Re-cut a Reel at a new pause threshold: the source never changes

Instagram says everything First Draft does is reversible (read 2026-10-09). In the API the same safety comes from a rule: video trim, audio detach and Timeline all write new files and leave the source untouched. Keep the source artifact and a JSON cut list, and trying a stricter or looser pause threshold costs one $0.10 Timeline render per try, with the speech-to-text pass paid once.

What to store so any cut can be rebuilt

A cut is fully described by four things. Store them next to the project and you can regenerate or discard any version.

• The source media.sume.com URL, never overwritten by a Sume job.
• The STT words[] from one video_inspect run (billed at the STT rate, $0.01 per audio minute).
• The detached wav URL from one POST /v1/audio-detach ($0.01).
• The parameters you chose: gap threshold, floor (0.2 s) and any padding. The ranges follow from them.

What each try costs

Assumptions: the Reel stays under 60 s, so each render bills one minute at $0.10, and you use Timeline alone rather than trim jobs. The $0.02 up front is the one STT minute plus the one detach.

Compare versions before paying for them

POST /v1/timeline-1.0/plan is unbilled. Post each candidate document and read duration_seconds, segment_count and billable_minutes; keep the threshold whose length you like, then render only that one. The plan does not download media, so it will not show padded-source warnings.

Limits

• A render is a new job, so use a new Idempotency-Key per threshold; reusing a key with a different body returns 409 idempotency_conflict.
• Sume does not keep a hidden edit history of your cut. The reversibility is the unchanged source plus your own saved cut list.
• Plan is for Timeline only; trim jobs have no unbilled preflight.