Build Gesture Animation

Build Gesture Animation

Build and verify a gesture-controlled animation website through a closed-loop workflow: establish a valid input, transform it, measure the output, and fix or rerun the failing stage until every delivery check passes.

Step 0: Create Tasks And Memory

Before running commands, create one task for each active workflow stage and keep only one implementation task in progress at a time. Use the client's native task and memory tools when available. Always maintain portable project records too:

• .agents/tasks/build-gesture-animation.md for task status and gate evidence;
• .agents/memory/build-gesture-animation.md for durable facts, decisions,

validation results, warnings, and unresolved issues.

Update both records after every completed or failed gate, not only at final delivery. Never store credentials, camera images, user biometrics, large command logs, or generated media in memory. Read [task-memory.md](references/task-memory.md) for the required format.

If no project directory exists yet, begin with the client-native task list and create the portable files immediately after the output path is chosen.

Step 1: Check The Environment

Run:

python3 scripts/check_environment.py

Require Python 3.9+, FFmpeg, ffprobe, and FFmpeg WebP encoding. Do not install missing system dependencies without the user's permission. Give the platform- appropriate command printed by the script and wait when FFmpeg is unavailable.

Step 2: Establish The Source

Ask whether the user already has a video or needs to generate one.

• For an existing video, confirm its path and inspect it before changing files.

Use ffprobe or prepare_media.py --inspect-only to report duration, dimensions, rotation, and decoded frame count.

• For a video that does not exist yet, determine whether the current agent can

generate video. If not, state that limitation plainly and prepare an English prompt, negative prompt, and explanation in the user's language. Read [video-prompting.md](references/video-prompting.md). Wait for the finished video before continuing.

Do not silently replace, delete, or modify the source video.

Step 3: Define The Project

Collect only decisions that cannot be inferred safely:

1. Site title and subtitle.
2. Artwork ID and label for each source video.
3. Frame count, defaulting to 60 and constrained to 24-120.
4. Any combination of Palm, Pinch, Span, and Mouth controls.
5. invert for controls whose direction should be reversed.

Use Swipe only for cyclic artwork navigation. Do not add it as a primary control tab. Read [gesture-controls.md](references/gesture-controls.md) for the control semantics and calibration invariant.

Step 4: Prepare Media

Create the destination project before extracting frames, then process each source into frames/:

python3 scripts/prepare_media.py \
  --input /absolute/path/source.mp4 \
  --output /absolute/path/project/frames/artwork-id \
  --frames 60

The script selects decoded source frame numbers uniformly, always includes the first and last frame, center-crops to exact 4:3, limits output to 1280x960 without upscaling, and writes directly to numbered WebP files. If the source contains fewer frames than requested, accept the smaller real frame count and use it in project configuration. Never manufacture duplicate frames.

Read [media-pipeline.md](references/media-pipeline.md) before changing encoding defaults or handling rotation and low-resolution inputs.

Step 5: Scaffold The Site

Write one project.config.json with the exact output frame counts, then run:

python3 scripts/scaffold_site.py \
  --output /absolute/path/project \
  --config /absolute/path/project.config.json \
  --preserve-frames

The generated site is static HTML, CSS, and JavaScript. It reads title, subtitle, artworks, tabs, instructions, inversion, and navigation from the configuration. Keep MediaPipe thresholds and runtime performance settings in the template rather than exposing them to ordinary users.

Step 6: Validate And Close The Loop

Run validation after every media or configuration change:

python3 scripts/validate_project.py /absolute/path/project

Treat validation as a gate. Fix the reported stage and rerun until all checks pass. Validation must confirm:

• valid configuration and allowed control types;
• safe, unique artwork IDs and usable frame paths;
• exact continuous numbering from 1.webp;
• configuration counts matching actual files;
• decodable WebP frames with exact 4:3 dimensions;
• required template files and CDN model references.

Do not claim completion while validation fails.

Step 7: Serve And Verify Visually

Start a localhost server so camera permission runs in a secure browser context:

python3 scripts/serve_site.py /absolute/path/project

Open the printed URL and verify desktop and mobile layouts. Confirm the main visual remains 4:3, the desktop camera stays in the control column, the mobile camera is draggable and above all content, tracking loss holds the last frame, and artwork navigation loops when enabled.

Report the local URL, project directory, frame counts, total media size, and any validation warnings. Finish by reconciling the native task list with the portable task record and writing the final validation snapshot to memory.

Installation

Use scripts/install_skill.py for Codex, Claude Code, Cursor, GitHub Copilot, or a project-local .agents/skills installation. Read [client-installation.md](references/client-installation.md) before installing or replacing an existing copy.

Boundaries

• Generate prompts, not video, when no video-generation capability is present.
• Do not deploy to Vercel or any external host.
• Do not add custom landmark formulas or pose models in this version.
• Do not embed user media, credentials, or absolute local paths in this Skill.
• Stop for user input when the source is missing, a destructive replacement is

required, or validation exposes an ambiguous media problem.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: senlindesign
• Source: senlindesign/build-gesture-animation
• License: MIT

Install and usage instructions live in the source repository linked above.