cad skill for Claude Code: design 3D CAD parts as Python scripts

Makes your agent design 3D CAD parts and assemblies as Python scripts and show them live in a CAD viewer.

Installs: 14.9K; on skills.sh
Stars: 24.7K; on GitHub
Files: 13; besides SKILL.md
Updated: Nov 2026; last repo commit

The cad skill tells your agent to write each part or assembly as a Python function using build123d, run it with the cad command, and hand you a link to a viewer page that updates on every rebuild. STEP, STL, 3MF, GLB and xbf files are written only when you ask for them.

It triggers on 3D CAD modeling, edits to a model script, project layout, exports, mechanisms, and explode or showcase animations. It needs the text-to-cad installation, which provides the cad command and a local server. The skill folder does not contain them, so follow the install box.

It covers 3D parts and assemblies. The SKILL.md leaves out the 2D DXF drawing and URDF, SRDF and SDF robot files; the text-to-cad README lists separate skills for those.

Good for

Makers designing parts they plan to 3D print or machine
Engineers who want parametric models kept as code
Anyone who needs STEP, STL, 3MF or GLB files from a plain-language request
People who want to open and check an existing STEP, STL, 3MF, GLB or XBF file

Install cad

Claude Code

Copy this prompt.

Install the cad 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, Claude Code.

The plugin brings all 12 skills in the text-to-cad repo, including cad, and starts the cad MCP server through uvx (pinned to cad-mcp 0.10.0). It has no hooks or agents. Its first start downloads CAD's runtime, so it needs a network connection. docs/install.md says to install the plugin or the skills in an app, not both. The installer script is the fallback: it sets text-to-cad up in every agent app on the machine. By default text-to-cad sends usage stats and crash reports tagged with a random ID, never your files, paths or prompts (README); the installer takes --no-telemetry.

From the vendor's docs. Source.

What's in the skill

When it loads

Creates and edits parametric CAD parts and assemblies as Python build123d models that cadgen's engine builds and the CAD Viewer shows live; exports STEP, STL, 3MF, GLB and xbf files on request; resolves prompt references, measures geometry, and articulates or animates assemblies. Use for 3D CAD modeling, editing a model script (any change to a part's or assembly's `.py`), organizing a CAD project, exporting or converting CAD files, Quick Edit prompts, mechanisms, and explode or showcase animations. Opens and reviews existing XBF, STEP/STP, STL, 3MF and GLB files in the CAD Viewer.

Sections in SKILL.md

Start with the task
Setup and paths
Write a model and run it
Files, when asked
Projects built around exported files
Pictures
Prompt references and inspection
Check the design
Hand off
Show the model

Key facts

Author: earthtojake (repo owner; the README names text-to-cad as the project)
Repo: earthtojake/text-to-cad, folder skills/cad
Installs on skills.sh: 14,933 as of 2 Nov 2026
GitHub stars: 24,721 for the whole earthtojake/text-to-cad repo, 2 Nov 2026
License: MIT (LICENSE file in the skill folder and the SKILL.md frontmatter)
Last commit in the repo: 2026-11-01
What is inside: 12 files including SKILL.md: 9 reference guides, an agents/openai.yaml and a LICENSE; no scripts
skills.sh audits: Gen Agent Trust Hub pass, Socket pass, Snyk pass
Works in: The README says any agent that supports plugins or skills, including Claude Code, Codex, Cursor, Gemini and Grok
Needs: The text-to-cad install (the cad command and its server); uv, which the installer adds if missing

What it includes

Builds a model script and prints a viewer link
Runs the model script in text-to-cad's local server. The output shows how the model built, its size, and a `view:` link that follows every later run.
Try: “Make a mounting bracket, 40 mm wide, 6 mm thick, with an 8 mm hole, and show it to me.”
Runs code · cad run <script>
A part is a Python function with the @model decorator
The agent writes the part or assembly as a build123d function. An assembly calls its parts and returns them combined. Units are millimetres, +Z is up.
Write · Model scripts
Writes STEP, STL, 3MF, GLB or xbf files when asked
Exports are an action on the built model, not part of it. A project with standing deliverables gets an exports.py that rewrites them all.
Try: “Export the bracket as STEP and STL.”
Write · cad export
Resolves a face, edge or part reference to measured facts
When your prompt names a reference copied from the viewer, the agent resolves it to JSON with area, length, volume and the line of code that made it.
Read · cad inspect
Draws a PNG of a model, view or pose
Used to judge a structural or appearance change. Options include camera angle, display style and a named pose. It shows arrangement, not dimensions.
Try: “Show me the bracket from the top with hidden lines.”
Write · cad snapshot
Measures fits, clearances and mass with Python
Written only when you ask for a dimension, a fit or a mass. The agent measures what the model returns instead of reading numbers off a picture.
Runs code · Check scripts
Mechanisms with build123d joints, plus explode or showcase animations
Articulated assemblies use joints in the model body. Explode, reveal and showcase animations use an animation() call in the body.
Write · Joints and animation
Opens a model or an existing file in the CAD Viewer
Gives you a link to the viewer page. It opens XBF, STEP/STP, STL, 3MF and GLB files you already have.
Runs code · cad viewer / cad_show
Installs, diagnoses and stops the local server
If cad is not found, the SKILL.md tells the agent to run the text-to-cad installer script. cad doctor explains the installation and cad stop stops the server.
Runs code · Installer, cad doctor, cad status, cad stop

From the official docs

Permissions

Medium risk

What it can do

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

Watch out for

It can run a piped install script
If `cad` is not found, the SKILL.md tells the agent to run the installer from texttocad.dev, outside a sandbox or with its permission. Read the script first, or install text-to-cad yourself. github.com
The installer changes every agent app on your computer
The README says it sets up text-to-cad in every agent app it finds, installs uv if missing, and moves the server to the new release. Run it only on a machine where that is fine. github.com
The installer adds a plugin with an MCP server and edits Claude Desktop config
Per the README, the installer sets up the plugin, which brings the skills and CAD's MCP server, in each agent app it finds. docs/install.md says Claude Desktop's config gets CAD's server, with a .bak of the file kept, and that it can run with --dry-run to print the plan first. github.com
Usage stats and crash reports are on by default
The README says text-to-cad sends usage stats and crash reports tagged with a random ID, and that they never include your files, paths or prompts. Its privacy policy says what is sent and how to turn it off. docs/install.md shows the installer option --no-telemetry. github.com
The plugin starts a local cad MCP server
The Claude Code, Codex and Cursor plugins start a `cad` MCP server through uvx, pinned to cad-mcp 0.10.0 (per docs/install.md). On first start it downloads CAD's runtime and builds the environment models run in, which can take a while and needs a network connection. It runs on your machine, and the plugin has no hooks or agents. Skip the plugin and use the skills alone if you do not want a server. github.com
Model scripts can install Python packages
`cad run` installs packages named in a script's dependencies block into an environment it keeps. Read that block before the agent runs a script you did not write. github.com
A local server keeps running
One server runs for the installation and serves the viewer. Its links carry a token, so do not share them. `cad stop` stops the server. github.com

Technical details

Turning on read-only	The SKILL.md defines no read-only switch.
Talks to	texttocad.dev (installer script, when cad is not found). Python package downloads when a model script lists dependencies. text-to-cad usage stats and crash reports, unless telemetry is turned off. uvx downloads cad-mcp and CAD's runtime on the plugin's first start (PyPI)
Scopes	Runs the cad command and model scripts in text-to-cad's local server Writes exports you ask for (STEP, STL, 3MF, GLB, xbf) and PNG snapshots such as tmp/review.png Reads files a model opens, such as vendor STEP, xbf or mesh files With the plugin, the cad MCP server (cad-mcp, started with uvx) serves CAD's viewer and tools locally

Questions

What does the cad skill do?

It makes your agent build 3D CAD parts and assemblies as Python build123d scripts, check them, and show them in a live viewer. It writes STEP, STL, 3MF, GLB or xbf files only when you ask.

How do I install the cad skill?

Use the install box on this page and start with the text-to-cad installer. The skill needs the cad command that the installer provides, so adding only the skill folder is not enough.

Does it work in Codex or Cursor?

The text-to-cad README says it is supported by all popular agents that support plugins or the skills framework, including Claude Code, Codex, Cursor, Gemini and Grok.

Does it need an API key?

Neither the SKILL.md nor the README lists one. The setup step is the installer script, and a model script can name extra Python packages that cad run installs.

Can it make 2D drawings or robot files?

Not this skill. Its SKILL.md excludes the 2D DXF drawing and URDF, SRDF and SDF robot descriptions. The README lists separate dxf, urdf, srdf, sdf and engineering-drawing skills in the same repo.

Is the cad skill safe to run?

It runs shell commands and Python on your machine, and it may run an install script if cad is missing. Read the install script before you run it, and review the dependencies line of any model script before the agent runs it. The Watch out list has the details.

Information

updated Nov 2, 2026

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

earthtojake/text-to-cad skills.sh

Sources

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

Show all 3

text-to-cad README · github.com
cad SKILL.md · github.com
text-to-cad install guide · github.com