Text-to-CAD: make a dimensioned part you can inspect and revise

What the documentation establishes

The project documents local generation of STEP, GLB, STL and 3MF files through an agent plugin or skills. Source ↗

The README requires uv, recommends the latest release branch for installation, and calls for restarting the client. Source ↗

The CAD reference keeps editable Python model source separate from saved exports and includes geometry inspection workflows. Source ↗

The walkthrough below is an original worked exercise. We have not independently tested this product’s performance.

1. Define a part whose mistakes you can see

Imagine a small label plate on your desk. The first version is a flat 80 × 30 × 3 millimetre rectangle with two 4 mm through-holes. For this exercise, use sharp external corners and no lettering. Decorative details make early failures harder to diagnose and add decisions that are irrelevant to checking dimensions.

Set the origin at the lower-left corner of the bottom face. Width follows positive X, height positive Y, and thickness positive Z. Place the hole centres at (8, 15) and (72, 15) millimetres. These are fictional training dimensions. They are not a specification for attaching equipment, carrying a load, or fitting a particular fastener.

2. Install one supported path and record it

The README requires uv and a network connection for the initial CAD runtime download. For Claude Code, the project documents the commands below and a client restart. Use the release branch named latest; installing both the plugin and a separate copy of its skills can create duplicate instructions. Consult the current project page if your client is different.

Before you start the design, record your agent version, installed plugin revision, operating system, and the date. Ask the agent to report which installed CAD instructions it is using. If installation fails, retain the diagnostic message and fix that problem before requesting geometry. Repeatedly rephrasing a design will not repair a missing runtime.

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

3. Give the agent an output contract

Create an empty project folder for this exercise. Save the prompt as a brief before asking the agent to work. Require the editable model source, not only a mesh or screenshot. The expected first response is a restatement of the dimensions and the files it plans to create. Correct an incorrect origin or hole placement before it propagates into exports.

The project’s CAD instructions describe a Python model that returns geometry and saves STEP output. Ask the installed skill to choose the current APIs and exact regeneration command. Avoid copying an old generated script into a newer runtime without checking that contract. Our file names below are a suggested handoff layout, not mandatory plugin paths.

Create a new CAD project for a fictional desk-label plate.
Use the installed text-to-cad CAD skill and millimetres.
Origin: lower-left of the bottom face. X=width, Y=height, Z=thickness.
Version 1: width=80, height=30, thickness=3.
Two holes: diameter=4, centres=(8,15) and (72,15), through Z.
No lettering, chamfers, rounded corners, hardware or extra bodies.

Deliver:
- editable source with named dimensions;
- a STEP file and a separate STL export;
- a top view and an angled inspection view;
- the exact command that regenerates these outputs;
- a measurement table: requested / measured / method / pass or fail.
Use measured geometry for the measured column, not this prompt.
Mark an unmeasured property as unknown. Do not order or print anything.
Keep assumptions and failures in a short review note.

4. Inspect the saved files, not just the conversation

Open the exported STEP file in your viewer. Reset the view and orient it from above. Measure the outside dimensions, the diameter of each bore, and the centre positions. Turn the part over and look for a hole that stops short of the bottom. A circular mark in a top view does not prove a through-hole exists.

Open the STL separately. Confirm that the receiving application interprets its dimensions in millimetres; record that setting in the handoff. Compare its overall size with the STEP file and inspect the bores at a useful zoom level. If a mesh looks coarse, first decide whether this is display tessellation or the exported geometry. Do not accept a smoother screenshot as evidence of a corrected file.

A second independent check is the nominal volume. The rectangular volume is 80 × 30 × 3 = 7,200 mm³. Subtract two cylinders of radius 2 and height 3: the target is 7,200 − 24π, about 7,124.602 mm³. This arithmetic comes from our fictional brief. Agreement within a declared numerical tolerance can catch missing holes or unit mistakes, but cannot prove that the holes are in the right places.

Part: plate-v1
File opened: <exact STEP file>
Source revision: <commit or saved snapshot>
Viewer / version: <fill in>
Units: <observed import setting>
Bounds measured: <X, Y, Z>
Hole centres measured: <left>, <right>
Hole diameters measured: <left>, <right>
Nominal volume: 7200 - 24*pi mm^3
Measured volume / tolerance / method: <fill in>
Open questions: <anything not measured>
Result: <pass / revise / blocked>

5. Change one requirement and check the consequences

Keep version 1 before making a second version. Change the width to 100 mm while preserving the 8 mm inset from each short edge. The right hole must move to X=92; the left remains at X=8. Height, thickness, diameter, and Y positions stay unchanged. This small edit exposes whether the model is parameterized or merely a convincing one-off shape.

Tell the agent to regenerate exports from the source, then reopen the new files. The expected centre-to-centre spacing changes from 64 to 84 mm. Nominal volume becomes 9,000 − 24π, about 8,924.602 mm³. A width change with the right hole still at 72 mm fails even if the image looks reasonable. Check both versions and keep their measurement records distinct.

Create plate-v2 from the editable v1 source.
Change only width to 100 mm. Keep both hole centres 8 mm from
their nearest short edge and centred along Y. Preserve all other values.
Before generating, list the new hole coordinates and predicted volume.
Regenerate STEP and STL; measure the saved outputs again.
Keep v1 source, files and review notes intact.

6. Repair the smallest identifiable failure

Keep the failing output as evidence. Ask for one focused correction and name the property that should change. Re-run the full acceptance card after the fix: repairing a hole can accidentally alter thickness or leave an extra solid. When the runtime reports a kernel error, retain that error and reduce the geometry until you have a small reproducible problem. Do not silently drop the failing feature just to obtain an export.

7. Finish with a usable handoff and a clear next experiment

Package the two briefs, editable source, exact regeneration command, STEP and STL files, measurement notes, and two inspection images. Add a short change log: width increased, right hole moved, unchanged properties rechecked. A recipient should be able to identify which source produced each file without opening your chat history.

The next sensible exercise is a rounded corner or an engraved label, changing one feature at a time. Physical fabrication is a separate review: material, process, fit, tolerances, and the intended use all matter. This tutorial establishes a way to check a digital part. It does not establish print success or mechanical suitability.

Judge the tool by total work saved: time to describe, generate, inspect, correct, and hand off. Record how many changes survived regeneration without manual repair. If measuring the result takes longer than drawing this simple shape yourself, reserve the agent for a different kind of task. Keep the same acceptance card when comparing tools so attractive renders do not dominate the decision.

Guide history

Revisions preserve the original instructions. A source recheck alone does not create a new revision.

Revision 1 · New documented CAD workflow with an original dimensioned plate, independent geometry checks, controlled revision, troubleshooting and handoff. No plugin or fabrication test claimed.

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