cad

SKILL.md

CAD generation, inspection, and validation

Provenance: maintained in earthtojake/text-to-cad.
Use the installed local skill files as the runtime source of truth; the
repository link is only for provenance and release review.

Purpose

Create or modify parametric CAD models from natural-language requirements, generate validated STEP/STP artifacts, inspect geometry references, and return checked outputs. Treat STEP as the primary CAD artifact. Treat STL, 3MF, and native GLB as secondary export workflows that branch from a STEP-first process. For assemblies, prefer cadpy.assembly.AssemblyHelper with source-level build123d joints, named mating datums, and native labels when the parts have functional assembly relationships.

There are two ways into the STEP workflow: generate from build123d Python source (the default when designing from scratch or modifying a generated model), or import an existing STEP/STP file directly (when no generator exists or the user explicitly targets the STEP file). Both produce the same inspectable artifacts.

Use this skill when

Use this skill when the user asks for CAD files, STEP/STP files, build123d source, selector refs such as #o1.2.f1, mechanical parts, assemblies, enclosures, brackets, fixtures, holes, counterbores, countersinks, slots, pockets, bosses, standoffs, ribs, fillets, chamfers, shells, source-level joints, mating, or measurements. Also use it when the user supplies reference images or 2D technical drawings of a part to reproduce or take design intent from.

Also use it when the user asks for STL, 3MF, or native GLB output from CAD geometry. Keep those workflows secondary and load supported-exports.md for details. For 2D DXF drawings, use the $dxf skill; when a DXF projects from a 3D part, this skill owns the STEP geometry and $dxf owns the drawing.

Do not use this skill for render-only concept art, CAM toolpaths, engineering certification, FEA conclusions, architectural BIM, or freehand illustration unless the user also needs CAD geometry.