---
verdict: pass
remediation_round: 0
---

# Milestone Validation: M001

## Success Criteria Checklist
## Success Criteria Checklist

The M001 roadmap defines success via per-slice "After this" demo criteria (no separate success criteria section). Each is evaluated below:

### S01: "POST /engine/trace with a PNG logo returns valid SVG using both Potrace and VTracer modes"
- [x] **PASS** — `POST /engine/trace` endpoint exists in `engine/api/routes.py`. S01 summary confirms 14 integration tests covering both Potrace and VTracer modes. S01-UAT test case 7 verifies the response shape contract. 76 tests pass including mode-specific tests (`TestTraceEndpointPotrace`, `TestTraceEndpointVtracer`). Full test suite re-run confirms 196 tests pass (S01 tests still green).

### S02: "/engine/trace returns valid DXF and JSON output; /engine/simplify reduces node count on complex SVG"
- [x] **PASS** — `output_format` parameter routing confirmed in routes.py (svg/dxf/json). DXF generator (`engine/output/dxf.py`) produces AC1015 DXF with LWPOLYLINE entities. JSON generator (`engine/output/json_output.py`) outputs structured path arrays. `/engine/simplify` endpoint confirmed in routes.py. 35 API integration tests cover all format combinations for both endpoints. S02-UAT defines test cases for DXF binary response with X-Kerf-Metadata header, JSON path structure, and simplification node reduction.

### S03: "GET /engine/presets returns all presets; each preset produces distinct output from same input; engine runs in Docker"
- [x] **PASS** — `GET /engine/presets` endpoint confirmed in routes.py. All 5 preset JSON files verified on disk (sign, patch, stencil, detailed, custom) with correct structure (preprocessing/vectorization/postprocessing sections). 28 preset-specific tests include cross-preset output differentiation tests. `docker/Dockerfile.engine` implements multi-stage build with HEALTHCHECK. S03 summary confirms container builds, starts healthy, and serves all endpoints.

## Slice Delivery Audit
## Slice Delivery Audit

| Slice | Claimed Deliverable | Delivered? | Evidence |
|-------|-------------------|-----------|----------|
| S01 | FastAPI server with /engine/trace, OpenCV preprocessing, Potrace + VTracer vectorization | ✅ Yes | `engine/main.py`, `engine/api/routes.py` (POST /engine/trace), `engine/pipeline/preprocessing.py` (OpenCV pipeline), `engine/pipeline/vectorize.py` (potrace_trace + vtracer_trace). 76 tests passing. |
| S01 | 76 tests | ✅ Yes | All included in 196-test suite; original S01 tests still pass. |
| S02 | postprocess_svg() with RDP simplification, island detection, node counting | ✅ Yes | `engine/pipeline/postprocess.py` (414 lines) with PathInfo objects, RDP, island detection via signed-area. |
| S02 | Output generators: DXF, JSON, SVG | ✅ Yes | `engine/output/dxf.py` (66 lines, ezdxf AC1015), `engine/output/json_output.py` (76 lines), `engine/output/svg.py` (22 lines). |
| S02 | /engine/simplify endpoint | ✅ Yes | Confirmed in routes.py — POST /engine/simplify with epsilon + output_format params. |
| S02 | output_format routing on /engine/trace | ✅ Yes | Confirmed in routes.py — accepts svg/dxf/json. |
| S02 | 169 tests | ✅ Yes | All included in 196-test suite. |
| S03 | 5 presets (sign, patch, stencil, detailed, custom) | ✅ Yes | All 5 JSON files present in `engine/presets/` with correct structure verified. |
| S03 | Preset loader with param merge/resolution | ✅ Yes | `engine/presets/loader.py` with resolve_params() — user overrides preset defaults. |
| S03 | GET /engine/presets endpoint | ✅ Yes | Confirmed in routes.py. |
| S03 | Docker image with healthcheck | ✅ Yes | `docker/Dockerfile.engine` — multi-stage build, HEALTHCHECK pings /engine/health. |
| S03 | GET /engine/health endpoint | ✅ Yes | Confirmed in routes.py. |
| S03 | 196 total tests | ✅ Yes | Full suite run: `196 passed, 21 warnings in 0.96s`. |

## Cross-Slice Integration
## Cross-Slice Integration

### S01 → S02 Boundary
- **Contract:** S01 produces raw SVG strings from potrace_trace() and vtracer_trace(). S02 consumes these via postprocess_svg().
- **Status:** ✅ Aligned. S02 summary confirms postprocess_svg() replaced the old regex metadata extraction (D003). PostProcessResult is the universal intermediate representation. 169 tests pass including integration tests that exercise the full S01→S02 pipeline path.
- **Response shape evolution:** S01 defined `{output, format, metadata: {path_count, node_count_total, open_paths, warnings, processing_ms}}`. S02 extended metadata to include `island_count`. This is additive — backward compatible.

### S02 → S03 Boundary
- **Contract:** S03 consumes the post-processing pipeline and output format generators. Presets configure the full pipeline (preprocessing + vectorization + postprocessing params).
- **Status:** ✅ Aligned. S03 summary confirms resolve_params() merges preset defaults with user overrides. Presets contain preprocessing, vectorization, and postprocessing sections that feed directly into the pipeline stages built in S01/S02. 28 preset integration tests validate end-to-end preset→pipeline→output flow.

### Cross-cutting: routes.py
- The API router (routes.py) was modified by all three slices. Final state (7364 bytes) contains all endpoints from all slices: /engine/health, /engine/presets, /engine/trace, /engine/simplify. No regressions — 196 tests confirm all endpoints work together.

### No boundary mismatches detected.

## Requirement Coverage
## Requirement Coverage

No formal requirements (REQUIREMENTS.md) were defined for this milestone. The project uses decision records (D001–D004) and per-slice success criteria as the governing specification.

**Decision compliance check:**
- **D001** (Engine/App separation): ✅ Docker image copies only engine source — no App code. Engine is a standalone HTTP API with no App dependencies.
- **D002** (Build order): ✅ M001 builds Engine first as specified. App canvas (M002) and Export/Deploy (M003) are deferred.
- **D003** (Post-processing replaces regex): ✅ Superseded as documented. postprocess_svg() provides structured PathInfo objects.
- **D004** (Multi-stage Docker build): ✅ Implemented exactly as specified — builder compiles pypotrace, runtime uses slim image with only runtime libs.

No unaddressed requirements exist.

## Verdict Rationale
**Verdict: PASS**

All three slices delivered exactly what the roadmap specified:

1. **S01** — Core pipeline with preprocessing + dual vectorization modes (Potrace/VTracer) via POST /engine/trace. 76 tests established the foundation.

2. **S02** — Full post-processing (RDP simplification, island detection, open path repair) with three output format generators (SVG, DXF, JSON). /engine/simplify endpoint added. Test suite grew to 169.

3. **S03** — 5 tuned presets with merge-based param resolution, GET /engine/presets endpoint, and multi-stage Docker image with healthcheck. Final test suite: 196 tests, all passing in under 1 second.

**Evidence is strong:**
- 196 tests pass (verified by live test run, 0.96s, exit 0)
- All source files exist on disk with expected structure
- All 4 API endpoints confirmed in routes.py
- All 5 preset configs verified with correct JSON structure
- Dockerfile exists with multi-stage build and HEALTHCHECK
- Cross-slice integration points align — no boundary mismatches
- All 4 architectural decisions (D001–D004) are satisfied
- UAT artifacts exist for all 3 slices with comprehensive test cases

No gaps, regressions, or missing deliverables found. The milestone is ready for completion.
