The teacher registry drops the research tool when no search engine is
live (chat-handler's searchAvailable, 2026-09-20) — the settings row
now grays on the SAME /api/search signal, so the row and the actual
registry availability can never disagree (Teacher-stream flag,
2026-09-22, routed by master).
- researchToolUnavailable (pure): research grays exactly when the live
status says unavailable; a loading/failed fetch grays nothing; the
other tools never touch the search port.
- The row: whole-row dim (graph-view graying) + disabled toggle + the
status reason as the hint — the same line the search-engine row
under it speaks from.
Two live-caught fixes while here:
- The reason line refreshed IN the pick handler raced the section PUT
(the hint could contradict the trigger it sits under — caught with a
Brave pin: trigger 'Brave', hint still 'tavily (auto)'). The refresh
now keys on the agent prop's engine pin, so it reads post-write
state.
- The engine menu options render from a map without React keys
(console warning) — keyed.
Live-verified on 3001: no engine key → research dimmed with reason,
siblings untouched; Tavily key saved + section reopened → row alive
('search engine: tavily (auto)'); Brave pinned without its key → both
rows gray with the honest missing-key reason; Automatic restored.
Gates: typecheck, lint, 803/803, build.