Free resource · ToolClaude CodeCodexOpen source

AI just killed mechanical engineering.

Someone open-sourced a Claude skill that turns plain English into full mechanical designs — moving parts, physics validation, animated assemblies. URDFs for robots. 4,100 stars on GitHub in a single week.

Install on cadskills.xyz How it works

4.1K GitHub stars in the first week · one-line install on any agent · open source, fully local.

install

# one line. works in claude code, codex, cursor.
$ npx skills add earthtojake/text-to-cad

# then, in your agent chat:
› design a 6-DOF robotic arm with mecanum wheels.
  export URDF + animated STEP. validate joint limits.

What it builds

Text in. Real hardware out.

Mechanism validation

Describe a gear train, linkage, or hinge in plain English. The agent generates parametric source, runs assembly + physics checks, and only ships if the mechanism actually moves.

STEP, STL, URDF — all of it

Export STEP for fab, STL for print, 3MF for slicers, DXF for laser, GLB for the web. Robotics? URDF, SRDF, SDF with joint limits and inertials, ready for sim.

Animated assemblies

Parameters become sliders. Assemblies become animations. Reference any face or feature with stable @cad[…] handles so the agent can edit precisely on follow-ups.

From the benchmark

Things people have already shipped.

Ten reference builds ship with the repo. Three that show the range — same one-prompt workflow for each.

Example 01

Planetary gear assembly

Sun + planets + ring, correct tooth count, animated rotation. One prompt — fully parametric STEP file you can drop straight into Fusion or send to print.

Example 02

Adjustable standing desk

Frame with linear actuators, joints constrained, weight + load checked. Generated as a working URDF you can simulate before cutting any metal.

Example 03

6-DOF robotic arm

Links, joints, inertials, MoveIt2 semantics. SRDF planning groups + end effector. Tested in sim, ready to bolt to your bench.

The stack · four tools

Everything you need, fully local.

AgentClaude Code / Codex

The model that writes the CAD source.

Skillscadskills.xyz

Open-source skill pack, install in one line.

Kernelbuild123d + OCP

Parametric Python CAD on OpenCascade.

ViewerCAD Explorer

Local browser preview — no backend, no login.

Setup · 6 steps

From zero to working STEP file.

You need an agent (Claude Code or Codex), Python 3.11+, and Node. Total time: about 5 minutes. If anything errors, paste it into the chat and let the agent fix itself — that's the whole workflow.

Pick your agent

The skills work with anything that speaks the agent-skills standard: Claude Code, Codex, Cursor, GitHub Copilot, Windsurf, Gemini, Cline. Pick whichever you already pay for. If you don't have one yet, Claude Code in VS Code is the easiest entry — see the content brain guide for the setup walkthrough.

Install Python 3.11+ and Node

The CAD kernel runs on Python (build123d + OpenCascade). The CAD Explorer viewer runs on Node. Quickest path:

# macOS — homebrew
brew install python@3.11 node

# windows — winget
winget install Python.Python.3.11 OpenJS.NodeJS

iAlready have these? Skip ahead. The skill installer will complain if anything's missing.

Install the skills

One line. Run this in any terminal — it adds the full text-to-cad skill pack to your agent:

$ npx skills add earthtojake/text-to-cad

Restart the agent if the skills don't show up immediately. You'll get seven skills: CAD, Render, step.parts, URDF, SRDF, SDF, SendCutSend — described in detail at cadskills.xyz.

Prompt your first part

Start a new folder, open it in your agent, and just ask. The skills handle the kernel calls — you only write English:

› design a planetary gear assembly.
  sun gear 12T, three planets, ring 40T.
  export STEP. animate the rotation.

The agent writes parametric Python, runs the kernel, drops a STEP file in the folder, and commits the source.

Inspect in CAD Explorer

The Render skill spins up a local viewer in your browser — no backend, no login. You see the part, scrub the animation, and copy stable @cad[…] handles for any face or feature.

Want to tweak? Paste the handle back into chat: "chamfer this edge by 0.5mm". The agent edits the source precisely — no more "the round one on the left".

Export, fab, repeat

Ship it:

3D print — ask for STL or 3MF, drop into your slicer.
Laser / waterjet — ask for DXF, run the SendCutSend skill for a preflight check.
Robotics sim — ask for URDF + SRDF, load into MoveIt2 or Gazebo.

+Pro move: commit the Python source and artifacts together. Next iteration is a one-line diff, not a CAD-history archaeology dig.

Where it lands

Three ways I'd use this today.

The skills cover the whole pipeline — prompt to part to fab. Three workflows that suddenly become realistic for solo builders.

Use 01

Hardware MVPs in a day

Iterate enclosures, brackets, jigs, and mounts the way you iterate code. Commit the source, regenerate STL, print, repeat.

Use 02

Robot URDFs without the pain

Skip the days of hand-writing joint trees. Describe the robot, let the SRDF/URDF skills wire the kinematics, then plug into ROS / MoveIt2.

Use 03

Send straight to fab

The SendCutSend skill runs a manufacturing preflight on your DXF/STEP files. Bend radii, hole spacing, material gotchas — caught before upload.

FAQ

Things people ask first.

Do I need to know CAD?

Not to start. You describe the part in English, the agent writes the parametric build123d source, and the viewer shows you the result. You only crack open the Python when you want surgical edits — by then you'll have read enough generated source to follow it.

Is it really free?

Yes — fully open source, MIT-licensed, runs locally on your machine. No backend, no subscription, no cloud fees. You pay only for the agent you already use (Claude Code or Codex).

Which agents work with it?

Claude Code, Cursor, Codex, GitHub Copilot, Windsurf, Gemini CLI, Cline — anything that supports agent skills. The same skill pack installs across all of them.

Can the output actually be manufactured?

That's the point. The CAD skill outputs source-controlled STEP, the SendCutSend skill checks DXF/STEP for sheet-metal gotchas, and the step.parts skill plugs in real off-the-shelf hardware (screws, bearings, motors) so the BOM matches reality.

Credit where it's due

text-to-cad is built and open-sourced by earthtojake. The skill pack and docs live at cadskills.xyz. I found it through the firehose and wrote this guide so you can ship with it the same day.

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Keep going

Stop sketching. Start prompting.

One line installs the skills. One prompt builds the part. The rest is iteration speed you've never had on hardware before.

Install on cadskills.xyz Star on GitHub