# Part Native Routing And Continuation Efficiency

Subsequent completion: `PART_BUILDER_DOCUMENT_PROGRESS.md` records the native
six-mode Builder, mounted task, transaction/persistence behavior and passing
business acceptance. The Builder limitations below are historical. Chamfer
and BoxSelection remain separate pending workflows.

2026-09-16. This repairs an actual native call path; it does not certify the
complete Builder, Chamfer or Check Geometry desktop workflows. Keep all 1508
requirements and all 1342 missing executable-coverage items.

## Repaired Behavior

The `part.pythonFamilyBatch` desktop branch for `Part_Builder`, `Part_Chamfer`
and `Part_CheckGeometry` now calls the existing `executePartDesktopCommand`
OCCT implementation. It previously returned a command description, including
a constant geometry-validity claim, instead of executing the operation.

The real output includes serialized BREP, validity, volume and edge count.
It explicitly declares `resultScope=native-geometry` and
`documentChanged=false`; geometry execution does not pretend to create a
persistent document feature. The mounted Part adapter recognizes this actual
native result shape with structural validation. Metadata-only replies remain
rejected. The family facade retains native error codes and messages rather
than replacing them with an unrelated protocol diagnostic.

Only `FreeCADWebPartBoxProbe` was incrementally rebuilt. The existing frontend
build passed its geometry-boundary check, TypeScript and Vite build, and
synchronized public/preview artifacts. No IFC runtime or IFC cases were rebuilt
or rerun. Current IFC semantic acceptance remains valid.

## Evidence

`part-native-route-diagnostics/2026-09-16T02-57-39-540Z/result.json` records
10 passing checks using one WASM load and one adapter compilation: two Builder
shapes with independently measured area, self-intersection rejection, real
edge chamfering, checking its output, corrupt BREP rejection, document-selection
validation and rejection of legacy placeholder replies.

`business-evidence/d530c34d605d7404c989d048-20260916T030257758136.json` retains
the updated Builder diagnostic through the business runner. Native planar
geometry assertions pass, including area 100, but the whole requirement stays
`not_implemented` because document/task/browser semantics are incomplete.
Execution took 2.011 seconds. A matching `--reuse` request took 0.138 seconds,
executed zero cases and preserved the same incomplete evidence.

## Avoiding Repeated Stalls

The supplemental source reader previously stopped after four distinct windows,
even with a known native repair anchor. Continuous development now permits 16
distinct windows within 48 KB total, preserving exact-file restrictions,
per-window bounds, locking and duplicate suppression. The legacy profile keeps
its four-window limit. Three focused tests cover these properties.

Builder batches now include the actual local desktop implementation and UI
sources, `TaskShapeBuilder.cpp`, `.h` and `.ui`, in their permitted support
paths. A new turn need not rediscover or be denied those files.

Child build environments default `FREECAD_WEB_FAST_LINK=ON`, using the existing
incremental public-asset plugin; explicit OFF is retained. The full frontend
build observed in this turn spent 97.9 of 100 seconds preparing/copying output.
This motivates enabling the existing fast path, not inventing another cache.
Existing asset tests verify unchanged file reuse, changed-file replacement,
obsolete-file removal and path guards. No unmeasured speedup is claimed.
Scheduler regression suite: 180 passed; the context suite, including the new
ON/OFF environment check, passed all 12 tests after the follow-up change.

## Next Implementation

Do not repeat the repaired metadata-routing investigation or unchanged Builder
diagnostic. The next work is native document and task behavior:

- `TaskShapeBuilder.cpp` implements six modes: edge from vertices, wire from
  edges, face from vertices, face from edges, shell from faces, solid from shell.
  It uses real Part APIs, native selection/subelements, a new Part::Feature and
  a transaction for each Create action. Closing the task is not shape creation.
- Reuse the current document owner and the existing document/FCStd mechanisms;
  do not invent a replacement document or treat a BREP result as persistence.
- Preserve cross-document rejection, error rollback, undo/redo and independent
  documents. Add mounted controls and real browser/native cases before placing
  these command IDs in coveredIds or accepting them.
- Chamfer still needs persistent features/current document operands and its
  task lifecycle. BoxSelection still needs actual rectangle/camera picking and
  native face selection. Existing raw geometry handlers are reusable inputs.

All progress counts come from generated evidence audits. Passing this routing
diagnostic does not close any of those full workflow requirements.