solidworks-mcp

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An MCP server that lets Claude — or any MCP client that speaks Streamable HTTP — drive SolidWorks 2021 to create engineering drawings over your LAN, through the pywin32 COM API.

Open a part, generate first-angle standard views, add dimensions and balloons, insert a BOM table, then export to PDF — all from a Claude conversation.

Features

21 tools in 5 categories:

See the full tool reference below.

Architecture

Claude Code ◄── Streamable HTTP ──► src/server.py (FastMCP)
                                         │
                                    async tool handlers
                                         │
                                    sw.execute(func)  ← asyncio + Future
                                         │
                                    COM Worker Thread (STA, singleton)
                                         │
                                    pywin32 COM → SolidWorks 2021

SolidWorks COM must be driven from a single STA thread. All tool handlers are async and dispatch their COM callables onto a dedicated worker thread, bridged back with `concurrent.futures.Future`.

Requirements

• Windows 10/11 host with SolidWorks 2021 installed
• Python 3.10+
• An MCP client that supports Streamable HTTP (e.g. Claude Code, Codex CLI, Gemini CLI, Cursor — see Compatible MCP clients) on the same trusted LAN
• Optional: a drawing template (`.drwdot`) and an SMB shared folder for large screenshots / PDFs

> Only SolidWorks 2021 has been tested. Other versions may work since the COM API is largely stable, but no guarantees.

Quick Start

1. Install (on the SolidWorks host)

git clone https://github.com/haunchen/solidworks-mcp.git
cd solidworks-mcp
python -m venv .venv
.venv\Scripts\pip install -r requirements.txt

Offline installation (host without internet access)

On a machine with internet access:

pip download -d ./wheels -r requirements.txt

Copy the repo (including `wheels/`) to the SolidWorks host, then:

.venv\Scripts\pip install --no-index --find-links wheels -r requirements.txt

2. Configure

Copy-Item .env.example .env
# edit .env — see Configuration below

3. Run

.venv\Scripts\python src\server.py

4. Connect from Claude Code (client machine)

claude mcp add --transport http solidworks http://:8080/mcp

Then just ask Claude: *"Open bracket.sldprt and create a first-angle 3-view drawing with dimensions, then export it as PDF."*

Compatible MCP clients

Any MCP client that supports Streamable HTTP and runs on your machine (or inside the LAN) can connect. Verified examples:

Agent frameworks work too: OpenAI Agents SDK (`MCPServerStreamableHttp`), LangChain (`langchain-mcp-adapters`).

> Cloud-brokered connectors cannot reach a LAN-only server: Claude Desktop / claude.ai custom connectors and the Anthropic Messages API MCP connector all connect from the vendor's cloud, which is exactly what the trusted-LAN security model blocks.

Configuration

All settings are loaded from `.env` (see `.env.example`):

Security

This server has no authentication. Anyone who can reach the port can drive your SolidWorks instance and read/write files through it.

• Deploy on a trusted LAN only — never expose the port to the internet
• Prefer binding `SW_MCP_HOST` to a specific LAN interface instead of `0.0.0.0`
• Consider OS-level firewall rules restricting access to known client IPs

Tool Reference

File operations

Drawing views

Annotation

Export

Assembly analysis

Development

# run all tests (no SolidWorks needed — the COM layer is fully mocked)
.venv\Scripts\pytest tests/ -v

Behavior contracts live in `docs/specs/` — specs with `status: active` describe the expected behavior of shipped features. Design history is in `docs/plans/`.

See CONTRIBUTING.md for development setup and PR guidelines.

License

MIT