Sibling contract

Motion

Motion is structural communication, not ornament. If motion files are malformed or violate the non-negotiable standards, they degrade trust, clarity, and usability.

Version 0.1.0 · provisional · machine export

Source authority

Primary standard

Lottie Animation Community Specification v1.0.1 (2025-06-26)

JSON Schema

https://lottie.github.io/lottie-spec/1.0.1/specs/schema/

Reference validator

ajv 8.20.0 (draft 2020-12 via ajv/dist/2020) + ajv-formats 3.0.1

Ten Non-Negotiable Motion Standards

01Easing is deliberateUse contract cubicBezier tokens, not bare CSS keywords

02Properties are explicitNever transition:all. Name exact properties.

03Entrances have opacityAnimate from scale(0.9-0.97) + opacity, never scale(0)

04Keyboard is stillNo motion on keyboard-initiated or high-frequency interactions

05Layout is not animatedNever animate width/height/margin/padding/top/left. Use transform/opacity.

06Touch is gated:hover motion on touch surfaces requires explicit gating

07Duration is boundedUI animation ≤ 300ms unless justified

08Reduced-motion is handledEvery animation has prefers-reduced-motion path

09Press is asymmetricPress and release use asymmetric timing

10Easing is never ease-inNo ease-in. Deceleration (ease-out) or custom curves only.

Verification — 10 checks

01m01 · Lottie file validates against LAC v1.0.1 JSON SchemaPASS: Schema valid · FAIL: Schema violation

02m02 · Required fields present (v, fr, ip, op, w, h, layers)PASS: All present · FAIL: Any missing

03m03 · No deprecated Bodymovin version (v: "4.x")PASS: v >= "5.x" · FAIL: v: "4.x"

04m04 · markers array present (reduced-motion support)PASS: Present · FAIL: Missing

05m05 · meta object present (attribution, author, description)PASS: Present · WARN: Missing (attribution gap)

06m06 · prefers-reduced-motion path documented (§3.4)PASS: Documented · FAIL: Not handled · WARN: External wrapper noted

07m07 · Easing uses deliberate curves (§16.1, §16.10)PASS: Custom curves · FAIL: ease/linear/ease-in

08m08 · Duration ≤ 300ms for UI motion (§16.7)PASS: <= 300ms · FAIL: > 300ms without justification

09m09 · No layout-property animation (§16.5)PASS: transform/opacity only · FAIL: width/height/margin/padding/top/left

10m10 · No motion on keyboard-initiated actions (§16.4)PASS: Still · FAIL: Motion on keyboard

10 checks. PASS=1, WARN=0.5, FAIL=0. Score = (points/10) × 100. A≥90, B≥80, C≥70, D≥60, F<60.

Open questions

Raw schema URL verification: is it lottie.schema.json appended to the schema path?
Reduced-motion marker convention: should Designesy establish "reduced"/"calm"/"static" name?
GSAP scope: should this contract cover GSAP timeline validation or a separate contract?
HyperFrames scope: does rule.atlas.hyperframes_quality_gate handle HyperFrames independently?
Lottie spec stability: should validator warn when file uses features outside approved subset?

Sibling contract to the design system v0.3.0. Machine export at /contracts/motion.json.