analyze

name	analyze
description	Analyze a screen recording of an animation to characterize its motion — timing, easing, transforms, and sequencing — so it can be recreated as web code. Use when the user drops or points at a video of an animation (.mp4/.mov/.webm/.mkv/.m4v/.avi/.gif) and says things like "I want this animation on my site", "recreate this motion", "how is this animated", or runs /motiscope:analyze.
argument-hint	[path-to-video] [notes]
allowed-tools	Bash, Read, AskUserQuestion
user-invocable	true

motiscope: analyze

Turn a screen recording of an animation into a precise, target-agnostic animation spec you can hand to /motiscope:recreate. A bundled Python pipeline measures the motion (a dense per-frame motion-energy curve + ffmpeg signal analysis — this is the source of truth for timing and easing) and extracts a small set of curated PNG keyframes for you to see. You combine the two into the spec.

Resolve the scripts directory (do this first)

Every command below runs a bundled script. Set SCRIPTS:

SCRIPTS="${CLAUDE_PLUGIN_ROOT:-}/scripts"
# Fallback for harnesses that don't export CLAUDE_PLUGIN_ROOT: this SKILL.md lives at
# <plugin>/skills/analyze/SKILL.md, so scripts are two levels up. Use the absolute
# path of the directory containing the SKILL.md you just Read.
if [ ! -f "$SCRIPTS/ingest.py" ]; then
  SCRIPTS="<absolute dir of this SKILL.md>/../../scripts"
fi
if [ ! -f "$SCRIPTS/ingest.py" ]; then
  echo "ERROR: cannot find ingest.py — check the plugin install." >&2; exit 1
fi

On Windows use python instead of python3 in every command below.

Step 0 — preflight (silent on success)

python3 "$SCRIPTS/mvsetup.py" --check

Exit 0 → proceed silently. Non-zero → ffmpeg/ffprobe are missing; hand off to /motiscope:doctor (don't try to analyze without them).

Step 1 — resolve the input video

• If the user gave a path (in $1 or their message), use it.
• Otherwise scan the drop folder and project root:

  ls -t animations/*.{mp4,mov,webm,mkv,m4v,avi,gif} *.{mp4,mov,webm,mkv,m4v,avi,gif} 2>/dev/null | head
  

  • Several candidates → ask the user (AskUserQuestion) which one.
  • Exactly one → use it.
  • None → tell the user to drop a recording into animations/ (or pass a path) and stop.

Local files only. motiscope does not download URLs. If the user pastes a URL, ask them to screen-record it and drop the file in.

Step 2 — run the pipeline

python3 "$SCRIPTS/ingest.py" "<video>" --preset balanced

It writes to .motiscope/<slug>/ and prints a summary, the report.md path, and the ordered curated frame list.

Choose a preset (this is the main token dial)

The number of frames you Read is what costs tokens (~300–400 tokens/frame); the numeric analysis is free. Frame count tracks motion complexity, capped by the preset — it does not grow with video length.

Preset	Frame cap	Resolution	Use when
--preset draft	12	512px	quick look, tight token budget
--preset balanced (default)	32 (usually lands 8–20 after dedup)	640px	most cases
--preset detailed	48	960px	dense multi-beat sequences, or reading on-screen text
--preset landing	44	1280px	web/landing walkthroughs — cover each section's design at readable resolution + its in-section motion

Start with balanced. Only reach for detailed if the animation is intricate or you couldn't read a label; use draft for a fast first pass. If the user hasn't said, pick balanced and mention they can ask for more detail.

Focus a section of a longer video (--start / --end)

For anything longer than ~15s, or when the user points at a specific moment ("the part around 0:12", "the last second"), analyze just that window instead of a sparse whole-clip scan. Times accept SS, MM:SS, or HH:MM:SS; frame/segment timestamps come back in absolute source time.

python3 "$SCRIPTS/ingest.py" "<video>" --preset detailed --start 0:12 --end 0:15

Capture fast content densely (--fps)

Within a (short) focus window you can force a uniform sample rate so nothing between keyposes is missed — e.g. --fps 20 gives up to a frame every ~50ms. Near-identical frames are still collapsed unless you pass --no-dedup. Combine with a short window so the budget isn't blown:

python3 "$SCRIPTS/ingest.py" "<video>" --start 1.0 --end 3.0 --fps 20 --frame-budget 48

Complex / long animations: auto-decompose

For clips ≥8s with two or more motion beats, ingest.py auto-decomposes by default: it finds the beats, then concentrates frames on each motion segment (drilling densely) and gives each hold just one representative frame — so the budget is spent on motion, not dead air. A 10s clip with a 5s hold in the middle spends ~0 frames on the hold. The report notes when this happened.

Control it with --decompose (force on) / --no-decompose (force the flat single-pass). Auto is the right default; force it off only if you specifically want even coverage across the whole timeline.

Other flags: --frame-budget N / --resolution W override the preset; --format jpg for gradient-heavy recordings that bloat as PNG; --no-dedup to keep every sampled frame; --out DIR (default .motiscope/).

Small elements register now. The primary motion signal is localized (built from the most-active regions of the frame), so a small button/card/icon moving on a large page reads as real motion instead of washing out. The stagger direction in the report tells you the sequencing (e.g. left-to-right, ~200ms each) — use it when building the spec's stagger.

Step 3 — read the analysis, then the frames

The division of labor is the whole point:

• The numbers give you the WHEN. report.md measured the timing you can't see in a still: exact durations, the per-segment easing curve (a real cubic-bezier fitted from the velocity profile), the beat/segment boundaries, the stagger timing (~ms between items), and any loop period. Trust these — a screenshot has no time axis, so this is the one thing that isn't guessable.
• You give the WHAT. The frames are yours to read with full vision. Identify the elements and — crucially — what kind of animation each one is. motiscope does not classify animation types, and you are not limited to fade/slide/scale: name whatever you actually see — a mask reveal, a path/line draw, a morph, a rotate/skew, a 3D flip, a text split/typewriter, a blur, a color shift, a parallax, a physics/spring bounce, particles, a clip-path wipe, anything. The pipeline deliberately leaves this to your perception because you're better at it than any hand-coded classifier.

Steps:

1. Read the printed report.md for the measured timing (energy sparkline, segment/beat table with the fitted cubic-bezier, stagger timing, loop).
2. Read every curated frame in one message (parallel Reads) so you see them in order. Filenames encode t=<seconds> + why each was picked, so you can line frames up against the measured timeline.

Read timing from the numbers; read everything else from the frames.

The frames are evidence, not an inventory

Frames are chosen by the motion-energy signal. Anything small, low-contrast, briefly visible, or mostly occluded barely moves that signal and may not appear in a single curated frame — while still being a headline feature of the animation. A train crossing a bridge was missed exactly this way.

Before you commit to a spec:

• Ask "is anything else moving?" and go check the clip, not just the frames. Diff a region across the whole video, or sample uniformly at a rate the curation skipped.
• If the user names something you cannot see, believe them and go look. Its absence from the frames is not evidence of its absence from the animation.

Before you trust a number

A failed automated measurement does not crash. It returns a confident float.

• Two estimators, or you have none. Measure the same quantity a second, independent way (different scale, different feature, different algorithm). Agreement is a result; a disagreement of 6× means at least one is lying, and you cannot tell which by looking.
• Say "not recoverable" when methods disagree. Averaging -0.03 .. 0.63 into 0.30 invents a fact. Reporting the range is the finding.
• Occluded features report clamped constants. A value that is pinned at a frame edge, or that stays put while everything around it moves, is not a measurement.
• Scroll-driven ≠ time-driven. For a parallax, scroll-zoom or pinned section, the seconds in the recording are the recorder's. Only ratios (layer speed ÷ scroll speed) are intrinsic. One clip can contain both kinds of clock.

The full list, with the real failures behind each one, is in references/measurement-traps.md. Read it before reporting any velocity, easing or ratio you derived yourself rather than reading out of report.md.

Step 4 — produce the animation spec

Emit a target-agnostic spec: a timing skeleton (measured) + your visual reading (what each element is and does). Schema:

{
  "duration_ms": 2000,
  "canvas": { "w": 800, "h": 600, "bg": "#ffffff" },
  "loop": false,
  "scroll_driven": false,
  "elements": [{ "id": "card", "role": "card" }],
  "timeline": [
    { "target": "card", "start_ms": 0, "dur_ms": 400,
      "ease": "ease-out", "bezier": [0.16, 1, 0.3, 1],
      "animation": "fade + slide up",
      "props": { "opacity": [0, 1], "y": [24, 0] },
      "source": { "timing": "measured", "everything_else": "seen" } }
  ],
  "stagger": { "children": "card", "each_ms": 80 },
  "notes": "e.g. 'headline does a per-word mask reveal'; 'logo path draws in'"
}

Rules:

• start_ms, dur_ms, ease, bezier, stagger each_ms, loop period_ms are MEASURED — copy them from report.md/motion.json verbatim. Especially: use the fitted cubic-bezier directly (CSS cubic-bezier(...), Framer [..], GSAP CustomEase) — it's the real curve, not a guess.
• animation, elements, props (magnitudes/direction/colors), and the animation type are YOURS from the frames — describe the actual effect in the free-text animation field (open vocabulary), and put your best-estimate property values in props. Direction, scale, rotation, opacity, morph, draw, etc. all come from what you see, not from the numbers.
• Be honest about a leading hold: a gentle ease-in's slow start can read as a short hold (sub-pixel motion is invisible in the analysis thumbnails). Check the first frames — if the element already moved slightly, treat it as the start of the ease, not a delay.
• Loops: if the report flags a loop, set "loop": true with period_ms. It can be a half-cycle for back-and-forth motion — decide loop-vs-yoyo from the frames.
• If an effect can't be reduced to props (a complex morph, a particle system, a shader), say so in animation/notes and let recreate build it directly from your description — don't force it into simple props.
• Scroll-driven captures: set "scroll_driven": true and do not copy duration_ms into the spec as if it were the design's. Report ratios (layer speed ÷ page-scroll speed) and note which quantities belong to the recorder. A clip can be scroll-driven and contain a time-driven object (a train, a spinner, a looping badge) — measure that object's speed separately.
• Label every number you derived yourself (a velocity, a ratio, a period) as measured, estimated, or not recoverable. Never let a chosen value read as a measured one.

Step 5 — offer to recreate

Summarize the animation in one or two sentences, then offer:

Recreate this as GSAP, CSS, Framer Motion, or Lottie/SVG? Run /motiscope:recreate <target>.

The spec you just built is saved in .motiscope/<slug>/manifest.json; recreate will reload it (plus motion.json) if you don't hand it over directly.

Notes

• Token cost lives entirely in the frames (~24–48 PNGs). The motion curve is numbers — effectively free. If you already analyzed this clip in the session, don't re-run; reason from what you have.
• Best results come from high-fps, lightly-compressed captures. Warn the user if a recording is heavily compressed or very low frame rate.