CAD MCP Server

An MCP server that lets Claude (and any other MCP client) read, analyze, and edit CAD files — both DXF and DWG — powered by ezdxf.

It runs as a small local Python process over stdio. Your CAD files never leave your machine.

• DXF — read and edit directly, no extra setup.
• DWG — Autodesk's proprietary binary format. ezdxf cannot parse it alone, so DWG is converted to DXF automatically via the free ODA File Converter (one-time install). Once installed, DWG works everywhere DXF does.

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Quick start (easiest — no clone, no pip)

If you have uv installed, you don't clone anything or manage dependencies — uvx fetches and runs the server for you.

Install uv once:

# Windows (PowerShell):
powershell -c "irm https://astral.sh/uv/install.ps1 | iex"
# macOS / Linux:
curl -LsSf https://astral.sh/uv/install.sh | sh

Then add the server in one line:

# Claude Code:
claude mcp add cad -- uvx --from git+https://github.com/Codemod3/cad-mcp cad-mcp

For Claude Desktop, drop this into your config (see paths below) — no clone, no paths to edit:

{
  "mcpServers": {
    "cad": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/Codemod3/cad-mcp", "cad-mcp"]
    }
  }
}

That's it. First run downloads deps automatically; later runs are instant. Restart the client and the tools appear. (DWG still needs the free ODA File Converter; DXF works immediately.)

Prefer to clone and manage Python yourself? See Manual install.

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What it can do

Read / analyze (never modifies files)

Tool	What it does
dxf_summary	Overview — version, units, layers, entity counts, extents
dxf_list_layers	All layers with color, linetype, on/frozen/locked state
dxf_get_layer_entities	All entities on a specific layer
dxf_get_entities_by_type	Filter by type (LINE, CIRCLE, TEXT, …), optional layer filter
dxf_get_text	Extract all TEXT and MTEXT annotations
dxf_get_dimensions	Extract all DIMENSION annotations
dxf_get_blocks	List named block definitions
dxf_get_block_detail	Inspect entities inside a block

Edit (writes to a copy — your original is never touched)

Tool	What it does
cad_create_editable_copy	Copy the original DXF/DWG to <name>_edited.dxf. Run this first.
cad_add_line	Draw a line
cad_add_circle	Draw a circle
cad_add_arc	Draw an arc
cad_add_text	Add a text label
cad_add_polyline	Draw connected segments (LWPOLYLINE), optionally closed
cad_add_layer	Create a layer
cad_delete_entity	Delete one entity by its handle
cad_export_dwg	Convert the edited .dxf back to .dwg (needs ODA File Converter)

Editing model — safe by design:

1. Call cad_create_editable_copy on your original → it returns the copy's path.
2. Pass that copy path to every edit tool. Edits save in place and stack, so keep drawing on the same file.
3. Your original is never modified.
4. DWG can't be written directly, so edits always happen on the .dxf copy; run cad_export_dwg at the end if you need a .dwg back.

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Requirements

• Python 3.10+ (only for the manual install; uvx handles this for you)
• The Python packages in requirements.txt (installed below)
• DWG only: the free ODA File Converter

Check your Python:

python --version      # must be 3.10 or newer (try python3 on macOS/Linux)

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Manual install

Use this if you'd rather clone the repo and manage Python yourself.

1. Get the code

git clone https://github.com/Codemod3/cad-mcp.git
cd cad-mcp

2. Install dependencies

Recommended — use a virtual environment so nothing pollutes your system Python:

python -m venv .venv
# Windows (PowerShell):
.venv\Scripts\Activate.ps1
# macOS / Linux:
source .venv/bin/activate

pip install -r requirements.txt

Or install as a proper command (cad-mcp) via pip:

pip install .

3. Verify it runs

python server.py

It should print a startup line to stderr and then wait silently (it's listening for an MCP client over stdio). Press Ctrl+C to stop. If you see no import errors, you're ready to connect a client.

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Connect to a client

Point your MCP client at server.py. Use the full absolute path to the file, and the same Python that has the dependencies installed.

Claude Desktop

Edit the config file:

• Windows: %APPDATA%\Claude\claude_desktop_config.json
• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "cad": {
      "command": "python",
      "args": ["C:\\full\\path\\to\\cad-mcp\\server.py"]
    }
  }
}

On macOS/Linux use "python3" and a /full/path/to/cad-mcp/server.py. If you used a virtualenv, point command at that venv's python, e.g. C:\\path\\to\\cad-mcp\\.venv\\Scripts\\python.exe.

Restart Claude Desktop. The CAD tools appear automatically.

Claude Code (CLI)

Easiest — no clone (needs uv):

claude mcp add cad -- uvx --from git+https://github.com/Codemod3/cad-mcp cad-mcp

If you cloned the repo instead:

claude mcp add cad -- python "C:\full\path\to\cad-mcp\server.py"

Scope (where the server is available):

claude mcp add cad --scope user  -- uvx --from git+https://github.com/Codemod3/cad-mcp cad-mcp   # all your projects
claude mcp add cad --scope project -- uvx --from git+https://github.com/Codemod3/cad-mcp cad-mcp  # writes .mcp.json for teammates

The repo also ships a ready .mcp.json — run Claude Code inside the project folder and the server loads automatically, no command needed.

Verify with /mcp, then just ask Claude to read or edit a CAD file. Remove with claude mcp remove cad.

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DWG support

DWG files need the free ODA File Converter installed once:

1. Download for your OS: https://www.opendesign.com/guestfiles/oda_file_converter
2. Install it. Default Windows path: C:\Program Files\ODA\ODAFileConverter <version>\ODAFileConverter.exe
3. Ensure it's on your PATH, or leave it at the default location where ezdxf finds it automatically.

Then use .dwg files exactly like .dxf — conversion is automatic. If the converter is missing, DWG tools return a clear error and DXF keeps working.

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Usage examples

Once connected, just talk to Claude:

• "Summarize this DXF file: C:\drawings\floor_plan.dxf"
• "What layers are in site_plan.dwg?"
• "Extract all the text annotations from my drawing."
• "Make an editable copy of plan.dxf, then add a circle radius 5 at (10,10) on a new layer called NOTES."
• "Draw the outline of a 20×10 room as a closed polyline, then export it to DWG."

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Supported entity types (read)

LINE, CIRCLE, ARC, LWPOLYLINE, TEXT, MTEXT, INSERT (block refs), DIMENSION, LEADER, ELLIPSE, SPLINE — all other types are still captured with their common attributes (layer, color, handle).

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Development

Run the test suite (offline, DXF only — no ODA converter needed):

pip install -r requirements.txt pytest pytest-asyncio
python -m pytest

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Troubleshooting

Symptom	Fix
Tools don't appear in the client	Use the absolute path to server.py; fully restart the client.
ModuleNotFoundError: ezdxf / fastmcp	The command python isn't the one with deps. Point it at your venv's python, or pip install -r requirements.txt for that interpreter.
DWG tools error about ODA	Install the ODA File Converter and make sure it's on PATH.
"Cannot edit a .dwg file in place"	Expected — run cad_create_editable_copy first, edit the .dxf copy, then cad_export_dwg.
Client shows a broken/empty connection	Something printed to stdout. This server logs only to stderr; if you added prints, remove them — stdout is the MCP protocol channel.

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License

MIT — see LICENSE.