jhonny-editor/code/docs/uxp-slip-workflows.md

Guarded track-item slips through stable UXP

slip_track_item_uxp adds the documented source-only operation that maps to a timeline slip: it offsets one audio or video item’s source in and out points without moving that item’s sequence start or end.

Authority and API boundary

The implementation is a stable Premiere UXP 25.6+ composition of AudioClipTrackItem/VideoClipTrackItem timing getters, createSetInPointAction, createSetOutPointAction, Project.lockedAccess, and Project.executeTransaction. It does not use CEP, QE, raw evaluation, UI automation, or a native SDK.

Guarded flow

1. Call action: "inspect" with a bounded media type, track index, and clip index. The result includes the active project and sequence IDs, coordinates, timeline start/end/duration, source in/out/duration, speed, and reverse state.
2. Call action: "apply" with that complete snapshot, confirm_slip: true, a non-zero slip_by_seconds between -60 and 60, and a required operation_id.
3. The bridge serializes slips per project/sequence/track-item coordinate. It rereads the full target after entering that tail, rejects any stale field, then adds exactly the source-in and source-out actions to one transaction.
4. It resolves the target by coordinate again and verifies its project, sequence, coordinates, timeline start/end/duration, source duration, speed, reverse state, and exact shifted source points.

Only forward 1x items whose source and timeline durations agree are supported. The command rejects a negative source in point and any requested source time outside the documented 0–86,400 second bound. Premiere does not expose a documented source-handle maximum through this target, so an out-point beyond available media can still be rejected or normalized by the host; the final readback then fails rather than claiming success.

Proof boundary

Automated tests exercise the schema, stale checks, same-operation replay, one-transaction composition, and deterministic different-operation-ID serialization. They are mocked/static proof only. No licensed Premiere host has validated the operation, its rendered frames, A/V link synchronization, persistence after reopening, or Undo behavior. A readback failure can occur after the host transaction commits; inspect the target before another edit.