Lambdacad MCP server

λ lambdacad-mcp

Let AI draw in your CAD. An MCP server for any AutoLISP-capable CAD — no COM, no SDK, no plugins. Pure AutoLISP. The reference adapter drives BricsCAD on Linux: the first MCP server for a professional DWG CAD on Linux.

"Draw a DN80 flange: front view, hatched section, dimensions — then model it in 3D."

Real-time capture, unedited: front view with bolt circle, hatched section, radial/diameter dimensions, leader, title block — then the same flange modeled as a 3D solid with an AI-written parametric AutoLISP loop and one boolean subtraction. ~20 seconds, 12 tool calls.

Why this exists

Every other MCP server for a professional DWG CAD (multiCAD-mcp, autocad-mcp, CAD-MCP, ...) talks to the CAD through Windows COM — none of them can run on Linux, and none of them does real 3D.

BricsCAD is the professional DWG CAD that does run natively on Linux. This server drives it through a mechanism that needs no API at all: an AutoLISP file bridge. The MCP server writes LISP expressions to a file, triggers a tiny MCP command inside the CAD, and reads the result back. That's the whole trick — and it unlocks everything the CAD can do, including 3D solid modeling.

Because the bridge is plain AutoLISP + standard DXF entmake + AutoCAD-compatible commands, it is portable by construction: AutoCAD, ARES Commander (also Linux-native!), ZWCAD, GstarCAD and the IntelliCAD family all speak the same language. Porting means swapping the autoload file name and the keystroke trigger — adapters welcome.

MCP client (Claude, Cursor, ...)            BricsCAD (Linux)
        │                                        │
        ▼                                        ▼
  server.py (FastMCP, 128 tools)          c:MCP AutoLISP command
        │        writes LISP  ──►  /tmp/mcp_bricscad.in
        │        triggers via xdotool ──► reads, evals line by line
        │        reads result ◄──  /tmp/mcp_bricscad.out

What it can do

Shortened. The full README is on GitHub.