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animate-to-audio

Animate a layer property from audio amplitude or beat transients in a single call, bypassing separate waveform analysis and manual keyframe creation.

Instructions

Generate After Effects keyframes for a layer property directly from an audio file's waveform, in one call - no need to call analyze-audio-waveform and compute keyframes by hand first. Two modes: 'waveform' follows the amplitude envelope continuously (a VU-meter style effect - glow intensity, scale, or opacity riding the music), one keyframe per analyzed sample. 'peaks' pulses the property at each detected transient/beat and decays back to baseline (a beat-pop style effect - e.g. a logo scaling up on every kick). Accepts any audio format ffmpeg supports (mp3, m4a/aac, ogg, flac, ...) the same way analyze-audio-waveform does; uncompressed WAV needs no extra dependency. Targets a plain layer property (e.g. 'ADBE Opacity') by default, or an effect's property when effectIndex/effectName/effectMatchName is given.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
modeNo'waveform' (default): continuous amplitude-follow. 'peaks': discrete pulse-and-decay at each detected transient.
curveNoResponse shaping (default: linear). 'exponential' emphasizes loud peaks (punchier); 'logarithmic' boosts quiet-passage detail. In 'peaks' mode this only affects velocitySensitivePeaks scaling.
compNameNoName of the target composition. Preferred over compIndex when both are given.
filePathYesAbsolute path to the audio file (obtained from get-audio-info sourceFilePath).
compIndexNo1-based composition index, used if compName is not given.
layerNameNoName of the target layer (alternative to layerIndex).
numPointsNoWaveform samples to analyze, each becoming one keyframe in 'waveform' mode (default: 100). Ignored for keyframe generation in 'peaks' mode (still used to detect the peaks themselves), where the number of keyframes instead follows how many transients are detected. Kept well below analyze-audio-waveform's own cap since every point here becomes a real After Effects keyframe.
outputMaxYesProperty value at full amplitude (waveform amplitude 1, or peaks-mode value at the instant of a hit).
outputMinYesProperty value at silence/rest (waveform amplitude 0, or peaks-mode baseline between hits).
startTimeNoSeconds to offset every generated keyframe by, to start the animation partway through the comp (default: 0).
effectNameNoDisplay name of the effect to target.
layerIndexNo1-based index of the target layer within the composition.
effectIndexNo1-based index of the effect in the layer's Effects group, to target an effect property instead of a plain layer property.
propertyNameNoTarget property name or matchName (e.g. 'ADBE Opacity', 'ADBE Scale', 'ADBE Rotate Z' - matchNames are locale-independent and preferred). Used when propertyPath is not given, or as the effect-property fallback.
propertyPathNoPath to the target property, from the effect root (if an effect selector is given) or from the layer root otherwise, e.g. ['Compositing Options', 'Effect Opacity'] or [3, 1].
clearExistingNoRemove the property's existing keyframes first (default: true).
propertyIndexNoFallback target property index under the effect root (effect targeting only).
effectMatchNameNoInternal matchName of the effect to target.
keyframeOptionsNoOptional graph/easing controls applied uniformly to every keyframe this call generates.
smoothingWindowNoWaveform mode only: moving-average window (in samples) to smooth out jittery amplitude before keyframing (default: 3, use 1 to disable).
peakDecaySecondsNoPeaks mode only: seconds to fall back to outputMin after each hit (default: 0.15).
velocitySensitivePeaksNoPeaks mode only: scale each hit's height by how loud that specific transient was, instead of every hit jumping to the same outputMax (default: true).
Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Despite no annotations, the description discloses key behavioral traits: it modifies layer properties (creates keyframes), clears existing ones by default, handles multiple audio formats, and explains mode-specific behaviors (e.g., peaks mode keyframe count depends on transients). It lacks explicit mention of whether the operation is reversible or if it has side effects beyond keyframe creation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single dense paragraph that covers all essential information without unnecessary repetition. However, a more structured format (e.g., bullet points for modes) could improve readability for agents, especially given the parameter complexity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has 22 parameters, two modes, and nested objects, but no output schema. The description explains parameter usage and mode differences thoroughly but omits what the tool returns (e.g., success/failure, keyframe count). This gap may leave agents uncertain about how to verify the tool's effect.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 100% schema coverage, the description still adds substantial value by explaining parameter interactions (e.g., numPoints for waveform vs peaks, smoothingWindow only for waveform), providing examples ('ADBE Opacity'), and clarifying ambiguous fields like propertyPath and effect selectors. This goes well beyond the schema's concise descriptions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: generating After Effects keyframes from an audio waveform in one call, directly contrasting with the sibling tool 'analyze-audio-waveform'. It uses specific verbs ('Generate... keyframes') and resource ('layer property from audio file'), making it unmistakable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explicitly compares two modes ('waveform' and 'peaks') with real-world examples (VU-meter, beat-pop), and explains when to use this tool over the sibling 'analyze-audio-waveform'. However, it does not explicitly state when not to use it or list alternative tools for other scenarios, slightly reducing clarity.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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