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 process engineering symbols (pumps, vessels, heat exchangers)
• Draws piping connections and complete process diagrams
• Provides direct access to AutoLISP for custom drawing operations
• Supports 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:

   cd pathto\mcp-servers\autocad-mcp
   python -m venv venv
   venv\Scripts\activate
   pip install mcp[cli] keyboard pyperclip pywin32
   

2. Configure Claude Desktop:

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

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

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

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
• create_equipment_symbol: Draw process equipment symbols (vessel, pump, exchanger)
• create_pipe: Connect equipment with pipe lines
• create_simple_pfd: Create a complete process flow diagram
• execute_custom_autolisp: Run custom AutoLISP code directly

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 'Cooling System' at position (100,200)"

2. Process Equipment:

   • "Draw a pump at (100,100) with tag P-101"
   • "Create a vessel at (200,150) labeled TK-101"
   • "Place a heat exchanger at (150,120)"

3. Process Flow Diagrams:

   • "Create a simple process flow diagram starting at (50,100)"
   • "Draw a pump feeding into a heat exchanger and then to a storage vessel"
   • "Create a PFD for a water treatment system with feed pump, filter, and storage tank"

4. Custom AutoLISP:

   • "Execute this AutoLISP code to create a custom piping configuration: (defun c:create-pipe-bend ...)"

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

Troubleshooting

• If connection fails, ensure AutoCAD LT is running with a drawing open
• Verify window title contains "AutoCAD LT" and "Drawing"
• Run the server as Administrator
• Check that your AutoCAD LT version supports AutoLISP (2024 or newer)
• Look at server console for detailed error messages