Content
# inventor-ai
**Drive Autodesk Inventor 2026 from Claude (or any MCP client).**
A Model Context Protocol server for Autodesk Inventor's COM API. Supports parts, assemblies, work-feature constraints, exports (STL/STEP), and a `run_python` escape hatch that gives you the full Inventor object model when a dedicated tool doesn't exist yet.
> "Build me a turbocharger cartridge in Inventor" -> three parts, one fully constrained assembly, exported STL + STEP, in one prompt.
## For mech-eng / industrial-design students
If you're learning CAD and feel stuck, this repo is also a working reference for **how to drive Inventor programmatically**. The examples include a stepped pump shaft built directly from a real 2nd-year university drawing brief (`examples/imd254_shaft.py`) -- read the script and you can see exactly which COM calls produce a sketched profile, a revolve, a keyway slot, and a blind threaded hole. Open the resulting `.ipt` in Inventor and step through the feature tree to compare what you'd build by hand.
A note on academic integrity: scripts like these are study aids, not submissions. Submit your own work. The point of the brief is to learn how the part is built and dimensioned, and reading code that builds it is one way to learn that. Don't trade understanding for a shortcut.
## Why
Autodesk's first-party MCP support is for Fusion 360. Inventor users have been left out. This package fills that gap: 30+ MCP tools that cover the Inventor workflows you'd actually use day-to-day, plus an escape hatch that scales to anything else.
## Features
- **Parts**: sketches on origin planes, lines, circles, rectangles, extrude, revolve, sweep, loft, fillet, shell, mirror, circular pattern, rectangular pattern, parameters
- **Assemblies**: place components, ground, axis-mate (concentric), plane-mate (with offset, mate or flush)
- **Exports**: STL (binary or ASCII), STEP (AP203/AP214/AP242), `.ipt` / `.iam` save
- **Diagnostics**: list features, list faces, list parameters, undo, test connection
- **Escape hatch**: `run_python(code, part_name)` executes arbitrary Python with `app`, `doc`, `comp_def`, `sketch`, `tg` (transient geometry), and unit helpers pre-injected. If a feature isn't wrapped yet, you can still do it.
## Install
Requires Windows + Autodesk Inventor 2026 + Python 3.10+.
```powershell
pip install fastmcp pywin32
git clone https://github.com/dariusnaicker/inventor-ai.git
cd inventor-ai
pip install -e .
```
## Run the server
```powershell
python -m inventor_ai.server
```
Or register it with Claude Desktop / any MCP client. Add to `claude_desktop_config.json`:
```json
{
"mcpServers": {
"inventor": {
"command": "python",
"args": ["-m", "inventor_ai.server"]
}
}
}
```
Inventor 2026 must be running before you call any tool.
## Examples
Two scripts in `examples/`:
### Smoke test (40 method calls, 9 sections)
```powershell
python examples/smoke_test.py
```
Builds a 50x30x20 box, a flange with a 6-hole bolt circle, a mirrored stub, a 3x3 rectangular post array, and round-trips a parameter. Outputs to `_smoke_test_out/`.
### Turbocharger cartridge (3 parts + constrained assembly)
```powershell
python examples/turbocharger.py
```
Builds:
1. **turbo_shaft.ipt** -- 180 mm stepped shaft (revolve + fillet)
2. **turbo_bearing_housing.ipt** -- revolved housing with a 30 mm bore (lower) and a 70 mm cavity (upper) for the wheel, plus 6 bolt holes
3. **turbo_compressor_wheel.ipt** -- hub with 26 mm bore + 8 radial blades
4. **turbocharger.iam** -- fully constrained: housing grounded, shaft and wheel axis-mated to the housing's Y axis, plane-mated for axial position. 1 free DOF (shaft rotation about Y), as it should be.
Outputs to `_turbo_demo_out/`.
### IMD 254 pump shaft (real university drawing brief)
```powershell
python examples/imd254_shaft.py
```
A stepped centrifugal-pump shaft built end-to-end from the dimensions in a 2nd-year ME drawing project at Stellenbosch University. 133 mm long, six diameter steps, a 15 mm end-milled keyway, and an M4 blind threaded hole. Demonstrates that the MCP can hit real-world part complexity, not just toy demos.
Outputs to `_imd254_shaft_out/`. The original PDF brief is course material and is **not** included here.
## Tool list (30 MCP tools)
```
Connection inventor_connect, inventor_test_connection, inventor_list_open_documents,
inventor_close_document, inventor_run_python
Parts inventor_new_part, inventor_save_part, inventor_export_stl,
inventor_export_step
Sketching inventor_new_sketch, inventor_draw_line, inventor_draw_rectangle,
inventor_draw_circle
Features inventor_extrude, inventor_revolve, inventor_sweep, inventor_loft,
inventor_fillet_all_edges, inventor_shell, inventor_mirror,
inventor_circular_pattern, inventor_rectangular_pattern, inventor_undo
Diagnostics inventor_list_features, inventor_list_faces, inventor_list_parameters,
inventor_add_parameter
Assemblies inventor_new_assembly, inventor_place_component, inventor_save_assembly,
inventor_ground_component, inventor_assemble_axis_mate,
inventor_assemble_plane_mate
```
## Using `run_python` for unwrapped features
Every feature wrapper above is implemented on top of `run_python`. You can use the same escape hatch yourself:
```python
api.run_python("""
# Pre-injected: app, doc, comp_def, sketch, tg, mm_to_cm,
# EXTENT_OP, EXTENT_DIR, PLANE_INDEX, api
edges = comp_def.SurfaceBodies.Item(1).Edges
result = {"edge_count": edges.Count}
""", part_name="my_part")
```
This is how you reach Inventor's deeper API surface (work features, sheet metal, surfaces, FEM) without waiting for a dedicated wrapper. It's also a useful debugging tool when a wrapper misbehaves.
## Security
The `run_python` / `inventor_run_python` tool executes arbitrary Python on the host with live COM access. **Never expose this server beyond localhost.** FastMCP defaults to stdio transport, which is local-only. If you ever switch to HTTP/SSE transport, bind to 127.0.0.1 only and put it behind authentication. Treat the MCP server as you would a local Jupyter kernel: never trust untrusted clients.
## Contributing
PRs welcome. Areas that would help most:
- Drawing automation (`.idw` views, dimensions)
- Sheet metal features
- iLogic rule generation
- A test harness that mocks the COM layer (so CI can run without Inventor)
When adding a new feature, prefer building the wrapper on top of `run_python` (see `fillet_all_edges`, `shell`, `loft`, etc.) rather than re-implementing COM constants -- that keeps the COM surface in one place.
## Status
Beta. Tested on Inventor 2026.2 (Build 302298010). Should work on 2025+ but COM constants are version-specific so YMMV.
## License
MIT. See `LICENSE`.
