SolidWorks MCP Server

A comprehensive Model Context Protocol (MCP) server that gives Claude (or any MCP-compatible LLM client) full control of SolidWorks through the COM API. 187 tools spanning every major workflow — modeling, sketching, assemblies, drawings, sheet metal, weldments, mold tools, surfaces, simulation, motion, rendering, materials, and more.

✅ Verified on SolidWorks 2024 — handles SW 2024’s dual property/method API quirks (DISPID invocation, property-get bypass, 23-arg FeatureExtrusion3, VARIANT marshaling, etc.). Should also work on SW 2018+.

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✨ What you can ask Claude to do

• “Create a 100×60×40 mm aluminum part, render it, and export to STEP”
• “Open this assembly, check for interferences, then mass-analyze each component”
• “Generate a 3-view drawing of bracket.sldprt with dimensions, GD&T, and a BOM, then save as PDF”
• “Design a parametric sheet-metal enclosure with 2 mm thickness, four edge flanges, and export flat patterns”
• “Build a weldment frame from 40×40×4 square tube along this sketch”
• “Set up a static simulation, apply this fixture and 500 N load, and run the analysis”

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📋 Prerequisites

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🚀 Installation

1. Clone the repository

git clone https://github.com/Eduardof0nt/Solidworks-MCP-Server.git
cd Solidworks-MCP-Server

2. Install Python dependencies

pip install -r requirements.txt

If you hit permission issues installing globally, use a virtual environment or --user:

python -m venv .venv
.venv\Scripts\activate
pip install -r requirements.txt

3. Verify the server starts

python server.py

The server will sit waiting for MCP stdio traffic — that’s correct. Hit Ctrl+C to stop; you’ll wire it into a client in the next step.

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🔌 Configuring an MCP client

Claude Desktop

Edit %APPDATA%\Claude\claude_desktop_config.json (create it if it doesn’t exist):

{
  "mcpServers": {
    "solidworks": {
      "command": "python",
      "args": ["C:\\full\\path\\to\\Solidworks-MCP-Server\\server.py"]
    }
  }
}

⚠️ Replace C:\\full\\path\\to\\Solidworks-MCP-Server\\server.py with the absolute path on your machine. Use double-backslashes (\\) in JSON.

Restart Claude Desktop. The solidworks server should appear in the MCP indicator (bottom-right “🔌” icon).

Claude Code (CLI)

claude mcp add solidworks -- python "C:\full\path\to\Solidworks-MCP-Server\server.py"

Or edit ~/.claude.json (or your project’s .mcp.json) and add the same mcpServers block as above.

Other MCP clients

The server speaks stdio MCP. Any MCP-compatible client can connect by spawning python server.py as a subprocess.

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▶️ First run

1. Start SolidWorks (the server can auto-launch it, but starting it manually is faster).
2. Open your MCP client (Claude Desktop, Claude Code, etc.).
3. Ask Claude: “Connect to SolidWorks and check the status.”

Claude should call sw_connect and sw_get_status, returning the SolidWorks version and any open documents.

Tools Reference

Connection

Files & Documents

Selection

Sketch

Features (Part)

Reference Geometry

Surface Modeling

Assembly

Drawing

Dimensions & Parameters

Analysis

Properties & Configurations

Equations

Visualization

Macros & Automation

Sheet Metal — Basic

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Extended Toolset (additional 99 tools)

Materials & Appearance

Body Operations

Curves & 3D Sketch

Advanced Sketch

Surface Modeling Extended

Sheet Metal — Complete

Weldments

Mold Tools

Drawing — Extended

Assembly — Extended

Display & Visualization

Motion & Simulation

Global Variables & Parametrics

Display States & Sensors

File Management Extended

Advanced Features

Export Extended

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Example Workflows

Create a Simple Box

1. sw_create_part()
2. sw_create_sketch(plane='Front Plane')
3. sw_sketch_rectangle(x1=0, y1=0, x2=100, y2=60)
4. sw_exit_sketch()
5. sw_extrude(depth=40)
6. sw_save_document(file_path='C:/parts/box.sldprt')

Parametric Cylinder

1. sw_create_part()
2. sw_create_sketch(plane='Front Plane')
3. sw_sketch_circle(cx=0, cy=0, radius=25)
4. sw_exit_sketch()
5. sw_extrude(depth=100)
6. sw_add_equation('"Height" = 100mm')
7. sw_add_equation('"D1@Boss-Extrude1" = "Height"')

Assembly with Mates

1. sw_create_assembly()
2. sw_insert_component(file_path='C:/parts/base.sldprt', fixed=True)
3. sw_insert_component(file_path='C:/parts/shaft.sldprt', z=50)
4. sw_add_mate(mate_type='CONCENTRIC', entity1='Face@shaft-1', entity2='Face@base-1')
5. sw_add_mate(mate_type='COINCIDENT', entity1='Face@shaft-1', entity2='Face@base-1')

Sheet Metal Bracket (with bend)

1. sw_create_part()
2. sw_create_sketch(plane='Top Plane')
3. sw_sketch_rectangle(x1=0, y1=0, x2=200, y2=100)
4. sw_exit_sketch()
5. sw_base_flange(thickness=2.0, bend_radius=1.5)
6. sw_create_sketch(plane='')
7. sw_sketch_line(...)  # bend line
8. sw_exit_sketch()
9. sw_sketched_bend(angle=90)
10. sw_flatten_sheet_metal()
11. sw_export_flat_pattern('C:/parts/bracket_flat.dxf')

Aluminum Part with Custom Color and Mass Analysis

1. sw_create_part()
2. sw_create_sketch('Front Plane')
3. sw_sketch_circle(0, 0, 25)
4. sw_exit_sketch()
5. sw_extrude(depth=100)
6. sw_set_material('Aluminum 6061-T6')
7. sw_set_appearance_color(r=180, g=180, b=200, transparency=0.0)
8. sw_get_mass_properties()  # returns mass, volume, COG

Drawing with Multiple Views + GD&T

1. sw_create_drawing()
2. sw_add_drawing_view(view_type='front', x=100, y=200, scale=1.0)
3. sw_add_projected_view(parent_view_name='Drawing View1', direction='right')
4. sw_add_detail_view(x=80, y=150, radius=15, scale=2.0, label='A')
5. sw_add_centerline(view_name='Drawing View1')
6. sw_add_geometric_tolerance(gtol_text='Position 0.1 A B C', x=50, y=80)
7. sw_add_surface_finish(symbol_type='machining', roughness='3.2')
8. sw_add_bom_table()
9. sw_export_drawing_pdf('C:/drawings/part.pdf')

Parametric Design with Global Variables

1. sw_create_part()
2. sw_set_global_variable(name='Width', value=100)
3. sw_set_global_variable(name='Height', value=60)
4. sw_create_sketch('Front Plane')
5. sw_sketch_rectangle(0, 0, 100, 60)
6. sw_exit_sketch()
7. sw_extrude(depth=40)
8. sw_link_dimension_to_equation(dim_name='D1@Sketch1', expr='"Width"')
9. sw_link_dimension_to_equation(dim_name='D2@Sketch1', expr='"Height"')
# Now changing "Width" or "Height" globals drives the geometry

📝 Notes & Conventions

• All length inputs are in millimeters (mm). The server converts internally to meters for the SolidWorks COM API.
• All angles are in degrees (converted to radians internally).
• SolidWorks must be open (or the server will auto-launch it via sw_connect).
• Entity names must match exactly as shown in the SolidWorks FeatureManager tree (case-sensitive).
• The server runs as a stdio MCP server (single client, local only — no network exposure).
• All COM calls are routed through a single STA thread to satisfy SolidWorks’ threading model.

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🏗️ Architecture

┌──────────────────┐      stdio       ┌──────────────────┐    COM API    ┌──────────────┐
│  Claude / MCP    │ ◀──────────────▶ │   server.py      │ ◀───────────▶ │  SolidWorks  │
│     client       │   JSON-RPC       │   (FastMCP)      │   (win32com)  │   (running)  │
└──────────────────┘                  └──────────────────┘               └──────────────┘
                                              │
                                              ▼
                                      ┌──────────────┐
                                      │ sw_client.py │
                                      │ COM wrapper  │
                                      │ (STA thread) │
                                      └──────────────┘

• server.py — FastMCP stdio server. Defines all 187 sw_* tools with Pydantic input validation.
• sw_client.py — Synchronous SolidWorksClient class wrapping SolidWorks COM. Includes:
  • _get(obj, name) helper for SW 2024’s dual property/method getters
  • _invoke(obj, dispid, *args) for DISPID-based method dispatch (bypasses win32com’s property-get confusion)
  • VARIANT(VT_DISPATCH, None) callout helpers for SelectByID2-style calls
• All COM operations are queued onto a single-threaded ThreadPoolExecutor initialized with pythoncom.CoInitialize.

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🛠️ Troubleshooting

“SolidWorks is not running” / sw_connect fails

• Make sure SolidWorks itself is installed and licensed.
• Try launching SolidWorks manually first, then call sw_connect.
• If COM isn’t registered: open SolidWorks once as Administrator, then close.

pywintypes.com_error: (-2147352571, 'Type mismatch.', ...)

• An argument has the wrong type. Most common cause: passing None where COM expects an interface pointer. This server already wraps null callouts with VARIANT(VT_DISPATCH, None) — if you see this in a new tool, copy that pattern.

'str' object is not callable or 'int' object is not callable

• A SolidWorks getter is being exposed as a property in your SW version. Use _get(obj, 'MethodName') instead of obj.MethodName(). See sw_client.py for examples.

FeatureExtrusion3 — Parameter not optional

• Your SolidWorks version expects a different parameter count. sw_extrude already falls back through 23/22/20-param signatures.

Claude doesn’t see the solidworks server

• Confirm the path in claude_desktop_config.json is absolute and uses \\ escaping.
• Confirm python is on PATH (try python --version from a fresh terminal).
• Check Claude Desktop logs: %APPDATA%\Claude\logs\mcp*.log.

“SolidWorks COM error” on first tool call

• The first call after launch can be slow (SolidWorks initializing). Retry after a few seconds.
• If persistent, restart SolidWorks and your MCP client.

ERROR: another SolidWorks MCP server instance is already running

The server enforces a single-instance lock (Windows named mutex Local\SolidWorksMCPServer_SingleInstance_v1) because multiple processes fighting over the same SolidWorks COM connection causes every tool call to hang.

• If both Claude Desktop and Claude Code try to launch the server, only the first succeeds — the second client will see no solidworks tools.
• To fix: fully close whichever client you don’t need (system tray → Quit for Claude Desktop, or close all CLI sessions). The mutex auto-releases when the holding process exits.
• To bypass for debugging only, set SW_MCP_ALLOW_MULTIPLE=1 in the spawning environment.

SolidWorks GUI never appears (processes alive but no window)

If Get-Process SLDWORKS shows running processes with MainWindowHandle: 0, those are zombies from an interrupted launch — typically after a force-kill (Stop-Process -Force) during startup. They will never finish initializing and are not registered in the COM Running Object Table.

• Fix: Get-Process SLDWORKS,sldworks_fs | Stop-Process -Force to kill them, then launch SolidWorks fresh from the Start menu and wait for the main window before calling any sw_* tool.

pip install permission denied

• Use pip install --user -r requirements.txt or create a virtualenv.

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🤝 Contributing

Contributions welcome — there’s plenty of surface area in SolidWorks’ COM API. Some ideas:

• Add tools for missing categories (SimulationXpress, Toolbox, PDM, Route, Electrical)
• Improve error messages with SW-specific context
• Add unit tests for tools that don’t require a live SolidWorks instance
• Document additional SolidWorks-version-specific quirks you find

To contribute:

1. Fork the repo and create a feature branch.
2. Follow the existing tool pattern: client method in sw_client.py + Pydantic input model + @mcp.tool wrapper in server.py.
3. For methods you’ve actually run against SolidWorks, note the SW version in the docstring.
4. Open a pull request with a description of the change and which SW version you tested on.

If you find a SW version quirk that needs handling (different DISPID, different param count, property vs. method), please document it in the PR — that’s the most valuable kind of contribution for this project.

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⚠️ Limitations

• Windows only. SolidWorks COM is not available on macOS/Linux.
• Single MCP client at a time (stdio transport).
• Long-running operations block. Simulations and large rebuilds will tie up the COM thread.
• SolidWorks UI must remain interactive for some operations (file dialogs, error prompts). This server uses swSaveSilent and equivalent flags to suppress dialogs where the API allows.
• Add-in dependent tools (sw_create_simulation_study, sw_take_photoview_screenshot) require the corresponding add-in to be installed and loaded.

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📄 License

Released under the MIT License. SolidWorks® is a registered trademark of Dassault Systèmes SolidWorks Corporation; this project is not affiliated with or endorsed by Dassault Systèmes.

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🔗 Related Projects

• Model Context Protocol — the open protocol this server implements.
• SolidWorks API documentation
• pywin32 — Python COM bindings used under the hood.