posecode-mcp

posecode-mcp

A Model Context Protocol server for Posecode. It gives any MCP-capable agent (Claude Desktop, Cursor, …) a native way to show movement: learn the .posecode language, validate a movement against healthy range-of-motion limits, and get a link that animates it as a 3D figure.

This closes the loop the playground left open — no copy-pasting a system prompt or shuttling text between a chat window and the editor.

Tools

Tool	What it does
posecode_authoring_guide	Returns the Posecode authoring guide (grammar, joints, actions, example) so the model can write valid .posecode.
validate_posecode	Parses a .posecode document and returns errors plus any range-of-motion safety clamps (the angles that were out of healthy range).
render_posecode	Validates, then returns a permalink that renders the movement in the Posecode playground. Hand it to the user to watch.

validate_posecode / render_posecode flag invalid documents as MCP error results so the model knows to fix and retry.

Run

It's a TypeScript server; run it with tsx (no build step needed):

npm start -w posecode-mcp          # tsx src/stdio.ts

Add to Claude Desktop / Cursor

{
  "mcpServers": {
    "posecode": {
      "command": "npx",
      "args": ["-y", "tsx", "/ABSOLUTE/PATH/TO/posecode/packages/posecode-mcp/src/stdio.ts"],
      "env": { "POSECODE_BASE_URL": "https://posecode.org" }
    }
  }
}

POSECODE_BASE_URL is optional — it sets the playground that render permalinks point at (defaults to the hosted playground).

How it fits

render_posecode builds its links with posecode-share — the same permalink primitive the playground uses — and validates with posecode-parser. The server holds no rendering itself; 3D math runs client-side when the link is opened.