Allplan MCP Server

FastMCP server that exposes the local Allplan Python host as MCP tools.

The existing Allplan PythonPart starts a small local HTTP host at 127.0.0.1:5679. This package adds a FastMCP server in front of it, so agents can call MCP tools over Streamable HTTP at /mcp.

Setup

uv sync

Register the Allplan PythonPart bridge on the Windows machine where Allplan is installed:

utils\register_python_host.cmd

By default this copies the bridge to:

%USERPROFILE%\Documents\Nemetschek\Allplan\2026\Usr\Local\PythonParts\PythonHost
%USERPROFILE%\Documents\Nemetschek\Allplan\2026\Usr\Local\PythonPartsScripts\PythonHost

For a different Allplan version:

utils\register_python_host.cmd --allplan-version 2025

In Allplan, start the StartPythonHost PythonPart after registration. It must keep running while the MCP server is being used.

Run locally

uv run allplan-mcp

By default this starts the MCP server at:

http://127.0.0.1:8888/mcp

Useful environment variables:

ALLPLAN_HOST_URL=http://127.0.0.1:5679
MCP_HOST=127.0.0.1
MCP_PORT=8888
MCP_PATH=/mcp

Tools

• allplan_health: checks whether the Allplan host is reachable.
• get_allplan_version: returns the running Allplan version.
• get_all_object_names: returns display names for elements in the current document.
• create_cube: creates a cube in the current document.
• create_box: creates a rectangular cuboid in the current document.
• execute_python: executes sandboxed Python inside the running Allplan host

Skill resources

Bundled skills are also exposed through MCP resources so clients can discover and read them through the protocol.

Simple folder layout:

src/allplan_mcp/allplan_skills/
  api-reference/
    SKILL.md
    assets/
    scripts/
  geometry/
    SKILL.md
    assets/
    scripts/
  rebar/
    SKILL.md
    assets/
    scripts/
  utilities/
    SKILL.md
    assets/
    scripts/

Resource URIs:

• allplan://skills
• allplan://skills/api-reference
• allplan://skills/geometry
• allplan://skills/rebar
• allplan://skills/utilities
• allplan://skills/{skill_name}/assets/{asset_name}
• allplan://skills/{skill_name}/scripts/{script_name}

The scripts are simple templates. They are meant to guide generated code and do not depend on cross imports between skill folders.

Notes

• POST execution exploration

Sandboxed exec

The bridge exposes a sandboxed Python execution path for local experiments.

Behavior:

• The raw Allplan bridge accepts POST /execute-python
• The external MCP server exposes execute_python(...)
• The endpoint remains bound to 127.0.0.1
• Imports are blocked by AST validation
• Private and dunder attribute access is blocked by AST validation
• Only a restricted builtin whitelist is available at runtime

Do not expose execute_python through ngrok or a shared agent setup.