Build123d MCP: MCP server, setup and security

What Build123d MCP does

According to its repository: “Create, inspect and iterate on 3D geometry with build123d parametric CAD: render PNG/SVG views, measure geometry and export STEP/STL.”

An MCP server gives an AI agent extra tools it calls during the conversation: the agent reads their description, decides to use them and gets the result back. Build123d MCP is listed under Design, art and accessibility, a category of 95 servers in the directory, where it ranks #26 by stars.

Topics declared by the repository: ai-tools, build123d, cad, python3.

Installing and connecting Build123d MCP

Distribution modes declared in the official MCP registry:

• PyPI package (Python, started with uvx or pip)

Like any MCP server, you declare it in your client's configuration (Claude Desktop, Claude Code, Cursor, VS Code, Codex…): a name, the command that starts it or its URL, and any environment variables. The client then starts it and lists its tools. Project language: Python. Listed systems: macOS, Windows, Linux.

Security: what to check

An MCP server runs code with the rights you give it, and the model reads its tool descriptions: a malicious or compromised server can hijack the agent. Read the code, or pick a maintained and widely used server, before connecting it.

None of the risk signals we track (system access, secrets, missing licence, abandonment) applies to Build123d MCP. That does not replace reading the code.

Good practice: grant only the rights needed (least privilege), require human approval for irreversible actions, and run the AI agent security check.

Project activity and maintenance

Created on April 30, 2026, the pzfreo/build123d-mcp repository has 130 stars and 17 forks, with 60 open issues. It has more stars than 71% of the servers in the directory. It received changes this month. Version published in the registry: 0.3.91 (October 15, 2026).

Stars measure attention, not quality: a recent, heavily promoted project can collect them fast, while a useful but niche server will have few.