- Confirmation reply is sent (`Thinking level set to high.` / `Thinking disabled.`). If the level is invalid (e.g. `/thinking big`), the command is rejected with a hint and the session state is left unchanged.
- **Pi/Tau**: injects `--thinking <level>` (skipped for `off`).
- **Claude & other text agents**: appends the cue word to the prompt text as above.
## Heartbeats
- Heartbeat probe body is `HEARTBEAT /think:high`, so it always asks for max thinking on the probe. Inline directive wins; session/global defaults are used only when no directive is present.