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

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

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

Start AutoCAD LT:
- Launch AutoCAD LT
- Create or open a drawing
- Ensure the AutoCAD window title includes "AutoCAD" and the drawing name (".dwg")
Start the Server:
- Run start_lisp_server.bat as Administrator
- Alternatively, use restart_fixed_server.bat if you encounter issues with LISP loading
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
create_rectangle: Create a rectangle using two opposite corners
create_arc: Create an arc from center, radius and start/end angles
create_ellipse: Create an ellipse with major axis and ratio
create_mtext: Add multiline text with width and optional formatting
create_wipeout_from_points: Create a wipeout mask from a list of points
move_last_entity: Move the most recently created entity by a delta
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:

error_handling.lsp: Base error handling and validation functions
basic_shapes.lsp: Core functions for creating lines, circles, and text
drafting_helpers.lsp: Functions for block manipulation, layer management, and connecting elements
block_id_helpers.lsp: Functions for finding and manipulating blocks by ID attribute
selection_and_file.lsp: Selection set management and file operations
advanced_geometry.lsp: Extended geometry creation and manipulation
advanced_entities.lsp: Rectangle, arc, ellipse, mtext, and wipeout helpers
entity_modification.lsp: Basic entity modification commands
annotation_helpers.lsp: Text and dimension creation tools
layout_management.lsp: Functions for managing layouts and viewports

Usage Examples

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"
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"
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"
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'"
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")

Recent Fixes

Improved AutoCAD window detection so the server works even if the title only shows the drawing file name.
Corrected the insert_block command construction which previously missed a space between scale and rotation values.

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.

AutoCAD LT AutoLISP MCP服务器