spec(cut-toolkit): eyes/hands/prove (BlenderRun)

specs/cut-toolkit/spec.md

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+# SPEC: Cut toolkit — eyes / hands / prove (BlenderRun)
+
+Status: **DRAFT**  
+Repo: `the-shit/kit`  
+Issue: [kit#16](https://github.com/the-shit/kit/issues/16)  
+Slug: `cut-toolkit`  
+Depends on: [kit#10](https://github.com/the-shit/kit/issues/10) factory-seats  
+Related: [kit#6](https://github.com/the-shit/kit/issues/6) ImageToMesh
+
+**Lie:** Kit does 3D modeling. Today Cut cannot see or touch meshes. This SPEC makes the lie true for one closed loop: see → act → measure → retry.
+
+**Seat:** Cut (smart brain configurable; Astra via OpenRouter for now). Look = honesty. Ship = PR/CI, never merge. No LLM on `/api/assign`.
+
+**Number:** LookCompare ≥ pitcher threshold on four views AND ValidateGLB green, within N turns (default 5).
+
+## Locked
+
+### Eyes
+- `RenderViews` — GLB stills for `front|side|back|ride`
+- Vision critique on those stills (no filename guessing)
+- `LookCompare` — fail ⇒ `fail`, never `visual_ok`
+
+### Hands
+- `BlenderRun` — allowlisted bpy only (load/save GLB, transform, boolean, remesh/decimate, weld, simple materials). No free shell/network.
+- `ImageToMesh` — optional blockout (kit#6 backends)
+- `MeshOps` — cheap non-bpy repairs when enough
+
+### Prove
+- `ValidateGLB` — manifold, poly budget, units, LODs
+- Turn cap with honest fail
+- Ship only after prove; hallway still `does not merge`
+
+### Brain / host
+- `KIT_CUT_MODEL` config; Look/Ship stay cheap
+- Blender on Loki (Thor borrow when idle); no cloud burst hardcoded in this SPEC
+
+## Acceptance
+- [ ] This file at `specs/cut-toolkit/spec.md` with `spec:` on kit#16
+- [ ] Fake CutLoop CI receipt (mocked tools), no GPU in CI
+- [ ] factory-seats Cut lock updated to BlenderRun allowlist after APPROVE
+- [ ] Look honesty + Ship no-merge unchanged
+- [ ] Pint + CutToolkit tests green
+
+## Non-goals
+Unreal, free bpy/shell, merge automation, multitenancy, frontier Look/Ship, TRELLIS training (kit#6).
+
+## After APPROVE
+Land tools behind flag → dogfood one asset on Loki → then attach Astra brain.