Johnny.Decimal taxonomy

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The opinion

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The starter tree

areas:
  - start: 10, end: 19, name: Life admin
    categories:
      - { code: 11, name: Identity }
      - { code: 12, name: Health }
      - { code: 13, name: Education }
      - { code: 14, name: Vehicles }
      - { code: 15, name: Membership & subscriptions }

  - start: 20, end: 29, name: Money
    categories:
      - { code: 21, name: Banking }
      - { code: 22, name: Tax }
      - { code: 23, name: Insurance }
      - { code: 24, name: Investments }
      - { code: 25, name: Salary & benefits }

  - start: 30, end: 39, name: Home
    categories:
      - { code: 31, name: Utilities }
      - { code: 32, name: Rent & mortgage }
      - { code: 33, name: Purchases & warranties }
      - { code: 34, name: Repairs & maintenance }

  - start: 40, end: 49, name: System
    categories:
      - { code: 41, name: Templates }
      - { code: 42, name: Archive notes }
      - { code: 49, name: Inbox }    # system category — undeletable

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Invariants

• Every document has a jd_category_id — schema NOT NULL.
• The inbox category (system=1) is undeletable via API/UI.
• settings.jd_inbox_category_id always points at a live system category. If pruned, suchi repairs the pointer at boot and logs jd.inbox.repaired.
• Category codes are unique. Ranges nest exactly: category 22 must live inside an area 20..29.

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Over the JSON API

• GET /api/jd/categories/ — enumerate the tree. Query params: ?q=<prefix> (case-insensitive code-or-name match, ?q=22 and ?q=tax both hit 22 Tax), ?area=<code> (scope to one area’s 10-slot range). Each row carries area_code + area_name denormalized, so a picker can render the grouped tree in a single request. See api#get-apijdcategories.
• GET /api/documents/{id} — the JD fields on the response are denormalized: jd_category_id, jd_category_code, jd_category_name, jd_area_name. Enough to render “22 Tax · Money” without a second call. Set the category by PATCHing back with {"jd_category_id": <n>}.

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What the inbox is for