Found it: the session’s saved reasoning_effort was carried over unchanged on the switch to Claude Code, and the CLI exits on a level it does not know.
This only affects sessions switched from a TopxAI model to Claude Code.
| Files | Added | Removed |
|---|---|---|
| claude_code.rs | +14 | −3 |
| claude_code_effort.rs | +4 | −1 |
Details are in the commit message.