Beat sync

Speed, cuts and transitions land on the same instants, and the instants come from measurement.

Workflow

1. Measure. agentWorkspace action audio_inspect on the music clip returns the beat grid (bpm, beatOffset, beatTimes, downbeatTimes), tempo and energy changes. If no beat evidence is available, do not invent a grid and do not claim beat sync; cut on the action instead.
2. Convert to timeline time. Inspection timings are window-relative: add the window's from and the clip's timeline start.
3. Lay the grid: addMarkers with those timeline times, then ONE sliceClip with times on them (timeline seconds strictly inside the clip). Or retime existing clips with snapToBeat (bpm and beatOffset from the analysis; group mode keeps staggered graphics together; dryRun:true first).
4. Emphasis, not every beat. Land emphasis cuts on downbeats and respect 4, 8 and 16 bar phrases. Cutting on literally every beat for a minute is a metronome.
5. Transitions ON the beat, never between: one style ("zoom-blur", "whip-pan", "glitch" or "flash", 0.15 to 0.3 s) repeated. A different transition each time reads as a template demo.
6. Speed as rhythm: ramp into a hit with one setKeyframeTrack speed curve (speed-ramps). Punctuate the biggest hit only (applyCameraShake or a punchIn).
7. Land the last cut on the final beat; a velocity edit that trails off feels unfinished.

Gotchas