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, P&ID diagrams, and technical documentation through conversational prompts.

🚀 Key Features

Core Drawing Operations

• Generates and executes AutoLISP code in AutoCAD LT 2024+

• Creates basic shapes (lines, circles, polylines, text)

• Handles block insertion with comprehensive attribute management

• Supports advanced geometry (arcs, ellipses, rectangles)

• Provides robust layer creation and management

• Creates hatches and dimensions for technical drawings

P&ID and Process Engineering (NEW)

• CTO Library Integration: Complete access to CAD Tools Online P&ID Symbol Library (600+ ISA 5.1-2009 standard symbols)

• Intelligent Attribute Handling: Proper block attributes for equipment schedules and valve lists

• Process Equipment: Pumps, valves, tanks, instruments, and process equipment

• Standard Annotations: Equipment tags, descriptions, and line numbers

• Layer Management: Industry-standard P&ID layer organization

Performance Optimizations

• Fast Mode: Optimized execution with minimal delays (80% speed improvement)

• Batch Operations: Create multiple objects in single operations

• Clipboard Integration: Efficient large script execution

• Smart Loading: Essential LISP files only for faster startup

📋 Prerequisites

• AutoCAD LT 2024 or newer (with AutoLISP support)

• Python 3.10 or higher

• Claude Desktop or other MCP client application

• Optional: CAD Tools Online P&ID Symbol Library (for full P&ID functionality)

🛠️ Setup Instructions

1. Install Dependencies

2. Configure Claude Desktop

For users WITH CTO Library:

For users WITHOUT CTO Library:

3. CTO Library Setup (Optional but Recommended)

If you have the CAD Tools Online P&ID Library:

1. Install the CTO library to C:\PIDv4-CTO\

2. Verify the following directories exist:

   • C:\PIDv4-CTO\VALVES\

   • C:\PIDv4-CTO\EQUIPMENT\

   • C:\PIDv4-CTO\PUMPS-BLOWERS\

   • C:\PIDv4-CTO\TANKS\

   • (and other standard categories)

If you DON'T have the CTO Library:

• Use server_lisp.py instead of server_lisp_fast.py

• P&ID tools will not work, but all basic drawing operations remain available

• You can still create custom blocks and use standard AutoCAD functionality

4. Start AutoCAD and Server

1. Launch AutoCAD LT

   • Create or open a drawing

   • Ensure command line is visible

2. Start the Server

   # For users with CTO library (recommended) start_fast_server.bat # For users without CTO library start_lisp_server.bat

3. Test the Connection

   test_connection.bat

🔧 Available Tools

Basic Drawing Tools

• create_line: Draw lines between points

• create_circle: Create circles with center and radius

• create_text: Add text labels with rotation support

• create_polyline: Create polylines from point series

• create_rectangle: Create rectangles from corner points

• batch_create_lines: Create multiple lines efficiently

• batch_create_circles: Create multiple circles efficiently

• batch_create_texts: Create multiple text entities efficiently

Block and Layer Management

• insert_block: Insert blocks with attributes and positioning

• set_layer_properties: Create/modify layers with full properties

• move_last_entity: Move recently created entities

• update_block_attribute: Modify block attributes after insertion

P&ID and Process Tools (CTO Library Required)

• setup_pid_layers: Create standard P&ID drawing layers

• insert_pid_symbol: Insert any symbol from CTO library

• insert_pid_equipment_with_attribs: Insert equipment with proper attributes

• insert_valve_with_attributes: Insert valves with CTO attributes

• insert_equipment_tag: Add equipment identification tags

• insert_equipment_description: Add equipment description blocks

• insert_line_number_tag: Add process line identification

• draw_process_line: Draw process piping between points

• connect_equipment: Connect equipment with orthogonal routing

• add_flow_arrow: Add directional flow indicators

Advanced Operations

• create_arc: Create arcs with center, radius, and angles

• create_ellipse: Create ellipses with major axis and ratio

• create_mtext: Add multiline formatted text

• create_linear_dimension: Add linear dimensions

• create_hatch: Add hatching to closed areas

• list_pid_symbols: List available symbols by category

📖 Usage Examples

Basic Drawing

P&ID Creation (with CTO Library)

Process Flow Creation

Batch Operations

🚧 Configuration for Users Without CTO Library

If you don't have the CAD Tools Online library, you can still use this MCP server effectively:

1. Use the Standard Server

Replace the server command with:

2. Modify P&ID Tool Calls

The following tools will not work without CTO library:

• insert_pid_symbol

• insert_pid_equipment_with_attribs

• insert_valve_with_attributes

• list_pid_symbols

3. Alternative Approaches

Instead of CTO symbols, you can:

• Use standard AutoCAD blocks

• Create simple geometric representations

• Use text labels for equipment identification

• Import your own symbol library

4. Example Alternative Usage

📁 LISP Library Structure

The server loads these LISP files for functionality:

⚡ Performance Optimization

Fast Mode Benefits

• 80% faster drawing operations using batch tools

• 90% faster server initialization with essential files only

• Clipboard-based script execution for complex operations

Batch Operation Examples

Performance Settings

Adjust performance based on your system:

🔍 Troubleshooting

Common issues and solutions:

LISP Loading Issues

• Problem: "LOAD failed" errors

• Solution: Add LISP directory to AutoCAD trusted paths

• See: TROUBLESHOOTING.md

CTO Library Issues

• Problem: "File not found" for P&ID symbols

• Solution: Verify CTO installation path or use standard server

• Alternative: Use server_lisp.py without P&ID functionality

Window Focus Problems

• Problem: Commands not reaching AutoCAD

• Solution: Ensure AutoCAD is active, run as Administrator

• See: TROUBLESHOOTING.md

📊 What's New in This Version

Version 2.0 Features

• ✅ Complete CTO Library Integration (600+ P&ID symbols)

• ✅ Intelligent Block Attributes for equipment schedules

• ✅ Fast Mode Server with 80% performance improvement

• ✅ Batch Operations for multiple object creation

• ✅ Process Engineering Tools for P&ID creation

• ✅ Industry Standard Layers for professional drawings

• ✅ Enhanced Error Handling and troubleshooting guides

Migration from v1.0

Users of the original version should:

1. Update to server_lisp_fast.py for better performance

2. Add CTO library path if available

3. Review new P&ID tools for process drawings

4. Update Claude Desktop configuration

📄 License

MIT License - See LICENSE file for details

🤝 Contributing

Contributions are welcome! Please:

1. Fork the repository

2. Create a feature branch

3. Test with both CTO and non-CTO configurations

4. Submit a pull request with clear documentation

📞 Support

• Issues: GitHub Issues

• Documentation: TROUBLESHOOTING.md

• Performance: PERFORMANCE_OPTIMIZATION.md

For detailed troubleshooting and advanced configuration, see the additional documentation files in this repository.