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HyperFrames Keyframes

Free

Create seek-safe keyframes for advanced animations.

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Free · Opens the source repo

What HyperFrames Keyframes does

HyperFrames Keyframes is a specialized tool designed for developers and designers who need to create precise and reliable keyframe animations in 2D and 3D environments. It supports various animation frameworks such as GSAP, CSS keyframes, Anime.js, and more, ensuring that animations are not only visually appealing but also maintain continuity and performance. The skill emphasizes the importance of seek-safe keyframes, which allow for smooth playback and reliable state transitions during animations.

The procedure for using HyperFrames Keyframes involves identifying the animated subject and its visible states, selecting the appropriate mechanism for the animation, and authoring keyframes in the specified runtime. The skill provides a structured approach to building animations, ensuring that each keyframe is verified through diagnostics before final rendering. By adhering to the outlined rules and guidelines, users can create animations that are both effective and maintainable.

This skill is particularly useful for developers working on interactive web applications or designers focused on creating dynamic visual content. It streamlines the animation creation process by providing clear instructions and best practices, making it easier to implement complex animations without sacrificing performance or quality. HyperFrames Keyframes is ideal for projects where precise control over animation timing and behavior is critical.

However, it is important to note that HyperFrames Keyframes is not intended for broader scene strategies or general video planning. Users looking to develop comprehensive media projects or those requiring extensive design elements may find this skill too narrow in focus. Instead, it excels in scenarios where detailed, seek-safe animations are paramount, making it a valuable tool for specialized animation tasks.

When to use it

Use HyperFrames Keyframes when you need to implement precise animations in web applications or interactive designs.

When not to use it

Avoid this skill for general video planning or broad scene design, as it focuses specifically on keyframe animation.

What you can build with it

Interactive Web Applications

Implement precise animations for user interactions, enhancing the overall user experience.

Dynamic Visual Content

Create engaging animations for presentations or marketing materials that require detailed visual effects.

Game Development

Utilize seek-safe keyframes to ensure smooth character movements and transitions in web-based games.

How to install HyperFrames Keyframes

View source

1. Install with the skills CLI

npx skills add heygen-com/hyperframes/hyperframes-keyframes --agent claude-code

2. Or install it manually

Download the skill folder and drop it into ~/.claude/skills/ for all projects, or .claude/skills/ to scope it to one repo. Restart Claude Code so it picks up the new skill.

Anthropic's agentic coding CLI, and the reference implementation of Agent Skills. Drop a skill folder into ~/.claude/skills and Claude Code loads it automatically whenever a task matches the skill's description. Claude Code docs

Inside SKILL.md

Written by heygen-com

HyperFrames Keyframes

Keyframes are a pose contract: visible states, continuous subject identity, seek-safe runtime, verified pixels.

Use hyperframes-animation for broad scene recipes. Use hyperframes-cli for full command docs. Use references/keyframe-patterns.md only when choosing implementation mechanisms, not visual style.

Procedure

  1. Identify the animated subject, visible states, final state, and runtime.
  2. Choose the smallest mechanism that proves the prompt. Read references/keyframe-patterns.md only if the mechanism is unclear.
  3. Author seek-safe keyframes in the declared runtime. Build synchronously and register the runtime instance.
  4. Verify with hyperframes lint, hyperframes check, hyperframes keyframes, one focused --shot, and snapshots at proof times.
  5. If proof fails, fix the source keyframes and rerun the smallest failing diagnostic before rendering.

Contract

  • Name the moving subject.
  • Name the poses needed to prove the intended motion, including the final state.
  • Keyframe visible channels, not hidden helper state.
  • Preserve object identity when continuity matters.
  • Crossfade only when the intended motion is replacement or dissolve.
  • Hold readable or semantic states long enough to see.
  • Final frame is part of the animation, not cleanup.
  • Do not reset to rest unless requested.
  • Do not end on black unless requested.
  • If editing a starter scene, preserve layout, copy, assets, colors, and final state unless asked to redesign.

Runtime Rules

GSAP:

  • build synchronously at page load
  • use gsap.timeline({ paused: true })
  • register as window.__timelines[compositionId]
  • registry key must match data-composition-id
  • do not call tl.play() for render-critical motion
  • keep repeats finite

CSS keyframes:

  • finite duration and iteration count
  • deterministic delay
  • animation-fill-mode: both
  • use data-start when timing belongs to a clip

Anime.js:

  • create synchronously
  • autoplay: false
  • finite duration and loops
  • push every instance to window.__hfAnime

WAAPI:

  • finite duration
  • fill: "both"
  • deterministic construction
  • the text surface does not list WAAPI; verify with --shot (it seeks WAAPI) and snapshots

Never use for render-critical motion:

  • Date.now()
  • performance.now()
  • unseeded Math.random()
  • hover/scroll triggers
  • timers
  • async-created timelines
  • unregistered requestAnimationFrame
  • infinite loops

GSAP Skeleton

const root = document.querySelector("[data-composition-id]");
const compositionId = root.dataset.compositionId;
const tl = gsap.timeline({ paused: true });

tl.addLabel("state-a", 0);
tl.to(".subject", {
  keyframes: [
    { x: 0, opacity: 1, duration: 0.2 },
    { x: 120, opacity: 1, duration: 0.4, ease: "power2.out" },
    { x: 100, opacity: 1, duration: 0.2, ease: "power2.inOut" },
  ],
  ease: "none",
});

window.__timelines = window.__timelines || {};
window.__timelines[compositionId] = tl;

Use labels for semantic states. Use position parameters instead of chained delays. Use immediateRender: false for later from()/fromTo() tweens touching the same property.

Keyframe Forms

  • Array keyframes: pose ladder with per-step duration/ease.
  • Percentage keyframes: exact timing inside one tween.
  • Property arrays: compact multi-stop changes.
  • ease: "none" on the parent when each stop carries its own easing.
  • easeEach when every segment should share the same feel.

Do not copy numeric distances or timing from examples. Derive them from the actual composition geometry and duration.

For one subject moving between two boxes, prefer one continuous transform tween or FLIP. Split x/y/scale into multiple eased keyframes only when the viewer should feel distinct beats; every segment changes velocity and can read as a hitch.

Channels

Prefer compositor/visual channels: x/y/z, xPercent/yPercent, scale, rotationX/Y/Z, skew, transformOrigin, svgOrigin, opacity, autoAlpha, clip-path, masks, CSS vars, SVG path/dash values, camera transforms, shader uniforms.

Avoid layout/lifecycle channels: top/left/right/bottom, width/height, margin/padding, display, visibility, late DOM creation, helper overlays doing subject motion.

For visibility changes, use autoAlpha on the registered seekable GSAP timeline, or a zero-duration tl.set() at an explicit boundary. Target only a non-clip element or a wrapper inside the clip; never target .clip itself. Never duration-tween raw visibility, and never tween display.

Mechanism Choice

Choose the smallest mechanism that proves the prompt:

NeedMechanism
Same subject changes box or hierarchyshared element / FLIP
Subject travels a visible routepath travel
Stroke grows or tracesstroke draw
Shape becomes another shapeshape interpolation
Reveal boundary is visibleclip, mask, or shader uniform
Many items move with orderstagger / indexed delay
Text itself movesline, word, character, or band subdivision
Surface bends, stretches, or cropsparent/child counter-transform
UI has statesexplicit state machine
Scene has depthDOM 3D, Three.js, or WebGL camera/object keyframes

Mechanisms can combine, but each one must clarify the idea. Decoration is not proof.

Timing

  • Anticipation only when it clarifies cause or direction.
  • Acceleration leaves rest.
  • Peak proof shows the mechanism unmistakably.
  • Follow-through sells energy and direction.
  • Overshoot only when the subject should feel elastic or tactile.
  • Constant-speed path travel usually needs ease: "none".
  • Discrete UI states usually need a sharp ease-out.
  • Repeated elements need ordered offsets, not identical timing.
  • Final lockups need longer holds than transition poses.
  • Smoothness means continuous velocity on the same subject.
  • Do not overlap tweens that write the same transform property unless the overlap is intentional and verified.
  • Avoid animating large clip-path/mask changes while the same hero surface is also scaling or traveling; use nested reveals after the main move settles.

Text

Preserve line boxes, word spacing, readability, and final fit. If text moves internally, move the glyphs or masked bands, not only decorations around the text. Snapshot readable frames.

SVG

For stroke growth prefer DrawSVGPlugin, then stroke-dasharray/stroke-dashoffset. For shape interpolation prefer MorphSVGPlugin; convert primitives to paths when needed and split complex silhouettes into simpler parts.

3D

Scale alone is fake depth. Use perspective on a stable parent, transform-style: preserve-3d, z travel, rotation, camera/world motion, occlusion, and layer order when objects cross.

Use one or two diagnostic angles that expose the depth relationship. If angled proof shows no depth crossing, improve z/camera/occlusion.

Canvas / WebGL

Keyframe camera position, camera target, object transform, material opacity, shader uniforms, and postprocess intensity through deterministic state. Render from HyperFrames time. Use --ghost because marker boxes cannot see internal canvas motion.

CLI Proof

npx hyperframes lint
npx hyperframes check
npx hyperframes keyframes .
npx hyperframes keyframes . --json
npx hyperframes keyframes . --runtime all
npx hyperframes keyframes . --selector "<selector>" --shot "<file>" --samples <n>
npx hyperframes keyframes . --selector "<selector>" --shot "<file>" --layout strip --from <t0> --to <t1>
npx hyperframes keyframes . --shot "<file>" --ghost --angle <angle>
npx hyperframes snapshot . --at <times>

Choose <selector> for the real animated subject. Choose <times> for first frame, proof poses, final-minus-hold, and exact final. Choose <angle> only when depth must be proven.

ToolProves
keyframestargets, explicit stops, paths, traces, composed parent/child motion, CSS stops, Anime registration
--shotghosts, route shape, time spacing, DOM 3D projection, focused selector proof
--layout stripin-place motion, overlaps, contact, subtle scale/opacity, text waves
--ghostcanvas, WebGL, shader motion, rendered 3D
snapshot --atmasks, text readability, full state, final lockup, black/reset tails

If selector proof looks wrong:

  1. rerun --json
  2. find the actual animated target
  3. shoot that target
  4. snapshot full frames
  5. trust painted pixels over logs

Diagnostic Reading

flat means no explicit middle poses. keyframes means explicit stops exist. motionPath means a route exists. trace means multi-stroke drawing. composed with means child motion inherits parent motion.

Even ghost spacing means constant speed. Clustered ghosts mean slow-in or settle. Large gaps mean fast travel.

A helper-selector shot is not proof. An onion shot over a broken full frame is not proof.

Error Handling

FailureFix
endpoint-onlyadd middle poses, hold peak proof, rerun --shot
identity breakkeep one element alive, use shared source/final boxes, remove substitute crossfade
fake 3Dadd z/camera travel, occlusion, angled proof
wrong finaladd final hold, snapshot final-minus-hold and exact final
unseekable runtimepause autoplay, register instance, remove timers, build synchronously
unreadable textpreserve line boxes, reduce displacement, add final hold, snapshot text frames

Done

Run hyperframes lint, hyperframes check, hyperframes keyframes, one focused --shot, and snapshots. Confirm first frame, proof poses, final-minus-hold, exact final, subject-owned motion, and no debug overlays.

Frequently asked questions about HyperFrames Keyframes

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