arc-explainer: Skill for Claude Code

Slack GIF Creator - Flexible Toolkit

A toolkit for creating animated GIFs optimized for Slack. Provides validators for Slack's constraints, composable animation primitives, and optional helper utilities. Apply these tools however needed to achieve the creative vision.

Slack's Requirements

Slack has specific requirements for GIFs based on their use:

Message GIFs:

• Max size: ~2MB
• Optimal dimensions: 480x480
• Typical FPS: 15-20
• Color limit: 128-256
• Duration: 2-5s

Emoji GIFs:

• Max size: 64KB (strict limit)
• Optimal dimensions: 128x128
• Typical FPS: 10-12
• Color limit: 32-48
• Duration: 1-2s

Emoji GIFs are challenging - the 64KB limit is strict. Strategies that help:

• Limit to 10-15 frames total
• Use 32-48 colors maximum
• Keep designs simple
• Avoid gradients
• Validate file size frequently

Toolkit Structure

This skill provides three types of tools:

1. Validators - Check if a GIF meets Slack's requirements
2. Animation Primitives - Composable building blocks for motion (shake, bounce, move, kaleidoscope)
3. Helper Utilities - Optional functions for common needs (text, colors, effects)

Complete creative freedom is available in how these tools are applied.

Core Validators

To ensure a GIF meets Slack's constraints, use these validators:

from core.gif_builder import GIFBuilder

# After creating your GIF, check if it meets requirements
builder = GIFBuilder(width=128, height=128, fps=10)
# ... add your frames however you want ...

# Save and check size
info = builder.save('emoji.gif', num_colors=48, optimize_for_emoji=True)

# The save method automatically warns if file exceeds limits
# info dict contains: size_kb, size_mb, frame_count, duration_seconds

File size validator:

from core.validators import check_slack_size

# Check if GIF meets size limits
passes, info = check_slack_size('emoji.gif', is_emoji=True)
# Returns: (True/False, dict with size details)

Dimension validator:

from core.validators import validate_dimensions

# Check dimensions
passes, info = validate_dimensions(128, 128, is_emoji=True)
# Returns: (True/False, dict with dimension details)