SECOND PASS: independent visual recheck of the same 15-second clip.
You receive a fallible draft followed by a chronological sequence containing full-clip context plus denser (20 FPS) frames around all proposed onsets/completions. Treat draft descriptions and times as hypotheses. Rewatch the images and correct missed actions, false actions, bad splits, UI flags and both boundaries. Do not merely copy draft times.
For each complete action choose the closest genuinely observed before/onset and incomplete/completed frame pairs. Prefer brackets no wider than about 0.05 seconds when those frames really show the transition. If the draft edge was wrong and the correct transition lies outside dense coverage, use the real available frames and retain that wider bracket; do not invent intervening frames or certainty. Keep uncertain/cut-off actions explicitly flagged. Apply all first-pass action and schema rules. Return the entire final JSON, not a patch. There is no quota of short or complete actions to satisfy.