Umutcan Edizsalan
0c7f64ceb6
N1: COM hatch non-associative (AddHatch associativity=False) N2: ezdxf refuses DWG saves with clear error; server.py derives fmt from extension R19: dimension_aligned dist→distance; dimension_angular correct add_angular_dim_2l args (base/line1/line2/location) R9: polar array 360° no-duplicate (divisor=n when fill_angle%360<ε) R13: entity_offset side_x/side_y honored in ezdxf via cross-product (LINE) and distance-to-center (CIRCLE) R18: drawing_new bootstrap failure surfaces status="degraded" instead of swallowing silently Dead code: engineering/section.py, gear.generate_tooth_profile, CommandResult, _ACI_NAMES, set_layer_active, ensure_linetypes, ComBackend._batch_mode instance attr, engineering/__init__ build-seam comment Ruff: 38 auto-fixed + 5 manual → codebase is now ruff-clean; CI lint is now blocking 184 tests pass.
31 KiB
The lineweight truncation bug is confirmed devastating: ENGINEERING_LAYERS uses floats like 0.50, 0.25, 0.18, 0.13, 0.05 mm, and layer_create does int(lineweight) (ezdxf_backend.py:1034), so every one floors to 0. Counts confirmed: 109 tools, 6 resources, 5 prompts; LICENSE/benchmarks/ci.yml all absent. All load-bearing claims verified against source. I have everything needed to synthesize.
AutoCAD MCP Pro — Understanding & Research Dossier
1. Architecture at a Glance
AutoCAD MCP Pro is a single-file FastMCP 3.0 server (server.py, 2881 lines) exposing 109 @mcp.tool registrations, 6 @mcp.resource endpoints, 5 @mcp.prompt templates (verified by grep, not the docs' "87"). It uses a strategy-pattern dual backend behind one ABC (backends/base.py, ~73 abstract methods + 5 dataclasses): a live COM backend (com_backend.py, pywin32, single STA-thread ThreadPoolExecutor) and a headless ezdxf backend (ezdxf_backend.py, file-based DXF, all sync work via asyncio.to_thread under one asyncio.Lock). Backend selection (server.py::_make_backend, server.py:69): env AUTOCAD_MCP_BACKEND; Windows auto/com tries COM then falls back to ezdxf; non-Windows always ezdxf.
Request path: ErrorHandlingMiddleware → AuditMiddleware → TimingMiddleware → LoggingMiddleware (server.py:197-200) → tool fn → _backend(ctx) (server.py:207, raises ToolError if backend None) → identically-named backend method → _dc() dataclass→dict serialization (server.py:216). Lifespan (autocad_lifespan, server.py:107) builds the backend singleton into ctx.lifespan_context["backend"].
A deterministic engineering layer (engineering/ package) backs the "premium" workflow: parametric gear/keyway/titleblock primitives, a closed-enum drawing_critique, an 8-step DrawingValidator, ISO layer/linetype scaffolds, and a PlanSpec plan-before-draw contract. The central architectural fact: the premium workflow is fully implemented only on ezdxf; the COM backend stubs all 8 premium meta-tools with NotImplementedError (com_backend.py:1637-1660, verified) — yet COM is the default Windows backend.
2. Per-Subsystem Summary
server.py (transport + tool registry). Thin async wrappers over the backend singleton, grouped into 13 sections (1–12 + sub-sections 8b/8c/8d batch/template/validation + 13 premium). Owns server-side composition tools (entity_delete_many server.py:1065, layer_isolate :1216, block_find_references :1362, analysis_layer_stats :1506, entity_batch_* :1538/:1590, template_* :1695/:1730, validation_check :1749). Entry point manually parses --transport/--port/--host (server.py:2866) and refuses non-loopback HTTP unless ALLOW_REMOTE_HTTP + MCP_AUTH_TOKEN (_validate_http_bind).
backends/base.py (the contract). AutoCADBackend ABC: ~73 @abstractmethod, 2 concrete (set_layer_active, ensure_linetypes), 5 dataclasses (EntityInfo/LayerInfo/BlockInfo/DrawingInfo/CommandResult), 3 helpers (shoelace_area, deg2rad, rad2deg). Both backends define a body for every abstract method (no structural gaps); divergences are behavioral.
backends/ezdxf_backend.py (headless). Full create/modify/query/analysis/dimension/block/layer + premium meta-tools + corner ops. Transactions = full DXF snapshot to tempfile on _undo_stack (trimmed to max_undo_stack=5, O(drawing-size) per transaction_begin). View ops and system_run_command/run_lisp are documented no-ops. Screenshot/PDF via matplotlib.
backends/com_backend.py (live AutoCAD). All COM through one STA worker with per-call timeout (com_call_timeout, default 60s) and executor-rebuild on timeout/fatal HRESULT. Corner ops via _safe_send_command (CMDACTIVE-polling). Win32 PrintWindow screenshots. 8 premium meta-tools + block_create_from_entities are stubs.
engineering/ (deterministic CAD). gear.py (involute spur/helical outlines), keyway.py (DIN 6885), titleblock.py (ISO 7200 A3), layers.py (mech/pid/iso13567 sets), critique.py (6 focuses), validator.py (8-step gate), plan_spec.py (PlanSpec/Issue + ISO-128 lineweight set). section.py (cutting_plane_line, apply_section_hatch) and gear.generate_tooth_profile are dead code (exported, zero callers/tests).
tests/ (184 functions, 14 files). One ezdxf-only backend fixture (conftest.py). COM backend, server→sanitizer wiring, and section.py have zero coverage.
3. Complete MCP Tool Inventory (grouped; ✅ real / ⚠️ partial / ❌ stub-or-missing)
All 109 tools are registered in
server.pyand have real ezdxf implementations. "Status" below reflects the COM backend (the Windows default) plus correctness caveats. Nothing is purely aspirational/unregistered.
| § | Tools | ezdxf | COM | Notes |
|---|---|---|---|---|
| 1 Drawing (12, doc says 11) | info, new, open, save, save_as, export_dxf, export_pdf, purge, audit, close, undo, redo | ✅ (redo ❌ no-op ezdxf_backend.py:487) | ✅ | drawing_redo inert on ezdxf; header says 11 but 12 registered (drawing_redo server.py:426) |
| 2 Entity Create (13) | line, circle, arc, polyline, rectangle(→polyline), text, mtext, hatch, spline, ellipse, point, block_ref | ✅ | ✅ | mtext has no rotation param on ezdxf (:578); hatch pattern-only single loop |
| 3 Dimensions (5) | linear, aligned, angular, radius, diameter | ⚠️ aligned/angular xfail (tests/test_dimensions.py:16); angular ignores tx/ty + fixed dist=10 (ezdxf:705) | ✅ | No dimstyle/tolerance support either backend |
| 4 Modify (14) | move, copy, rotate, scale, mirror, offset, trim, extend, fillet, chamfer, delete, array_rectangular, array_polar, set_properties | ⚠️ offset ignores side (:868); corner ops LINE+LINE only (:1535-1750); polar 360° dup (:946) | ⚠️ offset ignores side (:860); corner ops via SendCommand | |
| 5 Query (3) | entity_get, entity_list, entity_delete_many | ✅ | ✅ | COM entity_list = O(n) per-item COM reads (:967) |
| 6 Layer (14) | list, create, delete, set_current, modify, freeze, thaw, lock, unlock, hide, show, isolate, linetype_list, linetype_load | ⚠️ lineweight int() truncation (:1034) | ✅ | See RISK-2 |
| 7 Block (7) | list, insert, explode, get_attributes, set_attributes, create_from_entities, find_references | ✅ | ⚠️ create_from_entities ❌ stub (:1253) | BlockInfo.description never populated |
| 8 Analysis (8) | stats, find_in_region, measure_distance, measure_area, bounding_box, select_by_layer, select_by_type, layer_stats | ⚠️ region fallback insert/start only (:1330) | ✅ | hand-rolled loops vs ezdxf query/groupby |
| 8b Batch (2) | entity_batch_create, entity_batch_modify | ✅ | ✅ | |
| 8c Template (2) | template_apply_layers, template_list | ✅ | ✅ | Duplicates _LAYER_TEMPLATES/prompt layer sets |
| 8d Validation (1) | validation_check | ✅ | ✅ | |
| 9 View (4, doc says 5) | zoom_extents, zoom_window, screenshot, zoom_and_screenshot | ⚠️ zoom = no-op (:1394) | ✅ | Header says 5 |
| 10 Transactions (3) | begin, commit, rollback | ✅ (commit file-I/O outside lock :1452) | ⚠️ flag-leak on error (:1402) | |
| 11 System (6) | status, get_variable, set_variable, run_command, run_lisp, about | ⚠️ run_command/lisp no-op | ⚠️ run_lisp result always 'nil' (:1487); about catalog drifted | |
| 12 Engineering (7) | gear_draw_helical/spur/section_aa, keyway_draw_keyed_bore/section, titleblock_apply_iso_a3, drawing_finalize | ✅ | ✅ (use generic entity_create_*) | Validator/titleblock import-guarded → None risk |
| 13 Premium (8) | drawing_plan, drawing_critique, point_from_snap, construction_xline, construction_clear, drawing_apply_iso_layers, dimension_auto, entity_select_smart | ✅ | ❌ all NotImplementedError (:1637-1660) | The documented-mandatory workflow is dead on COM |
Documented-but-missing entirely: none. Documented-as-working but stubbed on default backend: the 8 premium tools (§13) + block_create_from_entities on COM.
4. Cross-Cutting RISK Register (merged, deduped, severity-sorted)
| # | Sev | Risk | Location | Evidence |
|---|---|---|---|---|
| R1 | CRITICAL | All 8 premium meta-tools raise NotImplementedError on COM (the Windows default). The "non-negotiable for production" workflow (drawing_plan→apply_iso_layers→critique→finalize) 500s on the primary platform. |
com_backend.py:1637-1660 | Verified verbatim; ezdxf impls real (ezdxf_backend.py:1753-2050) |
| R2 | CRITICAL | layer_create does int(lineweight) so every sub-1.0 ISO mm value (0.50/0.25/0.18/0.13/0.05) floors to 0. The entire ISO-128 lineweight discipline is silently nulled; drawing_apply_iso_layers/drawing_new bootstrap produce flat 0-weight layers. |
ezdxf_backend.py:1034; values engineering/layers.py:16-26 | Both verified. ezdxf wants integer hundredths (50=0.50mm), not raw mm |
| R3 | HIGH | _check_iso128 is a permanent no-op: lw <= 0: continue (critique.py:50) skips every layer made 0 by R2. The advertised ISO gate can never fire. Comment "the layer dataclass already normalises to mm" (critique.py:53) is false (ezdxf_backend.py:189 stores raw float(lw)). |
engineering/critique.py:37-64 | Verified verbatim |
| R4 | HIGH | _check_dim_overlap reads properties['text_position'/'defpoint'/'insertion_point'], but the ezdxf DIM extractor sets only dim_type (ezdxf_backend.py:166-168) → dim_points always empty → check is a silent no-op. |
engineering/critique.py:194-197 | — |
| R5 | HIGH | COM timeout path (stuck.shutdown(wait=False)) cannot kill the STA worker still blocked in SendCommand → permanently leaks one CoInitialize'd thread + COM proxy per timeout; no CoUninitialize anywhere. |
com_backend.py:415-433, 68-71 | — |
| R6 | HIGH | Zero COM-backend test coverage (~80 methods incl. UndoMark transactions, SendCommand corner ops, CMDACTIVE guard). Passing ezdxf transaction tests give false confidence for the semantically different COM model. | tests/ (no ComBackend import); conftest.py:8-15 | — |
| R7 | HIGH | Server→sanitizer wiring untested: test_security.py tests sanitize_command/lisp/validate_path in isolation; no integration test proves system_run_command/lisp actually call them. A refactor dropping the call (server.py:2035/2052) passes all security tests while raw commands reach SendCommand. |
server.py:2035,2052; tests/test_security.py | — |
| R8 | HIGH | LISP-aliasing bypass ((setq f command)(f "ERASE")) is claimed-defended in a comment (security.py:138-140) but has no adversarial test; UNC/~/symlink path escapes in validate_path also untested. |
security.py:138-179; test_security.py:177-231 | — |
| R9 | MED | entity_array_polar full-360° fill double-places: step=radians(360)/(count-1) puts the last copy at 0°==original → duplicate. Hits the common bolt-circle/gear pattern the engineering layer relies on. |
ezdxf_backend.py:946-947 | — |
| R10 | MED | drawing_finalize calls drawing_save_as(str(validated)) with no fmt. ezdxf default fmt='dxf' (ezdxf:345) vs COM fmt='dwg' (com:515) vs save_as tool default 'dwg' (server:336) → 3-way inconsistency; format backend-dependent, not path-derived. |
server.py:2299 | Verified (omits fmt) |
| R11 | MED | drawing_save_as(fmt='dwg') on ezdxf writes DXF bytes to a .dwg path and returns {'format':'dwg'} — silent wrong-format file. ezdxf cannot write DWG; should error or use odafc. |
ezdxf_backend.py:345-352 | — |
| R12 | MED | dimension_angular ignores tx/ty, fixed distance=10.0 → arc radius wrong for large/small parts; breaks COM parity. |
ezdxf_backend.py:705-722 | — |
| R13 | MED | entity_offset ignores side_x/side_y (both backends); only distance sign flips side; ARC/LWPOLYLINE/ELLIPSE raise "not supported". |
ezdxf:868-908; com:860-874 | — |
| R14 | MED | Engineering titleblock/validator symbols import-guarded to None (engineering/__init__.py:40-51); if module truly fails to import, tools raise opaque "NoneType not callable" instead of clear ToolError. |
server.py:2266,2294 | — |
| R15 | MED | system_about static tool_groups catalog drifted: omits all 15 engineering+premium tools, misfiles entity_delete_many. Agents inspecting capabilities can't see the CLAUDE.md-mandated tools. |
server.py:2070-2106 | — |
| R16 | MED | COM transaction_active left stale-True if commit/rollback _run raises; rollback issues EndUndoMark+UNDO B SendCommand without the CMDACTIVE guard used elsewhere → can interleave mid-command. |
com_backend.py:1402,1411-1421 | — |
| R17 | MED | _safe_send_command busy-polls CMDACTIVE with time.sleep(0.05) on the single STA thread → monopolizes the executor up to deadline; deadline_s(8s) decoupled from _run timeout(60s). |
com_backend.py:1521-1536 | — |
| R18 | MED | drawing_new swallows bootstrap failures into result['bootstrap']={'error':...} and reports success → un-bootstrapped drawing looks normal though CLAUDE.md treats the scaffold as a precondition for gear_/titleblock_. |
server.py:280-294 | — |
| R19 | MED | dimension_aligned/dimension_angular permanently xfail(strict=False) — advertised tools shipped broken; an accidental fix wouldn't alert. |
tests/test_dimensions.py:16-27 | — |
| R20 | LOW | _registered_tool_count reaches into FastMCP privates (mcp._local_provider._components, 'tool:' prefix); a minor upgrade → tool_count=-1 surfaced to clients. |
server.py:231-234 | — |
| R21 | LOW | Involute flank prepends a straight radial root→base segment (no trochoid fillet) → geometrically wrong dedendum for root_r<base_r; root-arc gap when root_r>=base_r; degenerate arc for teeth≤2. |
engineering/gear.py:40-50,163-190 | — |
| R22 | LOW | drawing_undo/transaction_rollback share one _undo_stack with no transaction-id/depth separation; reload doesn't reset _doc_path/_current_layer. |
ezdxf_backend.py:470-484,1462-1476 | — |
| R23 | LOW | COM system_run_lisp always reports result='nil' (SendCommand returns None); no CMDACTIVE guard → a prompting LISP form deadlocks next call. |
com_backend.py:1487-1492 | — |
| R24 | LOW | _apply_attrs sets entity.dxf.linetype without _ensure_linetype_loaded (unlike set_properties/layer_modify) → linetype='HIDDEN' on create may render Continuous or raise on save. |
ezdxf_backend.py:491-501 | — |
| R25 | LOW | block_find_references calls entity_list(type_filter='INSERT') with no limit (bypasses max_list_limit) → unbounded INSERTs into memory; assumes every backend populates properties['block_name']. |
server.py:1362-1370 | — |
| R26 | LOW | View zoom ops unconditionally registered but no-op on ezdxf → success response implies the view changed when it didn't; view_zoom_and_screenshot may not frame the requested region on ezdxf. |
server.py:1814-1831,1870 | — |
| R27 | LOW | validator.py title check substring-matches 'SPUR'/'HELICAL SPUR' on TEXT layer → false-positive blocks drawing_finalize if any note contains 'SPUR'. |
engineering/validator.py:166-181 | — |
| R28 | LOW | COM _find_autocad_hwnd grabs first visible window whose title contains 'AutoCAD' → may capture palette/splash/About dialog; not tied to AcadApplication.HWND. |
com_backend.py:283-300 | — |
| R29 | LOW | Broad except Exception: pass swallows COM faults (disconnected/busy) at debug level in ~20 sites → bypasses the HRESULT reconnect logic in _run. |
com_backend.py:199,244,868,901,1216,… | — |
5. Doc-vs-Code Drift Table
| Claim (source) | Reality | Verdict |
|---|---|---|
| "87 tools" (CLAUDE.md, README:6) | 109 @mcp.tool (verified) |
STALE (soft — both add "count is dynamic" caveat) |
| "104 tests" (README:83) | 184 test functions across 14 files (verified) | STALE (~80 under) |
| Section 1 "(11 tools)" (CLAUDE.md) | 12 (drawing_redo server.py:426) |
WRONG |
| Section 9 "(5 tools)" (CLAUDE.md) | 4 view tools registered | WRONG |
| "12-section taxonomy" (CLAUDE.md) | 1–12 + 8b/8c/8d + 13 = 6 extra groups | INCOMPLETE |
| Premium workflow "non-negotiable for production" (CLAUDE.md) | 8/8 premium tools dead on COM (default Windows backend) | OVERCLAIM |
| "MIT — see LICENSE" (README:409) | No LICENSE file (verified absent) | DEAD LINK / legal drift |
benchmarks/ referenced (README:39,302,367) |
Absent (verified) | DEAD LINK (forward-looking) |
| ".github/workflows/ci.yml" + "GitHub Actions CI" (README:84,358) | git status D; absent on disk (verified) |
CI REMOVED while docs claim it |
"Premium discipline lives in .claude/skills/autocad-mcp-premium/" (CLAUDE.md) |
Entire tree git-deleted (28 deletions) + all .cursor/ deleted |
DANGLING POINTER |
| README tests/ tree (README:347-355) | Omits 6 of 14 test files + engineering/ package | STALE |
system_about tool_groups |
Omits 15 engineering+premium tools | DRIFT |
BlockInfo.description field (base.py:71) |
Never populated by either backend | DEAD FIELD |
| critique.py:53 "normalises to mm" comment | Stores raw DXF lineweight (ezdxf:189) | FALSE COMMENT |
engineering/__init__.py:37-39 "Agent B … in flight"; com_backend "Task #7/#8/#9" |
Multi-agent build seams shipped unreconciled | TODO-IN-PROD |
| Dockerfile, .env.example (README) | Present (verified) | OK |
6. Test Coverage Gaps (ranked)
- COM backend: 0% coverage (com_backend.py entire file) — transactions (UndoMark vs ezdxf snapshot are different semantics), SendCommand corner ops, CMDACTIVE guard, timeout/HRESULT recovery, all 8 premium stubs. Highest-risk untested surface; it's the production path. (R6)
- Server→sanitizer integration — no test proves tools invoke
sanitize_command/lisp/validate_path. (R7) - Sanitizer adversarial cases — LISP aliasing, command word-boundary evasion (
.ERASE), UNC/~/symlink path escapes — the comment claims defenses with no tests. (R8) - Critique detection paths —
iso128,layer_color,dim_overlaponly exercised on a clean drawing (assert they don't fire); their actual detection logic and the unknown-focus branch (critique.py:241) are never proven. (R3, R4) dimension_autoordinate (ezdxf:1988) untested; chain/baseline covered.dimension_aligned/angularpermanently xfail — shipped broken. (R19)- Uncovered backend methods (both backends):
system_get/set_variable,system_status,drawing_close,drawing_export_pdf,entity_create_block_ref,block_set_attributes,linetype_list/load(load-bearing for bootstrap),view_zoom_*,view_screenshot. engineering/section.py(dead code) — 0 coverage.- Transaction nesting/error semantics — only single begin→commit/rollback tested; nested, rollback-without-begin, layer/block restoration untested.
- Infrastructure: CI workflow deleted (no PR gate);
pytest-covdeclared but no--cov/fail-under; several "template/validation" tests assert nothing about the named feature (vacuousif start:guards, test_batch_template.py:30-34).
7. Research Synthesis
7a. Academic techniques (2025–2026) that validate or upgrade this design
- GeoGramBench (ICLR 2026, arxiv.org/abs/2505.17653): frontier LLMs score <50% at high-abstraction Program-to-Geometry. → Empirically justifies the repo's no-coordinate-guessing rule and
point_from_snap/entity_select_smart. Action: expand the deterministic geometry surface (point_intersection,point_offset,point_along) so the LLM never computes coordinates. - Self-Improving CAD w/ FEA feedback (arxiv.org/html/2605.17448v2): deterministic controller owns validation, LLM owns design; +13.4pp per feedback round; frontier models get zero first-attempt strict passes — iteration beats more tokens. → This is the repo's architecture, but
drawing_critiqueis one-shot. Action: make it a routed repair loop;Issue(plan_spec.py:64-81) already carries severity/handles/detail — add per-finding repair hints. - CADSmith (arxiv.org/abs/2603.26512): 5-agent Planner/Coder/Executor/Validator/Refiner, dual loop, exact-kernel measurements + independent VLM judge → Chamfer 28.37mm→0.74mm (38×), IoU 0.81→0.96; removing the rendered image alone made hard cases 35× worse. → The repo renders a screenshot at finalize (server.py:2301-2309) but only checks bytes exist (validator step 7). Highest-leverage single upgrade: feed that render to a VLM judge + add an automated Refiner.
- CADFusion (ICML 2025, arxiv.org/abs/2501.19054) & Seek-CAD (arxiv.org/abs/2505.17702): render is a first-class signal; step-wise visual feedback catches errors mid-build. → Add a
visualcritique focus; run critique per construction step using the existing transaction model. - ProCAD "Clarify Before You Draw" (arxiv.org/html/2602.03045v1): one-round clarification → invalidity 14.6%→0.9%, Chamfer ~80% lower. →
drawing_planrecords intent passively; add a pre-plan ambiguity/conflict detector that returns targeted questions before anyentity_create_*. - FutureCAD (arxiv.org/abs/2603.11831): NL → exact B-Rep primitive grounding fixes the fillet/chamfer "which primitive" problem. → Directly targets the repo's hardest API: trim/extend/fillet/chamfer need exact handles plus keep_x/keep_y. NL grounding ("fillet the top-left corner") removes the burden GeoGramBench shows LLMs fail at.
- Text-to-CadQuery (2505.06507), CAD-Coder (2505.14646), EvoCAD (2510.11631): field converged on Python/CadQuery macros; open local VLMs read CAD images reliably; candidate-generate + critique-as-fitness raises first-try quality. → Add more parametric meta-tools (the gear/keyway pattern) and/or a sandboxed parametric-script tool; an open VLM (CAD-Coder, Florence-2 for GD&T, arxiv.org/abs/2411.03707) keeps the visual tier off frontier APIs.
- MUSE (arxiv.org/html/2605.28579) + CadBench (2605.10873): grade manufacturability/functionality, not just shape; standard metrics = volumetric/surface IoU, Chamfer, Invalidity Ratio. → Replace
validator.py's regex/title heuristics with a staged code→geometric→rubric-judge protocol; emit a single scalar "drawing score" for regression tests (the repo has no quantitative quality metric).
7b. Competitive landscape
| Product | 3D | Render-critique loop | Validation gate | HTTP auth | Code escape hatch |
|---|---|---|---|---|---|
| AutoCAD MCP Pro | ❌ 2D only | ⚠️ finalize-only, symbolic | ✅ unique (critique+validator+ISO) | ❌ none | ⚠️ COM-only run_command/lisp |
| build123d-mcp/agentcad (github.com/pzfreo/build123d-mcp) | ✅ | ✅ in-loop | ❌ | — | ✅ |
| FreeCAD Robust MCP (150+ tools) | ✅ + FEM | ⚠️ | ❌ | — | ✅ |
| Blender MCP (~22k★) | ✅ | ✅ | ❌ | — | ✅ Python exec |
| RhinoMCP | ✅ | ✅ viewport | ❌ | — | ✅ |
| Fusion360/Onshape MCP | ✅ parametric | — | ❌ | ✅ OAuth/keys | — |
Snyk's 9-CAD-MCP roundup (snyk.io/articles/9-mcp-servers-for-computer-aided-drafting-cad-with-ai/): vision only in FreeCAD/Blender/Rhino; design validation in none; HTTP auth only in Onshape/Fusion. → Our moat is the design-rule validation gate; the field beat us on 3D, in-loop render-critique, and auth. Autodesk's own in-AutoCAD assistant demo (aecmag.com/features/autodesk-shows-its-ai-hand/) flagship = automated compliance checking — exactly our niche, so we must make standards compliance the sharpest, most-cited capability. Adam/Zoo (techcrunch.com/2025/10/31/...) set the UX bar: parametric editability + post-gen dimension sliders + entity-level conversational editing.
7c. Under-used COM / ezdxf API + ISO standards
COM (ActiveX) gaps (every create call hits ModelSpace, com_backend.py:125-127):
- PaperSpace/Layouts + Plot config —
drawing_export_pdf(com_backend.py:528-534) calls barePlot.PlotToFile(path,'DWG To PDF.pc3')with no page setup → ignores the A3/scaledrawing_planpromised. Addlayout_*/viewport_*(AddPViewport, StandardScale, CanonicalMediaName). (help.autodesk.com ActiveX ref) - AddTable (BOM/revision tables), AddMLeader (ISO leader notes — CLAUDE.md reserves "leader notes" but no tool creates them), Fields (auto-updating title block), GetDynamicBlockProperties (parametric symbol libraries —
block_insertonly does attribute text, com:1195-1251), DimStyles.Add+CopyFrom (no ISO-129 dimstyle is ever set → undercuts the "Dimensions are ISO 129" rule), named UCS (per-view frames forview_count), AttachExternalReference (shared borders), gradient/island hatch. - 3D solids/regions/booleans —
system_statusadvertisesall_entity_types(com:1443) which is false; either implementsolid_*or correct the claim. - Push selection into AutoCAD:
entity_list(com:967) andanalysis_select_by_type(com:1352) loop ModelSpace.Item(i) in Python (O(n) COM round-trips — the #1 perf killer);analysis_select_by_layer(com:1339) already shows the rightSelectionSet.SelectAllgroup-code-filter pattern to copy.
ezdxf gaps (Grep confirms zero use of set_gradient/set_solid_fill/paperspace/add_viewport/odafc/export_dwg/groupby/dimstyles/MTextEditor/add_ordinate/qsave):
addons.odafc.export_dwg= real DWG (R12–R2018) → fixes R11/R10 (drawing_save_as fake DWG). (ezdxf.mozman.at/docs/addons/odafc.html)- drawing-addon
Configuration(lineweight_policy ABSOLUTE, background_policy, SVGBackend/PyMuPdfBackend) → true ISO lineweights + vector output, replacing raw matplotlib (ezdxf:357-379,1400-1424). query()mini-language +groupby()→ replace hand-rolled loops in analysis_stats/select/entity_select_smart (which pulls 5000 entities then filters in memory, ezdxf:2008-2050).recover.readfile+Auditor.fix→ real repair;drawing_audit(ezdxf:448) reports but never fixes;drawing_open(ezdxf:309) has no recover fallback.MTextEditor(stacked tolerance fractions), Hatch gradients/islands/edge-paths, DimStyle overrides (no ISO dimstyle today, ezdxf:668-774), path-module offset (generalizes LINE/CIRCLE-only offset + LINE-only corner ops).
ISO standards conformance:
- ✅ ISO 128-2 lineweight set encoded (plan_spec.py:85, verified) — but nulled by R2 and group-vs-element-class not checked.
- ⚠️ ISO 7200 title block — A3-only hardcoded (titleblock.py:16-17), informal labels ("DWG NO" vs ISO field names), len×0.3 centering heuristic (titleblock.py:171), missing "Document type"/"Date of issue".
- ❌ ISO 129-1 dimensioning — biggest functional gap:
dimension_*(base.py:226-257) have no param for ±/limit/fit (H7/g6) tolerances or text override → toleranced production dims impossible. (iso.org/obp/ui/#iso:std:iso:129) - ❌ ISO 1101 / ASME Y14.5 GD&T — entirely absent (grep-confirmed): no feature control frame, datum, or ISO 2768 general-tolerance note. (gdandtbasics.com/iso-vs-asme-standards/)
- ⚠️ ISO 13567 — static mech-only starter list (layers.py:51-62), no field-grammar parser/validator.
8. "What Would Make This the BEST AutoCAD MCP" — Prioritized Thesis
The evidence converges: the repo is architecturally ahead on dual-backend + standards-validation but behind on the closed-loop, the production-output plumbing, and the very workflow it markets. Priorities, evidence-backed:
P0 — Make the marketed product actually work on its default platform.
- Implement the 8 premium meta-tools on COM (R1, com_backend.py:1637-1660). Today the CLAUDE.md-mandatory workflow 500s on every Windows install. Nothing else matters until this ships.
- Fix the lineweight
int()truncation (R2, ezdxf_backend.py:1034 → multiply mm by 100 / map to ACAD enum). This single bug nullifies the ISO-128 system and makes the iso128 critique a permanent no-op (R3). The standards-validation gate is the competitive moat (Snyk roundup; Autodesk's own flagship demo) — it must be real. - Add CI + a coverage gate + the first COM smoke tests (R6, ci.yml deleted; pytest-cov unconfigured). Restore the LICENSE file (legal drift).
P1 — Own the moat by closing the loop (the #1 accuracy lever in every 2025–26 paper).
4. Turn drawing_critique into a routed iterative Refiner loop with per-Issue repair hints and a bounded budget (CADSmith Refiner; FEA-agent +13.4pp/round; Physics-in-the-Loop 3.3–6.0 iters converge). The Issue dataclass already carries handles+detail.
5. Promote the finalize screenshot to a first-class visual critique focus fed to a VLM judge (CADSmith: dropping the render → 35× worse; CADFusion). Use an open local VLM (CAD-Coder / Florence-2 for GD&T) behind a [vision] extra so the headless path is unaffected. Add a dimension round-trip check (VLM-read dims vs created dimension_* entities) to catch what proximity-only dim_overlap (R4) cannot.
6. Add a ProCAD-style pre-plan clarification pass to drawing_plan (invalidity 14.6%→0.9%): detect missing/conflicting dims, material, tolerance, view_count-vs-intent before any geometry.
7. Emit a scalar "drawing score" / Invalidity-Ratio (MUSE/CadBench) so the premium workflow is regression-testable — the repo has no quantitative accuracy metric.
P2 — Reach production-drawing parity (what un-toleranced ISO 128 can't deliver).
8. ISO 129 tolerances + ISO 1101/Y14.5 GD&T: add ±/limit/fit params to dimension_* and a gd_frame(symbol, tol, datums, modifiers) + datum/ISO-2768-note primitive. This is the categorical gap blocking real part drawings; no surveyed text-to-CAD product covers 2D GD&T — a differentiator.
9. Real plotted sheets: COM Layout/PaperSpace/Plot-config so drawing_plan(sheet_size, scale) and titleblock_apply_iso_a3 produce a correct A-series plot; on ezdxf wire odafc.export_dwg (kills the fake-DWG R11) and the drawing-addon Configuration for true-lineweight SVG/PDF.
10. An ISO-129 DimStyle created once and applied to all dims (COM DimStyles.Add+CopyFrom; ezdxf dimstyle overrides) so "Dimensions are ISO 129" becomes true, and MLEADER for the leader notes the docs already reserve.
P3 — Catch the field on breadth (table-stakes elsewhere, absent here).
11. A 3D solids tier (extrude/revolve from 2D profiles + booleans on COM; STEP/STL on ezdxf) — or correct the false all_entity_types claim (com:1443). Every competitor has 3D.
12. Parametric editability + entity-level conversational editing (Adam/Zoo): capture driving dims in PlanSpec, expose a re-drive tool; "select this circle → make it the 20mm bore" via existing handle model + entity_select_smart/point_from_snap.
13. Authenticated remote HTTP (API-key middleware) given dangerous_commands_enabled exists (server.py:111); a standard-parts/symbol library (library_insert over block_insert, dynamic-block props); NL→B-Rep grounding (FutureCAD) over the brittle trim/fillet/chamfer keep-point API.
P4 — Hygiene that compounds with the above. Generalize LINE-only corner ops + LINE/CIRCLE-only offset via the ezdxf path module; replace hand-rolled selection with query()/groupby() (ezdxf) and SelectionSet.SelectAll filters (COM); fix entity_array_polar 360° dup (R9), dimension_angular tx/ty (R12), the COM thread-leak CoUninitialize (R5); delete dead section.py/generate_tooth_profile; reconcile system_about catalog (R15) and the stale README/CLAUDE.md drift (§5).
Files central to every priority: backends/com_backend.py:1637-1660 (P0.1), backends/ezdxf_backend.py:1034 + engineering/layers.py:14-26 (P0.2), engineering/critique.py:37-64,194-197 (P0.2/P1.5), engineering/plan_spec.py:64-87 (P1.4/P1.6/P2.8), backends/base.py:226-257 (P2.8), server.py:528-534/2294-2309 (P2.9).