Creating a new category

A category is a profile: one YAML file under backend/app/profiles/data/, loaded and checked at startup. Nothing else changes when a profile is added; the model never edits one.

Write the file

# backend/app/profiles/data/hose_fitting.yaml
id: hose_fitting                 # must equal the file name
label: Hose fitting
description: >
  A push-fit or threaded fitting between a hose and a tap or a tool; the thread or the
  outer diameter decides fit.
features:
  - key: outer_diameter
    label: Outer diameter
    unit: mm
    tolerance_mm: 0.5
    how: >
      Photograph the fitting end-on with a ruler across it, straight on, and mark the two
      outer edges.
rules:
  - key: outer_diameter
    label: Outer diameter
    kind: within
    hard: true
    question: What is the outer diameter of the fitting, in millimetres?
  - key: thread
    label: Thread
    kind: equal
    hard: true
    identity: false
    question: What thread does it have, as printed on it or on its packaging?

Every key is described in the profile schema. A feature is a dimension worth measuring, with its tolerance and how to capture it; a rule is what a candidate is checked against, hard or soft, with the question to ask when the value is unknown. Rule keys may be feature keys, label fields or any other snake_case name a listing or an owner might supply.

Check it

./dev test backend

The loader refuses a file whose id differs from its name, a repeated rule key, a within rule without a tolerance, an equal rule with one, or a kind that is not one of the four, and says which. GET /api/profiles lists what loaded; GET /api/profiles/hose_fitting/rules shows the rules as the matcher reads them. In the web app the profile appears wherever one is chosen: on an item, on a search request, on the Does it fit? panel.

Use it

Set the profile on an item, measure its features, and the rules apply to any candidate: a listing brought back for a search, or another item. A project template that needs such a part names the profile in its requirement (profile: hose_fitting), so a missing requirement opens a search under it; see Build and reuse.

Not yet

A profile drafted by a model from a few example photos, for you to review before it is saved, is under Next steps.