The shared recent-line tail is measured from the bottom of the screen, so a long todo list plus the composer and a multi-line status line can push the live spinner row past the 24-line limit, and a working Claude session reads as idle via the idle-composer rule. Claude's rules are all region-anchored (live status from the last logical rows above the composer, blockers from around the prompt, chrome from the bottom lines), so the bounded tail adds no false-positive protection there. Make the detector tail per-agent: Claude consumes the full active screen, while the whole-text legacy detectors keep the bounded tail as their guard against transcript history. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>