Bonsai MCP

A local Model Context Protocol server that bridges AI clients (Claude Desktop, Claude Code, Cursor, VS Code, and any MCP-compatible tool) to a running Blender + Bonsai (BlenderBIM) session.

Bonsai MCP exposes a focused, well-defined tool surface for inspecting the active Blender scene, querying the loaded IFC project, and running Python inside Blender. It is local-first: nothing listens on a non-loopback interface.

At a glance

• 8 tools, split into 5 QUERY (read-only) and 3 EDIT (mutating) operations. The category appears as a [QUERY] or [EDIT] prefix in every tool description and via MCP's Tool.annotations.readOnlyHint.
• Two moving parts: a Python MCP server (this package) plus a Blender add-on that runs inside Blender.
• Talks over 127.0.0.1 only, with a length-prefixed JSON protocol.
• Built directly on the official mcp Python SDK and Pydantic, with no bespoke framework dependency.

Where to next

• Installation
• Client setup
• Tools reference
• Safety
• Troubleshooting