Beat Sync Reel

What it does

When your agent uses it

• Tasks that involve Video production
• Tasks that involve AI video generation

Example prompts

• “Use the beat-sync-reel skill to generate Instagram Reels where product image cuts are synced to audio beats”
• “/beat-sync-reel”

Requirements

• Python 3
• Pre-approved tools (allowed-tools): Bash, Read, Write, Edit, Grep, Glob, WebSearch

Workflow steps

7 steps, taken from the step headings in SKILL.md.

1. 1Resolve Audio
2. 2Detect Beats
3. 3Classify & Filter Images
4. 4Create Ken Burns Scenes
5. 5Create End Card (Optional)
6. 6Concatenate Scenes
7. 7Add Audio

What it can do on your machine

Read from SKILL.md and the folder at commit c650c6d. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Bash
  • Read
  • Write
  • Edit
  • Grep
  • Glob
  • WebSearch

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • ffmpeg
  • yt-dlp
  • ffprobe

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Hosts in commands or code, which the agent is likely to contact:

  • damensch.com
  • instagram.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Beat Sync Reel loads about 2.5k tokens when it runs. Until then it costs about 76 tokens; SKILL.md has 833 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~76

When it runs · the whole SKILL.md, loaded when a task matches

~2.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NotePre-approves every shell command (allowed-tools: Bash)SKILL.md

  allowed-tools: Bash, Read, Write, Edit, Grep, Glob, WebSearch

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from gooseworks-ai/goose-skills at commit c650c6d, republished under its MIT licence (© gooseworks-ai). 833 words, ~2,489 tokens.

name

beat-sync-reel

description

Generates Instagram Reels where product image cuts are synced to audio beats. Accepts audio as a local file, URL, or search query. Uses librosa for beat detection, FFmpeg Ken Burns for scene animation, and Pillow for text overlays. No AI video generation — fully free, fast, and scalable.

allowed-tools

Bash, Read, Write, Edit, Grep, Glob, WebSearch

user-invocable

true

argument-hint

[product-url-or-image-paths] [audio-source]

# Just verify it exists and get duration
ffprobe -v quiet -print_format json -show_format "audio.mp3"

yt-dlp -x --audio-format mp3 -o "<workdir>/audio.%(ext)s" "<URL>"

import librosa
import numpy as np

y, sr = librosa.load("audio.mp3", sr=None)
tempo, beat_frames = librosa.beat.beat_track(y=y, sr=sr)
beat_times = librosa.frames_to_time(beat_frames, sr=sr)
beat_times = [float(t) for t in beat_times]

# beat_freq = 2 means every 2nd beat
cut_times = [0.0] + [beat_times[i] for i in range(beat_freq - 1, len(beat_times), beat_freq)]

start, end = 0.0, 15.0  # or user-provided
cut_times = [t - start for t in cut_times if start <= t < end]
if cut_times[0] != 0.0:
    cut_times.insert(0, 0.0)

# Zoom in center
ffmpeg -y -loop 1 -i "image.jpg" \
  -vf "scale=2160:3840,zoompan=z='1+0.08*in/{frames}':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':d={frames}:s=1080x1920:fps=25" \
  -t {duration} -c:v libx264 -pix_fmt yuv420p -r 25 scene.mp4

# Zoom out center
zoompan=z='1.15-0.08*in/{frames}':x='iw/2-(iw/zoom/2)':y='ih/2-(ih/zoom/2)':d={frames}:s=1080x1920:fps=25

# Pan left to right
zoompan=z='1.08':x='(iw-iw/zoom)*in/{frames}':y='ih/2-(ih/zoom/2)':d={frames}:s=1080x1920:fps=25

# Pan right to left
zoompan=z='1.08':x='(iw-iw/zoom)*(1-in/{frames})':y='ih/2-(ih/zoom/2)':d={frames}:s=1080x1920:fps=25

# Zoom in top-center (for torso/face crops)
zoompan=z='1+0.08*in/{frames}':x='iw/2-(iw/zoom/2)':y='ih/4-(ih/zoom/4)':d={frames}:s=1080x1920:fps=25

# Pan up
zoompan=z='1.06':x='iw/2-(iw/zoom/2)':y='(ih-ih/zoom)*(1-in/{frames})':d={frames}:s=1080x1920:fps=25

from PIL import Image, ImageDraw, ImageFont

card = Image.new("RGBA", (1080, 1920), (20, 20, 20, 255))
draw = ImageDraw.Draw(card)
# Brand name (centered, y=750)
# Product name (centered, y=830)
# Price (centered, y=920, accent color)
# CTA (centered, y=1020, muted)
card.save("endcard.png")

ffmpeg -y -loop 1 -i endcard.png -vf "scale=1080:1920" \
  -t 2 -c:v libx264 -pix_fmt yuv420p -r 25 endcard.mp4

cat > concat.txt << EOF
file 'scene-00.mp4'
file 'scene-01.mp4'
...
file 'endcard.mp4'
EOF

ffmpeg -y -f concat -safe 0 -i concat.txt \
  -c:v libx264 -pix_fmt yuv420p -r 25 reel-silent.mp4

ffmpeg -y -i reel-silent.mp4 -i audio.mp3 \
  -filter_complex "[1:a]atrim={start}:{end},asetpts=PTS-STARTPTS,afade=t=in:st=0:d=0.5,afade=t=out:st={fade_start}:d=2,volume=0.8[aud]" \
  -map 0:v -map "[aud]" \
  -c:v copy -c:a aac -shortest output.mp4

User: "Make a beat-sync reel for this product: https://www.damensch.com/products/full-sleeve-polo
       Use this audio: https://www.instagram.com/reels/audio/123456789/
       Cut on every 2nd beat, use the first 15 seconds"

Agent:
1. Downloads audio with yt-dlp
2. Scrapes product images from URL
3. Detects beats with librosa
4. Creates Ken Burns clips at beat intervals
5. Adds end card with product info
6. Mixes audio
7. Outputs reel

© gooseworks-ai, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file in skills/design/packs/video-production/beat-sync-reel of gooseworks-ai/goose-skills.

• SKILL.md
• skill.meta.json

Open the folder on GitHubat commit c650c6d

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in gooseworks-ai/goose-skills, which our catalogue first saw on October 7, 2026.

• criptogus/agent-evolve-network.claude/skills/beat-sync-reel