Hey, thanks for the report with all the details.
This is a known issue with the serialization error on Windows. The team is already working on a fix. Similar reports:
- Serialization error
- Cursor Agent gets stuck in “Connection failed” loop after PowerShell output-truncation pipeline; local protobuf serialization fails (invalid int 32: 4294967295)
The root cause is an int32 overflow while serializing terminal output or exit codes. It can show up as a connection error, but it isn’t actually a network issue.
Workaround: When the error happens:
- Start a new chat
Cmd/Ctrl+T/N - Or restart Cursor
Let me know if the workaround helps.