I used cursor extensively both at work and for personal use. Its harness is pretty darn good but I basically never used OpenAI models in it.

The first party cursor models (initially composer and now grok-cursor) and price very competitively for their quality and have very generous usage limits included in the base plans, and then per token pricing afterwards.

Occasionally I’ve used some of the Anthropic models in it but found their cost massively outweighed the benefits for the type of usage we do.

I was using Sonnet 4.5 and 4.6 for a while but the newer models are a lot more expensive at the per-token pricing.

Cursor does currently allow users to BYO OpenAI token. Given Cursor won't have access to OpenAI models for prompt engineering/evals though, there's definitely a question of whether they'd allow picking any new OpenAI models, assuming the BYOK option continues to exist at all.

It's basically not going to affect them at all. I don't know a single person that uses OpenAI models via Cursor. Saw another comment say it was 5%.