P291 · Output contracts

Label implementation approximation provenance

Distinguish an official implementation from an inspired approximation.

Editorially reviewed

These examples and illustrative results are independently authored teaching materials, not measured model results.

Use case

A web card needs a look inspired by a native translucent material. The teaching implementation uses custom CSS blur, borders and highlights, with no official platform package. Similar appearance does not make the code official.

Mechanism

Determine whether the brief requires visual inspiration or a specific official system. For an official requirement, verify platform scope, authoritative dependency and contract, reporting gaps if unmet. For inspiration, label a web approximation and separate platform references from actual project code/dependencies. Provide a legible solid fallback, check target browsers and limit equivalence claims.

Bad example

Name the custom blur CSS an official native-material package and promise identical platform effects and behavior.

Good example

Describe this web card as an approximation inspired by native material. Record actual CSS, platform references and custom portions, provide a solid fallback and verify text legibility in target browsers. Label only genuinely official, contract-compliant portions official; verify present availability.

Why the change matters

Provenance tells the receiver who maintains dependencies and bears compatibility responsibility. Visual approximation and official interfaces carry different promises, affecting platform choices and maintenance.

Observable expectation

The teaching delivery says project CSS approximation and lists no invented official package. Disabling blur remains readable. Check consistent provenance in README, comments and user-facing explanation; a platform citation is not proof of using its implementation.

Limits

Frozen platform/package availability is not a present fact. Approximations can differ in performance, accessibility and interaction, and provenance labels do not establish quality. Handle branding, licensing and dependencies under actual asset contracts.

Sources and evidence

Read the editorial criteria