Mmcp.market

slack-gif-creator skill

by anthropics·anthropics/skills·179k stars

Knowledge and utilities for creating animated GIFs optimized for Slack. Provides constraints, validation tools, and animation concepts. Use when users request animated GIFs for Slack like "make me a GIF of X doing Y for Slack."

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Install the slack-gif-creator skill

A skill is a folder. Copy it into your agent's skills folder and the agent loads it when the task matches its description. 

git clone --depth 1 https://github.com/anthropics/skills.git /tmp/skills
mkdir -p ~/.claude/skills
cp -r /tmp/skills/skills/slack-gif-creator ~/.claude/skills/slack-gif-creator
available in every project

In the Claude apps, zip the folder and upload it from the Skills settings. The folder on GitHub

The instructions your agent would load

SKILL.md as published, without the frontmatter. Read it on GitHub

Slack GIF Creator

A toolkit providing utilities and knowledge for creating animated GIFs optimized for Slack.

Slack Requirements

Dimensions:

  • Emoji GIFs: 128x128 (recommended)
  • Message GIFs: 480x480

Parameters:

  • FPS: 10-30 (lower is smaller file size)
  • Colors: 48-128 (fewer = smaller file size)
  • Duration: Keep under 3 seconds for emoji GIFs

Core Workflow

from core.gif_builder import GIFBuilder
from PIL import Image, ImageDraw

# 1. Create builder
builder = GIFBuilder(width=128, height=128, fps=10)

# 2. Generate frames
for i in range(12):
    frame = Image.new('RGB', (128, 128), (240, 248, 255))
    draw = ImageDraw.Draw(frame)

    # Draw your animation using PIL primitives
    # (circles, polygons, lines, etc.)

    builder.add_frame(frame)

# 3. Save with optimization
builder.save('output.gif', num_colors=48, optimize_for_emoji=True)

Drawing Graphics

Working with User-Uploaded Images

If a user uploads an image, consider whether they want to:

  • Use it directly (e.g., "animate this", "split this into frames")
  • Use it as inspiration (e.g., "make something like this")

Load and work with images using PIL:

from PIL import Image

uploaded = Image.open('file.png')
# Use directly, or just as reference for colors/style

Drawing from Scratch

When drawing graphics from scratch, use PIL ImageDraw primitives:

from PIL import ImageDraw

draw = ImageDraw.Draw(frame)

# Circles/ovals
draw.ellipse([x1, y1, x2, y2], fill=(r, g, b), outline=(r, g, b), width=3)

# Stars, triangles, any polygon
points = [(x1, y1), (x2, y2), (x3, y3), ...]
draw.polygon(points, fill=(r, g, b), outline=(r, g, b), width=3)

# Lines
draw.line([(x1, y1), (x2, y2)], fill=(r, g, b), width=5)

# Rectangles
draw.rectangle([x1, y1, x2, y2], fill=(r, g, b), outline=(r, g, b), width=3)

Don't use: Emoji fonts (unreliable across platforms) or assume pre-packaged graphics exist in this skill.

Making Graphics Look Good

Graphics should look polished and creative, not basic. Here's how:

Use thicker lines - Always set width=2 or higher for outlines and lines. Thin lines (width=1) look choppy and amateurish.

Add visual depth:

  • Use gradients for backgrounds (creategradientbackground)
  • Layer multiple shapes for complexity (e.g., a star with a smaller star inside)

Make shapes more interesting:

  • Don't just draw a plain circle - add highlights, rings, or patterns
  • Stars can have glows (draw larger, semi-transparent versions behind)
  • Combine multiple shapes (stars + sparkles, circles + rings)

Pay attention to colors:

  • Use vibrant, complementary colors
  • Add contrast (dark outlines on light shapes, light outlines on dark shapes)
  • Consider the overall composition

For complex shapes (hearts, snowflakes, etc.):

  • Use combinations of polygons and ellipses
  • Calculate points carefully for symmetry
  • Add details (a heart can have a highlight curve, snowflakes have intricate branches)

Be creative and detailed! A good Slack GIF should look polished, not like placeholder graphics.

Available Utilities

GIFBuilder (core.gif_builder)

Assembles frames and optimizes for Slack:

builder = GIFBuilder(width=128, height=128, fps=10)
builder.add_frame(frame)  # Add PIL Image
builder.add_frames(frames)  # Add list of frames
builder.save('out.gif', num_colors=48, optimize_for_emoji=True, remove_duplicates=True)

Validators (core.validators)

Check if GIF meets Slack requirements:

from core.validators import validate_gif, is_slack_ready

# Detailed validation
passes, info = validate_gif('my.gif', is_emoji=True, verbose=True)

# Quick check
if is_slack_ready('my.gif'):
    print("Ready!")

Easing Functions (core.easing)

Smooth motion instead of linear:

from core.easing import interpolate

# Progress from 0.0 to 1.0
t = i / (num_frames - 1)

# Apply easing
y = interpolate(start=0, end=400, t=t, easing='ease_out')

# Available: linear, ease_in, ease_out, ease_in_out,
#           bounce_out, elastic_out, back_out

Frame Helpers (core.frame_composer)

Convenience functions for common needs:

from core.frame_composer import (
    create_blank_frame,         # Solid color background
    create_gradient_background,  # Vertical gradient
    draw_circle,                # Helper for circles
    draw_text,                  # Simple text rendering
    draw_star                   # 5-pointed star
)

Animation Concepts

Shake/Vibrate

Offset object position with oscillation:

  • Use math.sin() or math.cos() with frame index
  • Add small random variations for natural feel
  • Apply to x and/or y position

Pulse/Heartbeat

Scale object size rhythmically:

  • Use math.sin(t frequency 2 * math.pi) for smooth pulse
  • For heartbeat: two quick pulses then pause (adjust sine wave)
  • Scale between 0.8 and 1.2 of base size

Bounce

Object falls and bounces:

  • Use interpolate() with easing='bounce_out' for landing
  • Use easing='ease_in' for falling (accelerating)
  • Apply gravity by increasing y velocity each frame

Spin/Rotate

Rotate object around center:

  • PIL: image.rotate(angle, resample=Image.BICUBIC)
  • For wobble: use sine wave for angle instead of linear

Fade In/Out

Gradually appear or disappear:

  • Create RGBA image, adjust alpha channel
  • Or use Image.blend(image1, image2, alpha)
  • Fade in: alpha from 0 to 1
  • Fade out: alpha from 1 to 0

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