robosimtools-mcp

An MCP server that exposes robosimtools.com's 12 robotics/simulation tools to AI agents. The tool logic here is the same code robosimtools.com serves to your browser — vendored into lib/ so this server is self-contained. All computation is local; nothing is uploaded.

This is the open-source MCP server for robosimtools.com. The website itself is a separate project; only the browser tools it already ships publicly are included here (see Vendored modules).

Tools

Every tool is read-only with no side effects.

Related MCP server: openscad-mcp

Install

git clone https://github.com/RahulRajelli/robosimtools-mcp
cd robosimtools-mcp
npm install

Use it

The server talks over stdio, so any client that supports local MCP servers works. Replace the path below with wherever you cloned the repo.

Claude Desktop

Add to claude_desktop_config.json and restart:

{
  "mcpServers": {
    "robosimtools": {
      "command": "node",
      "args": ["ABSOLUTE/PATH/TO/robosimtools-mcp/src/index.js"]
    }
  }
}

OpenAI Codex CLI

Add to ~/.codex/config.toml and restart Codex:

[mcp_servers.robosimtools]
command = "node"
args = ["ABSOLUTE/PATH/TO/robosimtools-mcp/src/index.js"]

ChatGPT's own connectors target remote (HTTP) MCP servers — for this local stdio server, use the Codex CLI or Claude Desktop.

Then ask, e.g.: "Convert the quaternion (w=0.707, x=0, y=0, z=0.707) to URDF roll-pitch-yaw", or "Turn this STEP file into a URDF with computed inertia."

Test

npm test             # 39 known-answer checks across all 12 tools
npm run test:e2e     # connects a real MCP client over stdio
npm run test:install # packs, installs to a temp dir, drives the installed copy

test:install is the one that matters before a release: it verifies the published artifact — that the files allowlist is complete, the bin shebang works, and the lazily-imported OCCT WASM kernel still resolves once the package is inside someone else's node_modules.

Vendored modules

lib/ holds the tool logic — the same ES modules robosimtools.com serves at robosimtools.com/js/*.js. They are vendored (not fetched at runtime) so the package is self-contained. To refresh them from a local site checkout:

node scripts/sync-from-site.mjs /path/to/site/public/js

Design notes

• DOM in Node. Four tools (URDF validator, Xacro, MJCF, SDF converters) use the browser DOMParser/XMLSerializer. src/browser-globals.js provides those via linkedom so the modules run unchanged (its XMLSerializer strips the XML prolog linkedom adds, to match browsers).

• CAD kernel. robosim_step_to_urdf loads occt-import-js (a 7.6 MB WASM build of OpenCascade) lazily on first use.

• Plain JS ESM, zero build step.

Contributing

Bug reports and PRs are welcome — see CONTRIBUTING.md for scope, setup and the AI-assisted contribution policy (disclosure required). Security issues go through SECURITY.md, not the public issue tracker. Participation is governed by the Code of Conduct.

One thing worth knowing up front: lib/ is synced from robosimtools.com and PRs editing it directly will be closed — the next sync overwrites them. Report tool-logic bugs as issues here and they get fixed upstream, then synced down.

License

MIT © 2026 Rahul Rajelli. All code in src/ and lib/ is first-party.

The robosim_step_to_urdf tool depends on occt-import-js (a WASM build of Open CASCADE), which is LGPL-2.1. It is consumed unmodified as a separate npm dependency and loaded dynamically at runtime — no part of it is redistributed in this package. Full details, and the conditions a fork must preserve, are in THIRD-PARTY-NOTICES.md.