# UPID v2 manufacturing intent

UPID v2 retains the v1 geometry and document structure. The envelope and document both declare `schemaVersion: 2`. It adds two controller-neutral intent values:

- `automatic-during-positioning` for a manual rethread transition whose positioning move separates the wire;
- `after-positioning` for a stop at the destination before threading or cutting.

The host records these choices explicitly and checks exact post capabilities before generation. A post decides how to realize them. UPID carries no controller commands. Domain operations promote a v1 document to v2 when either choice is made and preserve a later supported version. Current readers accept valid v1, v2 and [v3](https://insignifi4nt.github.io/wireedm-gcode-parser/documentation/reference/docs/upid/v3/README.md) files and reject unsupported versions or mismatched envelope and document versions. Existing saved revisions retain their exact bytes, package hash and engine version.

Engine 2 compiles new saved revisions. Engine 1 snapshots remain readable through their original compilation rules and integrity hashes; generating a controller artifact from an old snapshot requires the current compiler to accept the same plan. Otherwise the user must review and save a new revision. This keeps revision history accessible without authorizing an old unsafe route.

The [v1 geometry, identity and validation rules](https://insignifi4nt.github.io/wireedm-gcode-parser/documentation/reference/docs/upid/v1/README.md#identity-and-source-of-truth) also apply to v2. Derived contour/path-element bounds must agree with their source segments, and temporary partial-cut identities cannot replace stored geometry. These correctness checks add no serialized fields or version promotion. If a previously accepted inconsistent document or colliding historical execution plan is rejected, preserve its original and review a new project/revision instead of changing installed posts or saved snapshots.

The separate saved-process simulation does not extend UPID v2: rough stock, viewing speeds, imported machine placement and release/support assumptions remain simulation settings. Playback and approximate obstruction findings do not authorize machining or represent validated machine cycle times.