18 MAR 2026
David debugged: Caught canvas prefetch_state contradiction: failed field vs succeeded metrics
David rejected the agent's conclusion that prefetch had succeeded, demanding proof that files were actually downloaded to S3, which led to finding a contradiction between prefetch_metrics and prefetch_state fields in the DB.
David noticed the agent was reporting a contradiction without calling it out. The production logs showed prefetch_metrics with attempted=6, completed=6, failed=0, yet prefetch_state='failed' — the agent had glossed over the inconsistency.
"Prefetch succeeded. In prod, the template's prefetch_metrics show attempted=6, completed=6, failed=0. The later prefetch_state='failed' is misleading here; that field got overwritten with the downstream lecture-generation failure reason." i don't believe that. go and see what the primary files are that got prefetched and see if they were actually downloaded to s3
David's pushback forced a deeper investigation into why the same run showed conflicting state signals across two DB fields. The contradiction was traced to prefetch_state being overwritten by the lecture-generation failure rather than reflecting the actual file-download outcome.