Hey, this isn’t a bug. It’s the current behavior for custom OpenAI-compatible models.
For models that aren’t in Cursor’s catalog, Cursor sets the context window to 1M by default. Cursor can’t auto-detect the real context window from your provider. You might see 200K if the model name matches something in Cursor’s catalog, or if a different default kicks in. The exact trigger isn’t documented.
Workaround: register your custom model under a unique name that doesn’t match any model in Cursor’s catalog. Then it’ll use the 1M default.
Right now there’s no way to set the context window manually. This is tracked as a feature request, you can follow it here: Unlock Full Context Window with Own API Keys
I also explained the 1M default logic in more detail here: Custom Models Set The Context Window to 1M