animate— agent skill

Analyze a feature and strategically add animations and micro-interactions that enhance understanding, provide feedback, and create delight.

MANDATORY PREPARATION

Context Gathering (Do This First)

You cannot do a great job without having necessary context, such as target audience (critical), desired use-cases (critical), brand personality/tone (playful vs serious, energetic vs calm), and performance constraints.

Attempt to gather these from the current thread or codebase.

1. If you don't find exact information and have to infer from existing design and functionality, you MUST STOP and STOP and call the AskUserQuestionTool to clarify. whether you got it right.
2. Otherwise, if you can't fully infer or your level of confidence is medium or lower, you MUST STOP and call the AskUserQuestionTool to clarify. clarifying questions first to complete your context.

Do NOT proceed until you have answers. Guessing leads to inappropriate or excessive animation.

Use frontend-design skill

Use the frontend-design skill for design principles and anti-patterns. Do NOT proceed until it has executed and you know all DO's and DON'Ts.

Assess Animation Opportunities

Analyze where motion would improve the experience:

1. Identify static areas:

• Missing feedback: Actions without visual acknowledgment (button clicks, form submission, etc.)
• Jarring transitions: Instant state changes that feel abrupt (show/hide, page loads, route changes)
• Unclear relationships: Spatial or hierarchical relationships that aren't obvious
• Lack of delight: Functional but joyless interactions
• Missed guidance: Opportunities to direct attention or explain behavior

1. Understand the context:

• What's the personality? (Playful vs serious, energetic vs calm)
• What's the performance budget? (Mobile-first? Complex page?)
• Who's the audience? (Motion-sensitive users? Power users who want speed?)
• What matters most? (One hero animation vs many micro-interactions?)

If any of these are unclear from the codebase, STOP and call the AskUserQuestionTool to clarify.

CRITICAL: Respect prefers-reduced-motion. Always provide non-animated alternatives for users who need them.

Plan Animation Strategy

Create a purposeful animation plan:

• Hero moment: What's the ONE signature animation? (Page load? Hero section? Key interaction?)
• Feedback layer: Which interactions need acknowledgment?
• Transition layer: Which state changes need smoothing?
• Delight layer: Where can we surprise and delight?

IMPORTANT: One well-orchestrated experience beats scattered animations everywhere. Focus on high-impact moments.

Implement Animations

Add motion systematically across these categories:

Entrance Animations

• Page load choreography: Stagger element reveals (100-150ms delays), fade + slide combinations
• Hero section: Dramatic entrance for primary content (scale, parallax, or creative effects)
• Content reveals: Scroll-triggered animations using intersection observer
• Modal/drawer entry: Smooth slide + fade, backdrop fade, focus management

Micro-interactions

• Button feedback:
• Hover: Subtle scale (1.02-1.05), color shift, shadow increase
• Click: Quick scale down then up (0.95 → 1), ripple effect
• Loading: Spinner or pulse state
• Form interactions:
• Input focus: Border color transition, slight scale or glow
• Validation: Shake on error, check mark on success, smooth color transitions
• Toggle switches: Smooth slide + color transition (200-300ms)
• Checkboxes/radio: Check mark animation, ripple effect
• Like/favorite: Scale + rotation, particle effects, color transition

State Transitions

• Show/hide: Fade + slide (not instant), appropriate timing (200-300ms)
• Expand/collapse: Height transition with overflow handling, icon rotation
• Loading states: Skeleton screen fades, spinner animations, progress bars
• Success/error: Color transitions, icon animations, gentle scale pulse
• Enable/disable: Opacity transitions, cursor changes

Navigation & Flow

• Page transitions: Crossfade between routes, shared element transitions
• Tab switching: Slide indicator, content fade/slide
• Carousel/slider: Smooth transforms, snap points, momentum
• Scroll effects: Parallax layers, sticky headers with state changes, scroll progress indicators

Feedback & Guidance

• Hover hints: Tooltip fade-ins, cursor changes, element highlights
• Drag & drop: Lift effect (shadow + scale), drop zone highlights, smooth repositioning
• Copy/paste: Brief highlight flash on paste, "copied" confirmation
• Focus flow: Highlight path through form or workflow

Delight Moments

• Empty states: Subtle floating animations on illustrations
• Completed actions: Confetti, check mark flourish, success celebrations
• Easter eggs: Hidden interactions for discovery
• Contextual animation: Weather effects, time-of-day themes, seasonal touches

Technical Implementation

Use appropriate techniques for each animation:

Timing & Easing

Durations by purpose:

• 100-150ms: Instant feedback (button press, toggle)
• 200-300ms: State changes (hover, menu open)
• 300-500ms: Layout changes (accordion, modal)
• 500-800ms: Entrance animations (page load)

Easing curves (use these, not CSS defaults):

/* Recommended - natural deceleration */
--ease-out-quart: cubic-bezier(0.25, 1, 0.5, 1);    /* Smooth, refined */
--ease-out-quint: cubic-bezier(0.22, 1, 0.36, 1);   /* Slightly snappier */
--ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);     /* Confident, decisive */

/* AVOID - feel dated and tacky */
/* bounce: cubic-bezier(0.34, 1.56, 0.64, 1); */
/* elastic: cubic-bezier(0.68, -0.6, 0.32, 1.6); */

Exit animations are faster than entrances. Use ~75% of enter duration.

CSS Animations

/* Prefer for simple, declarative animations */
- transitions for state changes
- @keyframes for complex sequences
- transform + opacity only (GPU-accelerated)

JavaScript Animation

/* Use for complex, interactive animations */
- Web Animations API for programmatic control
- Framer Motion for React
- GSAP for complex sequences

Performance

• GPU acceleration: Use transform and opacity, avoid layout properties
• will-change: Add sparingly for known expensive animations
• Reduce paint: Minimize repaints, use contain where appropriate
• Monitor FPS: Ensure 60fps on target devices

Accessibility

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

NEVER:

• Use bounce or elastic easing curves—they feel dated and draw attention to the animation itself
• Animate layout properties (width, height, top, left)—use transform instead
• Use durations over 500ms for feedback—it feels laggy
• Animate without purpose—every animation needs a reason
• Ignore prefers-reduced-motion—this is an accessibility violation
• Animate everything—animation fatigue makes interfaces feel exhausting
• Block interaction during animations unless intentional

Verify Quality

Test animations thoroughly:

• Smooth at 60fps: No jank on target devices
• Feels natural: Easing curves feel organic, not robotic
• Appropriate timing: Not too fast (jarring) or too slow (laggy)
• Reduced motion works: Animations disabled or simplified appropriately
• Doesn't block: Users can interact during/after animations
• Adds value: Makes interface clearer or more delightful

Remember: Motion should enhance understanding and provide feedback, not just add decoration. Animate with purpose, respect performance constraints, and always consider accessibility. Great animation is invisible - it just makes everything feel right.