Where does the bug appear (feature/product)?
Cursor CLI
Describe the Bug
When cursor-agent cli receives a prompt request, if the DNS lookup of the cursor endpoint fails, instead of issuing a clear “failed to resolve endpoint of ap2.cursor.sh blah” it instead gives the misleading error:
Warning: The provided API key is invalid.
The API key was loaded from the CURSOR_API_KEY environment variable.
Please check you have the right key, create a new one, or authenticate without it.
This seems to imply successful communication with the endpoint, and positive invalidation of the api key value, when in reality, it did zero https requests.
This can cause a lot of sadness and mispent time debugging the entirely incorrect thing.
Solution would be to catch DNS resolution errors and in general, all HTTPS communication errors and raise those relevant issues up as errors rather than what is a non-sequitur.
$ ~/.local/bin/cursor-agent -v
2026.01.28-fd13201
Steps to Reproduce
In my case, I was running it in a container without proper dns resolution.
Expected Behavior
A clear error that correctly signals difficulty in communicating with the endpoint, and the relevant step that failed.
Operating System
Linux
Version Information
2026.01.28-fd13201
Does this stop you from using Cursor
Yes - Cursor is unusable