gen git:20261013.ce7c6ccA

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---
name: gen
description: Generate PartCAD geometry from a description, automatically deciding whether the request is a single part, a multi-part assembly, or a 2D sketch and following the matching flow. Use for /pc:gen or when the user asks to generate, create, or model something in PartCAD without saying whether it is a part, an assembly, or a sketch.
---

# pc:gen

Entry point for PartCAD generation when the user has not said whether they want a
single **part**, an **assembly**, or a 2D **sketch**. The text after the command
(`$ARGUMENTS`) is the description of what to build. Decide which it is, tell the
user your choice, then follow that flow — passing the same description through.

## Decide: part, assembly, or sketch?

- **Part** → `/pc:gen-part`. One continuous piece of 3D geometry — a bracket, a
  gear, a housing, a knob. Modeled as a single script, even when intricate.
- **Assembly** → `/pc:gen-assembly`. Several distinct 3D components that fit or
  move relative to each other — a gearbox, a robot arm, a body with a lid,
  anything joined by fasteners.
- **Sketch** → `/pc:gen-sketch`. A 2D profile, outline, or blueprint — a gasket
  shape, a plate outline, a cross-section to be extruded later.

Heuristics:

- "2D", "profile", "outline", "sketch", "cross-section", "blueprint" → **sketch**.
- One noun, "a"/"single", one manufacturing process, one printed/machined piece
  → **part**.
- Plurals, "with", "attached to", "... and a ...", moving joints, fasteners, or
  named sub-components → **assembly**.

If it is genuinely ambiguous, ask one short question. Otherwise proceed with your
best judgment and state which you picked — the user can redirect.

A physical claim in the description — it stands, it does not tip, it floats, it
holds a load, it works under water or on the Moon — is part of the request, not
decoration: carry it into the part or assembly flow, which makes the result
ready to simulate and checks the claim with `pc sim`.

## Then

- Sketch → follow **`/pc:gen-sketch`**.
- Part → follow **`/pc:gen-part`**.
- Assembly → follow **`/pc:gen-assembly`** (which itself uses `/pc:gen-part` for
  any missing components).

The part and the assembly flows write down what the object is required to be
as its `requirements:` before judging the result against them, and
`/pc:validate` gives a verdict on every one of them afterwards.