a bug. Using your own API keys (BYOK) in Agent and Ask modes now requires a Pro subscription on all plans, including Free.

It used to work on the Free plan as an undocumented option, but the behavior changed. More details here: Ask mode with my own API Key required Pro Subscription

Your options:

  • Upgrade to Pro ($20/month). Then you can use your Anthropic key
  • Stay on Free and use Cursor’s built-in free models (no custom keys)

I know it’s frustrating when something stops working, but this is a policy change, not a bug.