Scheduled jobs delivering to Telegram/etc. started posting a literal
'⚠️ No reply: the model returned empty content…' message instead of
staying silent. Two interacting causes:
1. The turn-completion explainer (#34452) replaces an empty model turn
with a user-facing '⚠️ No reply…' string. In a cron context that is
not a silence marker, so the scheduler delivered it — a regression
from the previously-silent empty turn. run_job now detects the
explainer text deterministically (via the same formatter that
produced it) for abnormal-empty turn_exit_reasons and strips it to
empty, so the existing empty-response suppression + soft-fail guard
apply. The explainer is unchanged on CLI/gateway.
2. The cron suppression used a loose 'SILENT_MARKER in ...upper()'
substring check. It leaked bracketless near-markers the model emits
('SILENT', 'NO_REPLY', 'NO REPLY' — #51438, #46917) and wrongly
swallowed a real report that merely quoted '[SILENT]' mid-sentence.
Replaced with _is_cron_silence_response(): suppresses a canonical
token as the whole response, its own first/last line, or the
documented bracketed '[SILENT] <note>' prefix — while a token buried
mid-sentence in a genuine report is delivered. Preserves the
intentional cron trailing/prefix tolerance (existing tests unchanged).
Tests: bracketless-variant suppression, mid-sentence-quote delivery,
direct matcher contract, and explainer-strip + defensive real-report
delivery.