[Maxaubert]

Prism's full e2e failed "claude leaving clears the detection" three times today (core 0.41.2 and 0.41.5), passing alone. Reported by the Prism session.

Cause (a regression from #238)

• A tab's agent mark goes up on Claude's title alone; only the process poll takes it back, and the poll sends only what changed.
• fix(agent-poll): forced looks and a failing query no longer launch PowerShell nonstop (core 0.41.1) #238 spaced forced looks (5 s in main, one ask per 15 s per tab). A Claude that lived about three seconds (the test's) could come and go between two looks, so the poll's "no agent" was unchanged, never sent, and the mark stayed.
• The failing runs' terminal shows Claude did exit (^C then the PS prompt). The CSS in that TERM TAIL is xterm 6's own <style> inside .xterm, not shell input.

Fix (agentArm.ts)

• When the title stops naming an agent only the title vouched for, the poll is asked for its answer (recheck, the existing termAgentAgain path), which it sends at the next look even inside the backoff.
• MEASURED (Claude Code 2.1.301 in a ConPTY, 2026-10-16): quitting, Claude writes an empty title, then ConPTY restores powershell.exe, so a real exit always ends the title.
• The prompt (OSC 9;9) does NOT ask: a first version did, and the e2e's stand-in agents (a pwsh prompt between steps) lost their hook state (4 agentHooks/indicator checks failed). A real agent's prompt comes after its title ended anyway.
• One extra process query per such exit; nothing per frame.

Tests: a new agentArm test fails on main's code and passes (the measured exit titles); a poll test confirms an asked "no agent" is sent unchanged inside the backoff. Unit 2231 pass, typecheck clean, lint 0 errors. e2e indicator, agentHooks 43/43, agentDiag, agentKeys, backgroundWork, termReplies, paste, imagePaste, indicatorStyles all pass.

Core change: Prism gets it with the next pin. Core 0.41.5 -> 0.41.6, app 0.55.5 -> 0.55.6.

🤖 Generated with Claude Code

https://claude.ai/code/session_017XYVRPzvhLpPCr75uB6uaA