Cron agents use the exact final response `[SILENT]` as a delivery-suppression
sentinel. If a wake relay accidentally POSTs that sentinel to `/api/chat/start`
and 8701 restarts while the turn is pending, session repair materializes it as
a visible `{role: user, _recovered: true}` message. The pending value can then
be recovered again on later restarts, creating repeated `[SILENT]` turns.
Treat the exact normalized sentinel as a successful no-op at both server-side
turn entry points: the HTTP `/api/chat/start` handler and
`start_session_turn`. Both checks run before session lookup, runtime barriers,
or pending-state mutation. Matching is deliberately exact and case-sensitive,
so `[silent]`, prose containing `[SILENT]`, and ordinary user text are not
suppressed.
Add regression tests proving both paths return HTTP/status 200 without session
lookup, plus negative cases for non-exact text. The new tests fail 3/3 before
the fix. Targeted and neighbouring chat-start suites pass 21/21.
Co-authored-by: allenliang2022 <allenliang2022@users.noreply.github.com>
Co-authored-by: nesquena-hermes <nesquena+hermes@gmail.com>
