urdf skill (earthtojake) for Claude Code: write and validate URDF robot descriptions

Makes Claude write and validate URDF robot descriptions: links, joints, limits, inertials and meshes.

Installs: 11.3K; on skills.sh
Stars: 24.7K; on GitHub
Files: 10; besides SKILL.md
Updated: Nov 2026; last repo commit

urdf makes Claude author URDF XML directly, record a design ledger of frames, joints, units and assumptions at the top of the file, validate with cad urdf validate and show the model in a viewer. Its description covers links, joints, limits, inertials, visual and collision geometry, mesh references and frame conventions.

It is part of text-to-cad and needs the cad command from the text-to-cad installer. SKILL.md says to compute inertia tensors and other derived numbers with formulas or a throwaway helper script, never by hand. It does not cover MoveIt semantic groups, which belong to the SRDF skill.

Good for

Robotics developers writing URDF for ROS, RViz or simulators
Engineers fixing frame, axis or mesh scale mistakes in a robot file
Anyone turning CAD meshes into a robot description

Install urdf

Claude Code

Copy this prompt.

Install the urdf skill in Claude Code. Run this command:

claude plugin marketplace add earthtojake/text-to-cad#latest
claude plugin install text-to-cad@earthtojake

Then check that it loaded and tell me how to use it.

2
Paste it into Claude Code. It shows the change and asks before running it.

Requires uv.

The skill runs a cad command. The plugin and the installer both set it up; a skills-only install needs the installer too.

From the project README. Source.

What's in the skill

When it loads

URDF robot description authoring and validation. Use when creating, editing, inspecting, validating, or debugging `.urdf` files, robot links, joints, limits, inertials, visual/collision geometry, mesh references, frame conventions, or robot-description artifacts. Use the SRDF skill for MoveIt2 semantic groups and IK/path-planning semantics; use the CAD skill for STEP/STL/3MF/DXF/GLB outputs. Open and visually review existing URDF files in CAD Viewer.

Sections in SKILL.md

Setup
Core Rules
Show the model
Workflow
Commands
Snapshot Tool
References

Key facts

Author: earthtojake (text-to-cad)
Repository: earthtojake/text-to-cad
License: MIT
Part of: text-to-cad (12 skills in the repo)
Needs: The cad command from text-to-cad, installed by its script
Installs on skills.sh: 11,281 (Nov 2, 2026)
GitHub stars (repo): 24,721 (Nov 2, 2026)
Last repo commit: Nov 1, 2026
Files: 10 files including SKILL.md (7 reference files, LICENSE, agents/openai.yaml)

What it includes

Runs the cad command, and runs the text-to-cad install script if cad is missing.
Install is curl -fsSL https://texttocad.dev/install.sh | sh, or irm ... | iex on Windows.
Runs code · Setup
The .urdf is the source of truth, keep a ledger, exact frame semantics, compute numbers.
Core rules (8)
A comment block at the top of the .urdf with frames, joints, geometry, units.
Write · Design ledger
One mesh per link, exported in that link's frame, before the URDF is written.
Mesh preparation
Closed-form formulas for primitives, or a helper script for mesh-derived values.
SKILL.md allows throwaway helper scripts for computed numbers.
Runs code · Inertials
Checks XML, tree, joints, geometry, meshes, materials and inertial physics.
Options are --strict, --json and --packages NAME=PATH for package:// meshes.
Runs code · cad urdf validate
Draws the robot to a PNG still with optional joint poses.
Writes the PNG path you give it, for example review.png.
Runs code · cad snapshot
Opens the CAD viewer and checks every movable joint against the ledger.
Runs code · Show the model and sweep joints
Find the target, ledger, meshes, author, compute, validate, verify, report.
Workflow (8 steps)
Authoring contract, ledger, frames, meshes, inertials, workflow and validation.
References (7)

From the official docs

Permissions

Medium risk

The skill holds instructions, but its setup runs an install script that changes your agent apps and starts a local server. Read the script or run it with --dry-run first.

What it can do

Read your data
Create and change things
Delete things
Read-only mode

Watch out for

Setup runs an install script from the internet
The skill's Setup section tells Claude to run curl -fsSL https://texttocad.dev/install.sh | sh if cad is missing. Per the install docs it installs uv, downloads the CAD runtime and sets up every agent app it finds. Run it with --dry-run first. github.com
It edits your agent apps' plugin setup
The installer adds the plugin or skills to each agent app it finds and keeps a receipt. The --uninstall option undoes what the receipt records. github.com
The plugin starts a local server
The plugin brings CAD's viewer, a local server (cad-mcp) that runs through uvx. cad viewer opens models in your browser. github.com
Usage stats and crash reports are on by default
The README says they carry a random ID and never include your files, paths or prompts. Add --no-telemetry to the installer to turn them off. github.com

Technical details

Talks to	texttocad.dev (install script). The CAD release and Python 3.14, downloaded by uv on first run. Usage stats and crash reports (host not named; see the privacy policy)

Questions

How do I install the urdf skill?

Use the install box above. The skill needs the cad command, which comes from the text-to-cad plugin or installer. A skills-only install also needs the installer. Python 3.14 is managed by uv.

Do I need ROS?

The validation reference lists check_urdf from ROS as an external check to run when installed, and to report as skipped when unavailable.

urdf vs sdf vs srdf?

All three are separate skills in text-to-cad. The urdf description says it covers the robot's structure, not MoveIt2 semantic groups (SRDF). The sdf skill covers simulator models and worlds, and derives from an existing URDF.

Does validation prove the robot is correct?

No. SKILL.md says a URDF can pass every structural check and still place a joint in the wrong spot, which is why it asks for the ledger and a viewer sweep of every joint.

Does it send my data anywhere?

The README says text-to-cad sends usage stats and crash reports by default, tagged with a random ID and never including your files, paths or prompts. The installer has a --no-telemetry option.

Is it safe to install?

The skill folder has Markdown, a LICENSE and a small agents/openai.yaml, and no script files. The setup runs an install script and starts a local server, which the permissions section describes.

What mesh formats can the snapshot draw?

SKILL.md says STL, 3MF and GLB, plus box, cylinder and sphere shapes. It refuses .dae and .obj meshes by name.

Information

updated Nov 2, 2026

Repository: earthtojake/text-to-cad
Folder: skills/urdf

earthtojake/text-to-cad skills.sh

Sources

Docs, issue trackers and discussions this page is built from.

Show all 7

text-to-cad README · github.com
Installing text-to-cad by hand · github.com
SKILL.md · github.com
skills.sh listing · skills.sh
Repository · github.com
sdf SKILL.md · github.com
urdf validation.md · github.com