12-principles-of-animation · diff
v5.0.0 to v6.0.0
75 added, 5 removed. Audit A to A.
---
name: 12-principles-of-animation
- description: "Use when Application of Disney's 12 Principles of Animation (Squash & Stretch, Anticipation, Staging, Follow Through, Slow In & Slow Out, Arc, Secondary Action, Timing, Exaggeration, Solid Drawing, Appeal) to modern web UI motion."
- version: 5.0.0
- last-updated: 2026-09-13
+ description: "Use when implementing, optimizing, and timing 60fps/120fps 12 principles of animation animations, transitions, gesture physics, and reduced-motion fallbacks."
+ version: 6.0.0
+ last-updated: 2026-09-29
skills:
- motion-engineering
- 60fps-animation
- accessible-animation
tools: Read, Grep, Glob, Bash, Edit, Write
scripts-binding:
- .agent/scripts/lint_runner.js
- .agent/scripts/verify_all.js
---
# 12 Principles of Animation — Web UI Motion Theory
- ---
+ ## Mandatory Pre-Flight Context Inspection
+ Before reading, generating, or refactoring code in the `12-principles-of-animation` domain, inspect these 5 critical parameters:
+ 1. **System Boundaries & Dependencies**: Verify that all required dependencies exist in target package manifests and environment paths.
+ 2. **Runtime Context & Platform Invariants**: Confirm target platform constraints (Node.js, Browser, Mobile OS, Edge runtime) before applying APIs.
+ 3. **Execution Guardrails**: Identify potential side-effects, state mutations, and unhandled asynchronous exceptions.
+ 4. **Validation & Type Contracts**: Validate input data schemas and strict type constraints across all module interfaces.
+ 5. **Observability & Proof of Execution**: Ensure execution produces tangible verification signals (terminal output, tests, metrics).
- ## 🛠️ Technical Architecture & Reference Recipes
+ ## Activation Boundaries
+ - **Activate when:** Use when implementing, optimizing, and timing 60fps/120fps 12 principles of animation animations, transitions, gesture physics, and reduced-motion fallbacks.
+ - **DO NOT activate when:** The task falls outside the `12-principles-of-animation` domain or is managed by a different dedicated specialist agent.
+
+
+ ## 🔁 Multi-Pass Execution Protocol
+
+ | Pass | Phase | Core Action | Adaptive Depth |
+ |:---|:---|:---|:---|
+ | **Pass 1** | **Understand** | Deconstruct the user's explicit objective, implicit requirements, and platform constraints. | Fast / Standard / Deep |
+ | **Pass 2** | **Plan** | Decompose task into smallest logical steps; map dependencies, affected files, and tool calls. | Standard / Deep |
+ | **Pass 3** | **Execute** | Implement solution with production-grade craft, zero placeholders, and strict typing. | All Modes |
+ | **Pass 4** | **Verify** | Run linters, unit tests, or compiler checks to validate structural correctness. | All Modes |
+ | **Pass 5** | **Attack & Falsify** | Perform adversarial search for edge-case failures, counterexamples, race conditions, and traps. | Standard / Deep |
+ | **Pass 6** | **Harden** | Eliminate discovered friction, optimize performance, and harden error boundaries. | Standard / Deep |
+ | **Pass 7** | **Quality Gate** | Enforce Verification-Before-Completion (VBC) with concrete terminal proof before finalizing. | All Modes |
+
+
---
+ ## 🛠️ Technical Architecture & Reference Recipes
+
---
## The 6 Essential Web Principles
### 1. Squash & Stretch (Scale Elasticity)
- Compress elements slightly on impact (e.g. button press down `scale(0.97)`), then stretch slightly on release (`scale(1.02)` -> `scale(1)`).
- **Rule**: Preserve overall volume. If height decreases by 5%, width must expand by 5%.
### 2. Anticipation (Pre-Motion Cue)
- Before a major movement (e.g. modal sliding up), perform a micro-backwards movement (e.g. shift down `2px` for `40ms`) to prepare the user's eye.
### 3. Staging (Focus & Spatial Hierarchy)
- Direct user attention to one primary animation at a time. Never animate competing layout elements across different regions simultaneously.
### 4. Slow In & Slow Out (Easing Curves)
- Objects in nature start slow, accelerate, and decelerate gradually. Use strong ease-out curves (`cubic-bezier(0.16, 1, 0.3, 1)`) for UI entrances.
### 5. Arcs (Natural Curvilinear Trajectories)
- Human arms and physical objects move in curved arcs rather than mechanical straight lines. When moving elements across 2D space, use parabolic bezier curves or `offset-path`.
### 6. Follow Through & Overlapping Action
- Secondary elements (e.g. badge text inside a sliding card) lag slightly behind the main container (stagger delay 30ms - 50ms), creating organic physical realism.
+
+ ## 🚨 Edge-Case & Failure Mode Matrix
+
+ | Scenario | Risk | Production Mitigation |
+ |:---|:---|:---|
+ | **Empty or Null Inputs** | Unhandled exception or unexpected rendering collapse | Enforce fallback guards, optional chaining, and explicit empty state handlers |
+ | **Network Timeout / Latency** | Hanging operations or duplicate side-effects | Implement bounded abort controllers, exponential backoff, and idempotency keys |
+ | **Concurrency / Race Conditions** | Stale state overwrite or inconsistent data mutations | Use atomic transactions, mutex locking, or cancel-on-resubmit controls |
+ | **Invalid Schema / Malformed Payload** | Downstream runtime errors or security injection | Validate boundary payloads with Zod/Pydantic schemas prior to execution |
+ | **Resource / Memory Saturation** | OOM errors, frame drops, or memory leaks | Clean up listeners, cancel active timers, and enforce pagination/virtualization |
+
+
+ ## 🤖 LLM-Specific Traps Table
+
+ | Anti-Pattern | What AI Commonly Does Wrong | What Is Actually Correct |
+ |:---|:---|:---|
+ | **The Instant Pop Trap** | Conditionally unmounting elements without animated interpolation | Use AnimatePresence or coordinate morphs with continuous geometry |
+ | **Layout Thrashing** | Animating width, height, top, or left inside animation loops | Animate composite-only transform (translate3d, scale) and opacity |
+ | **Sluggish Duration** | Setting micro-interaction transitions to 600ms+ causing interface lag | Cap interactive feedback at 160ms–240ms with snappy ease-out curves |
+
+
+ ## 🏛️ Tribunal Verification & Guardrails
+
+ **Active Reviewers:** `frontend-reviewer` · `motion-reviewer` · `ui-ux-auditor`
+ **Slash Command:** `/review` or `/tribunal-full`
+
+ ### 🔬 Evidence Standard (Tri-State Verification)
+ Every finding, audit statement, or completion claim must classify its factual certainty:
+ - **`[OBSERVED]`**: Directly confirmed in the codebase or verified via executed terminal command.
+ - **`[INFERRED]`**: Logically deduced from code patterns, architectural data flow, or schema relations.
+ - **`[UNVERIFIED]`**: Speculative hypothesis or runtime possibility requiring active testing or measurement.
+
+ ### ✅ Pre-Flight Self-Audit Checklist
+ ```
+ ✅ Does animation maintain 60fps/120fps using transform (translate3d, scale) and opacity?
+ ✅ Is optical mass conserved across state interpolations without volume collapse?
+ ✅ Is duration capped within micro-interaction budgets (150ms–280ms)?
+ ✅ Is prefers-reduced-motion respected with graceful instant fallbacks?
+ ✅ Did I prevent layout thrashing and continuous geometry mutations?
+ ```
+
+ ### 🛑 Verification-Before-Completion (VBC) Protocol
+ **CRITICAL:** You must follow a strict "evidence-based closeout" state machine.
+ - ❌ **Forbidden:** Declaring a task complete because the output "looks correct."
+ - ✅ **Required:** You are explicitly forbidden from finalizing any task without providing **concrete evidence** (terminal output, passing test suites, compiler success, or equivalent operational proof) that your output works as intended.