A 6-hour freshness window proves only that some scan ran recently, which a
manual mid-day scan satisfies. Scenario: a manual scan succeeds at 13:00;
the 15:30 near-close pipeline's scan step is disabled or fails; at 15:30
the 13:00 completion is still 'fresh', so the shadow step trades that
earlier batch despite no successful scan in the current pipeline.
_run_pipeline now records its start in a per-task contextvar, visible to
the steps it awaits. run_shadow_book reads it and requires the scan
completion marker to be at/after the pipeline start, so a scan that failed
or was disabled in this pass (marker left at a prior run, before the
pipeline began) cannot be substituted by an earlier manual scan. A direct
Admin trigger has no pipeline context and falls back to the freshness
window -- an explicit operator action, not an automated one.
Tests pin the reported case: a fresh manual scan predating the pipeline
start is refused; the pipeline's own post-start scan is accepted.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
dennisthiessenandClaude Fable 5
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