AutoCAD LT AutoLISP MCP Server

This MCP server enables natural language control of AutoCAD LT 2024/2025 through AutoLISP code generation and execution. It bridges Claude or other LLM clients with AutoCAD LT for creating engineering drawings through conversational prompts.

Features

• Generates and executes AutoLISP code in AutoCAD LT
• Creates basic shapes (lines, circles, polylines, text)
• Handles block insertion with attribute management
• Supports connecting blocks with lines between named connection points
• Arranges multiple blocks in sequence with custom spacing
• Provides robust layer creation and management
• Creates hatches and dimensions for technical drawings
• Allows entity rotation and manipulation
• Supports direct custom AutoLISP code execution
• Enables text-to-CAD functionality through natural language

Prerequisites

• AutoCAD LT 2024 or newer (with AutoLISP support)
• Python 3.10 or higher
• Claude Desktop or other MCP client application

Setup Instructions

1. Install Dependencies:

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

2. Configure Claude Desktop:

   • Open Claude Desktop settings
   • Edit the configuration file to include:

   {
     "mcpServers": {
       "autocad-lisp": {
         "command": "path\\to\\autocad-mcp\\venv\\Scripts\\python.exe",
         "args": ["path\\to\\autocad-mcp\\server_lisp.py"]
       }
     }
   }
   

   • Alternatively, you can use the included claude_desktop_config_lisp.json as a template

3. Start AutoCAD LT:

   • Launch AutoCAD LT
   • Create or open a drawing
   • Make sure the window title contains "AutoCAD LT" and "Drawing"

4. Start the Server:

   • Run start_lisp_server.bat as Administrator
   • Alternatively, use restart_fixed_server.bat if you encounter issues with LISP loading

5. Test the Connection:

   • Run test_connection.bat to verify proper functionality

Available Tools

• get_autocad_status: Check connection to AutoCAD
• create_line: Draw a line between two points
• create_circle: Create a circle with defined center and radius
• create_text: Add text labels at specified coordinates
• insert_block: Insert a block with optional ID attribute, scale, and rotation
• connect_blocks: Connect two blocks with a line between named connection points
• label_block: Add a text label to a block
• arrange_blocks: Arrange multiple blocks in a sequence with custom spacing
• create_polyline: Create a polyline from a series of points
• rotate_entity_by_id: Rotate an entity around a base point
• create_linear_dimension: Add a linear dimension between two points
• create_hatch: Add hatching to a closed polyline area
• set_layer_properties: Create or modify layers with color, linetype, lineweight, etc.
• execute_custom_autolisp: Run custom AutoLISP code directly

LISP Library Structure

The server loads multiple LISP files for functionality:

1. error_handling.lsp: Base error handling and validation functions
2. basic_shapes.lsp: Core functions for creating lines, circles, and text
3. drafting_helpers.lsp: Functions for block manipulation, layer management, and connecting elements
4. block_id_helpers.lsp: Functions for finding and manipulating blocks by ID attribute
5. selection_and_file.lsp: Selection set management and file operations
6. advanced_geometry.lsp: Extended geometry creation and manipulation
7. annotation_helpers.lsp: Text and dimension creation tools
8. layout_management.lsp: Functions for managing layouts and viewports

Usage Examples

1. Basic Drawing Operations:

   • "Draw a line from coordinates (100,100) to (200,150)"
   • "Create a circle at (150,150) with radius 25"
   • "Add text 'System Title' at position (100,200)"
   • "Create a polyline with points at (10,10), (50,50), (100,10) and close it"

2. Block Operations:

   • "Insert a block named 'PUMP' at position (100,100) with ID 'P-101'"
   • "Label the block with ID 'P-101' as 'Feed Pump'"
   • "Connect block 'P-101' to 'V-201' on the 'Piping' layer"
   • "Rotate the block 'P-101' by 45 degrees around its insertion point"

3. Multi-Block Operations:

   • "Arrange blocks 'PUMP', 'VALVE', and 'TANK' starting at (50,100) going right with 30 units spacing"
   • "Create a layer named 'Equipment' with color 'yellow'"
   • "Add a dimension between the two blocks showing the distance"

4. Advanced Operations:

   • "Create a closed polyline and add ANSI31 hatching inside it"
   • "Create a dimension showing the diameter of the circle"
   • "Set the current layer to 'Dimensions' with color 'cyan' and lineweight '0.30mm'"

5. Custom AutoLISP:

   • "Execute this AutoLISP code to create a custom function: (defun c:my-function ...)"

Limitations

• Requires AutoCAD LT 2024 or newer with AutoLISP support
• Relies on window focus and keyboard simulation for command execution
• User should not interact with AutoCAD while commands are being sent
• Limited to 2D drawing operations
• Connection points for blocks use predefined connection point names (CONN_DEFAULT1, CONN_DEFAULT2)
• Layer colors must be specified as strings (e.g., "red", "yellow", "120")

Troubleshooting

See the TROUBLESHOOTING.md file for common issues and solutions. Common issues include:

• LISP files failing to load
• Window focus issues with AutoCAD
• Function cancelled errors
• Communication problems between the server and AutoCAD

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.