sweethome3d-mcp-server

What is sweethome3d-mcp-server?

A plugin for Sweet Home 3D that embeds an MCP (Model Context Protocol) server directly inside the application, allowing Claude and other AI assistants to control Sweet Home 3D over HTTP — create walls, place furniture, render photos, and more — without any external proxy or separate server process.

How to use sweethome3d-mcp-server?

Download the latest .sh3p file from Releases, copy it to your Sweet Home 3D plugins folder (see README for OS-specific paths), then restart Sweet Home 3D. The MCP server starts automatically on port 9877. Configure Claude Desktop or Claude Code with the HTTP endpoint http://localhost:9877/mcp. The plugin also has an auto-configure button under Tools → MCP Server.

Key features of sweethome3d-mcp-server

• 42 commands across 12 categories (scene, walls, furniture, rooms, etc.)
• Runs entirely inside Sweet Home 3D — no external proxy needed
• Automatic startup on port 9877 with a settings dialog
• Supports undo timeline via in-memory snapshots (checkpoints)
• Batch command execution and auto‑registration of new command handlers
• Stable UUIDs for all objects; coordinate system in centimeters

Use cases of sweethome3d-mcp-server

• AI‑assisted home design — let a language model create and modify floor plans
• Automated 3D scene generation from text descriptions
• Export plans as SVG, PNG, or Wavefront OBJ for further processing
• Batch furniture placement or wall creation in a single request
• Integration with Claude Desktop or Claude Code for iterative design

FAQ from sweethome3d-mcp-server

What are the system requirements?

Sweet Home 3D 6.0 or newer and Java 11 or newer. The JRE bundled with very old SH3D builds (e.g., 32‑bit Windows with JRE 1.8) will fail silently.

On which port does the server run?

The HTTP (JSON‑RPC 2.0) server listens on 127.0.0.1:9877 with the endpoint /mcp.

Why won’t the MCP server start on macOS?

The Mac App Store build of Sweet Home 3D is sandboxed and lacks the network server entitlement. Use the standalone installer from sweethome3d.com instead.

How do I configure Claude to use the plugin?

Add "sweethome3d": {"type": "http", "url": "http://localhost:9877/mcp"} to your Claude Desktop claude_desktop_config.json or Claude Code .mcp.json. The plugin can write this automatically via the Tools → MCP Server dialog.

Where does the plugin look for Sweet Home 3D JARs when building from source?

The build script checks your local SH3D installation first (fastest, works offline), then falls back to downloading SweetHome3D.jar from SourceForge. The three Java3D JARs are included in lib/.