Requirement
Reach for a card only when the card itself is the interaction — a unit the user clicks, selects, drags, or otherwise acts on as a whole (a project tile that opens a board, a selectable task, a draggable item). Static content — a settings section, a page intro, a read-only summary — is grouped with spacing, typography, and dividers, not with a border-radius-background box. The test: if removing the card chrome would not hurt comprehension, it should not be a card.
Rationale
Boxing everything in cards is the default AI composition, and it flattens hierarchy into a wall of equal-weight tiles where nothing leads. Card chrome is a signal — "this is a thing you can act on." When it is sprayed across static content the signal goes dead, the page reads as a template rather than a considered layout, and real interactive units no longer stand out. Whitespace, type scale, and a hairline divider group content more clearly and more quietly than a border ever does. This completes the harness's card trio: SLP-4 says do not nest cards, SLP-5 says do not lay them out as an identical grid, and SLP-11 asks the prior question — should this be a card at all? (HIG: Simplicity — let the structure come from the task, not from chrome.)
Passes when
- A grid of project tiles, each of which opens that project — the card is the click target.
- A list of selectable tasks where each row is a card you can pick or drag.
- A settings page whose sections are separated by headings, spacing, and dividers — no card boxes around read-only groups.
- A page intro and a read-only summary set apart by type scale and whitespace.
Fails when
- A static "About this page" blurb wrapped in a bordered, rounded, shaded box for no reason but visual separation.
- A form's sections each boxed in a card when a heading and spacing would group them.
- A dashboard where every region — interactive or not — is the same card, so nothing reads as more actionable than anything else.
Evaluator guidance
For each card-styled container in the screenshots, ask: is this a discrete thing the user acts on as a unit? If yes, it earns the card. If it is static content that card chrome only separates visually, it is a finding — recommend grouping with spacing, type, and dividers instead.
Do not flag:
- A container that is the interaction (clickable/selectable/draggable) — that is the correct use.
- An established, deliberate card pattern already shipped on the surface — the conservative-defaults rule (design Phase 4) presumes settled layout intentional; do not restyle it as a side effect. Raise it as a proposed change with rationale, never silently.
- A single content container used to set a focused task apart from page chrome, where it genuinely aids comprehension.
This is L2: a reasoned deviation (a platform pattern, a deliberate emphasis the team
tested) takes an inline dx-waive SLP-11 reason="…". "Looks more designed" is not a
reason.