AutoCAD MCP Server

AutoCAD MCP Server

A production-grade Model Context Protocol (MCP) server for AutoCAD on Windows, enabling AI assistants (Claude Desktop, ChatGPT, Cursor, etc.) to control AutoCAD through natural language.

Features

• 10 Comprehensive MCP Tools for CAD operations
• AutoCAD COM API Integration for native Windows automation
• Natural Language Control - "Draw a 100x50 rectangle" → creates geometry
• Automatic Connection Management with reconnection logic
• Full Type Hints & Pydantic Validation for safety
• Production Logging for debugging and monitoring
• Unit Tests covering all tools and edge cases
• Fast & Lightweight using FastMCP framework

Tech Stack

• Python 3.11+
• FastMCP - MCP framework
• pyautocad - AutoCAD COM wrapper
• pywin32 - Windows COM support
• Pydantic - Data validation
• uv - Fast Python package manager

Available Tools

Drawing Tools

1. create_line - Draw a line between two points
   • Parameters: x1, y1, x2, y2
   • Returns: Object ID of created line
2. create_circle - Draw a circle
   • Parameters: center_x, center_y, radius
   • Returns: Object ID of created circle
3. create_rectangle - Draw a rectangle
   • Parameters: x, y, width, height
   • Returns: List of object IDs (polyline + entities)
4. create_text - Add text annotation
   • Parameters: text, x, y, height
   • Returns: Object ID of created text

Layer Management

1. create_layer - Create a new layer
   • Parameters: layer_name
   • Returns: Layer name (or error if exists)
2. list_layers - List all layers in document
   • No parameters
   • Returns: List of layer names

Analysis & Measurement

1. calculate_area - Calculate area of closed shape
   • Parameters: object_id
   • Returns: Calculated area value

Document Operations

1. save_drawing - Save active drawing
   • Parameters: file_path (optional, defaults to current)
   • Returns: Success message with file path
2. export_pdf - Export drawing to PDF
   • Parameters: output_path
   • Returns: Success message with PDF path
3. get_active_document - Get active document info
   • No parameters
   • Returns: Document name and full path

Installation

Prerequisites

• Windows 10/11 (AutoCAD COM API is Windows-only)
• AutoCAD 2020+ installed and running
• Python 3.11+ with pip
• uv package manager (recommended)

Step 1: Clone Repository

git clone https://github.com/yourusername/autocad-mcp-server.git cd autocad-mcp-server

Step 2: Install Dependencies

Using uv (fastest):

uv sync

Or using pip:

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

Step 3: Install pywin32 COM Support

After installing pywin32, register COM components:

python -m pip install --upgrade pywin32 python Scripts/pywin32_postinstall.py -install

Or if using uv:

uv run python -m pip install --upgrade pywin32 uv run python Scripts/pywin32_postinstall.py -install

Step 4: Verify Installation

Test that AutoCAD COM is accessible

python -c "import win32com.client; acad = win32com.client.GetObject(class='AutoCAD.Application'); print(f'AutoCAD {acad.Version} detected')"

AutoCAD Prerequisites

1. AutoCAD Must Be Running

The server connects to a running AutoCAD instance via COM:

Start AutoCAD before running the MCP server

AutoCAD will be running in the background

2. Enable COM Automation (Usually Default)

AutoCAD COM is enabled by default. To verify:

1. Open AutoCAD
2. Go to Tools → Options → System
3. Ensure "OLE Support" is enabled

3. AutoCAD COM Version Support

AutoCAD Version	COM Version	Python Support
2024	24.x	✅ Yes
2023	23.x	✅ Yes
2022	22.x	✅ Yes
2021	21.x	✅ Yes
2020	20.x	✅ Yes

Configuration

Environment Variables

Create a .env file (copy from .env.example):

AutoCAD connection timeout in seconds

AUTOCAD_TIMEOUT=10

Connection retry attempts

RETRY_ATTEMPTS=3

Logging level: DEBUG, INFO, WARNING, ERROR

LOG_LEVEL=INFO

Server host and port

MCP_HOST=127.0.0.1 MCP_PORT=8000

Usage

Option 1: Run as Standalone MCP Server

Terminal 1: Start AutoCAD (if not already running)

Open AutoCAD manually

Terminal 2: Start MCP server

python -m src.server

The server will:

• Detect running AutoCAD instance
• Register all tools with MCP
• Listen for tool calls
• Reconnect if AutoCAD restarts

Option 2: Claude Desktop Integration

Step 1: Get Server URL

When running locally, the server is available at:

stdio://python -m src.server

Step 2: Configure Claude Desktop

Edit ~/.config/Claude/claude_desktop_config.json (Windows):

{ "mcpServers": { "autocad": { "command": "python", "args": ["-m", "src.server"], "cwd": "d:/autocad-mcp-server" } } }

On Windows, the config is at:

C:\Users\[YourUsername]\AppData\Roaming\Claude\claude_desktop_config.json

Step 3: Restart Claude Desktop

Close and reopen Claude Desktop. The AutoCAD tools will appear in the Tools section.

Option 3: ChatGPT Custom Actions

Create a custom action in ChatGPT with this schema pointing to your running MCP server.

Option 4: Cursor IDE Integration

In Cursor settings, configure the MCP server endpoint:

{ "mcpServers": { "autocad": { "command": "python", "args": ["-m", "src.server"] } } }

Example Prompts

Once connected, use natural language to control AutoCAD:

Basic Drawing

• "Draw a line from (0, 0) to (100, 50)" → Calls create_line with coordinates
• "Create a circle at center (50, 50) with radius 25" → Calls create_circle
• "Draw a 100x50 rectangle at origin" → Calls create_rectangle

Text & Annotation

• "Add text 'WALL-A' at coordinates (10, 20) with height 5" → Calls create_text

• "Create a new layer called 'Fixtures'" → Calls create_layer

• "Show me all layers in the drawing" → Calls list_layers

Analysis

• "Calculate the area of object with ID 'ABC123'" → Calls calculate_area

Document Management

• "Save the drawing" → Calls save_drawing
• "Export the drawing to PDF at C:\output\plan.pdf" → Calls export_pdf
• "What's the active document name?" → Calls get_active_document

Troubleshooting

Issue: "AutoCAD not found" or Connection Refused

Solution:

1. Open AutoCAD manually before starting the MCP server
2. Verify AutoCAD is running: Task Manager → search for "acad"
3. Check AutoCAD version supports COM (2020+)

Debug: Test COM access

python -c "from src.autocad_client import AutoCADClient; c = AutoCADClient(); print(c.get_document_info())"

Issue: "Module not found" errors

Solution:

Reinstall dependencies

pip install -r requirements.txt

Or with uv

uv sync --reinstall

Issue: pywin32 COM not registered

Solution:

On some systems, run as Administrator

Issue: "Permission denied" when saving files

Solution:

1. Ensure the output directory exists and is writable
2. Run AutoCAD as Administrator if needed
3. Check file paths use forward slashes or double backslashes:

Good

"C:/output/drawing.pdf"
"C:\output\drawing.pdf"

Bad

"C:\output\drawing.pdf" # Single backslashes interpreted as escape codes

Issue: MCP Server won't start

Solution:

1. Check Python version: python --version (should be 3.11+)
2. Verify dependencies: pip list | grep -E "fastmcp|pyautocad|pydantic"
3. Check logs:

Run with DEBUG logging

LOG_LEVEL=DEBUG python -m src.server

Issue: Tools not appearing in Claude Desktop

Solution:

1. Verify config file exists: C:\Users\[You]\AppData\Roaming\Claude\claude_desktop_config.json
2. Check JSON syntax is valid (use jsonlint.com)
3. Restart Claude Desktop completely
4. Check server logs for startup errors

Issue: AutoCAD crashes or becomes unresponsive

Solution:

1. The server includes timeout and error handling
2. If AutoCAD freezes, kill the process and restart
3. Server will automatically reconnect when AutoCAD restarts
4. Check for unsupported AutoCAD operations (e.g., complex geometry)

Testing

Run the unit test suite:

Run all tests

pytest

Run with coverage

pytest --cov=src

Run specific test file

pytest tests/test_models.py

Run with verbose output

pytest -v

Test coverage includes:

• ✅ Pydantic model validation
• ✅ Tool parameter validation
• ✅ AutoCAD connection logic
• ✅ API endpoint functionality
• ✅ Error handling and edge cases

Project Structure

autocad-mcp-server/
├── src/
│   ├── __init__.py
│   ├── server.py                 # MCP server entrypoint
│   ├── autocad_client.py         # AutoCAD COM wrapper
│   ├── models.py                 # Pydantic validation models
│   └── tools/
│       ├── __init__.py           # Tool registry
│       ├── drawing.py            # Line, circle, rectangle, text
│       ├── layers.py             # Layer management
│       ├── dimensions.py         # Area calculation
│       └── export.py             # Save and PDF export
├── tests/
│   ├── test_models.py            # Model validation tests
│   ├── test_server.py            # API endpoint tests
│   └── test_tools.py             # Tool handler tests
├── pyproject.toml                # uv/pip dependencies
├── .env.example                  # Environment template
└── README.md                      # This file

Architecture

AutoCAD Connection

┌─────────────────────────────────────────┐
│     Claude Desktop / ChatGPT / etc      │
└──────────────────┬──────────────────────┘
                   │
                   │ (MCP Protocol)
                   │
┌──────────────────▼──────────────────────┐
│     MCP Server (FastMCP)                │
│  ├─ Tool Registry                       │
│  ├─ Request Dispatcher                  │
│  └─ Pydantic Validators                 │
└──────────────────┬──────────────────────┘
                   │
                   │ (Python API)
                   │
┌──────────────────▼──────────────────────┐
│     AutoCAD Client (pyautocad)          │
│  ├─ Connection Manager                  │
│  ├─ Retry Logic                         │
│  └─ Error Handler                       │
└──────────────────┬──────────────────────┘
                   │
                   │ (COM Automation)
                   │
┌──────────────────▼──────────────────────┐
│     AutoCAD Application (COM)           │
│  ├─ Drawing API                         │
│  ├─ Layer Management                    │
│  └─ Document Operations                 │
└─────────────────────────────────────────┘

Performance Notes

• Fast - Direct COM calls, no network overhead
• Lightweight - Minimal dependencies
• Reliable - Auto-reconnection on AutoCAD restart
• Safe - Full input validation with Pydantic
• Concurrent - Handles multiple AI assistant requests

Security Considerations

• ✅ Runs locally on Windows (no cloud exposure)
• ✅ Input validation on all tool parameters
• ✅ Type-safe with Pydantic models
• ✅ Error handling prevents information leakage
• ⚠️ AutoCAD file access - ensure proper file permissions
• ⚠️ When exposing via network, use authentication/TLS

Contributing

Pull requests welcome! Areas for enhancement:

• Additional drawing primitives (arc, polyline, spline)
• Block/component support
• Dimension annotations
• Hatch patterns
• Custom properties
• Multi-document support
• macOS/Linux via parallel AutoCAD alternatives

License

MIT - See LICENSE file

Support

• 📧 Issues: GitHub Issues
• 💬 Discussions: GitHub Discussions
• 📚 Docs: AutoCAD COM API Reference
• 🔗 MCP Protocol: Model Context Protocol Spec

Changelog

v1.0.0 (2026-06-05)

• Initial release
• 10 core CAD tools
• Claude Desktop integration
• Full test coverage
• Production-ready code

Roadmap

• AutoCAD Web API support for cloud deployments
• Real-time drawing updates with WebSocket
• Advanced geometry operations (offset, trim, extend)
• Material/property management
• CAM integration
• Version control for drawing changes

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