Slack GIF Creator

Slack GIF Creator is Anthropic's official Claude Agent Skill for producing animated GIFs optimized for Slack. It bundles the knowledge of Slack's exact constraints, a set of Python utilities built on PIL/Pillow, and a library of animation concepts so Claude can generate a polished GIF the moment you ask for one — for example, "make me a GIF of X doing Y for Slack."

What is Slack GIF Creator?

Slack GIF Creator is a toolkit that combines Slack's GIF requirements with reusable code utilities. It knows the target dimensions (128x128 for custom emoji, 480x480 for message GIFs), the workable parameter ranges (FPS 10-30, 48-128 colors, under 3 seconds for emoji), and how to validate a finished file against those rules. It is published by Anthropic in the official anthropics/skills repository and loads into Claude as an Agent Skill.

What it does

• Encodes Slack's constraints for emoji and message GIFs: dimensions, FPS, color count, and duration.
• Builds and optimizes GIFs with GIFBuilder (core.gif_builder), assembling PIL frames and exporting with color reduction, duplicate removal, and emoji optimization.
• Validates output against Slack rules via core.validators (validate_gif, is_slack_ready).
• Provides easing functions (core.easing.interpolate): linear, ease_in, ease_out, ease_in_out, bounce_out, elastic_out, back_out.
• Offers frame helpers (core.frame_composer): blank frames, gradient backgrounds, and shape draws for circles, text, and stars.

How it works

You describe the GIF you want and Claude writes the animation logic using PIL ImageDraw primitives — ellipses, polygons, lines, rectangles — rather than relying on pre-made templates. It composes frames through GIFBuilder, applies easing for smooth motion, and layers animation concepts like shake, pulse, bounce, spin, fade, slide, zoom, and particle bursts. Before delivering, it can run the validators to confirm the file is Slack-ready, and apply optimization strategies (fewer frames, fewer colors, smaller dimensions, duplicate removal, emoji mode) when a smaller file is needed.

Who it's for

This skill is for Slack users, community managers, and teams who want custom animated emoji or fun message GIFs without learning a graphics pipeline. It suits anyone using Claude who would rather say "make me a bouncing taco emoji for Slack" than hand-tune Pillow code. Developers also get clean, reusable utilities to build on.

What you can build

• Custom animated Slack emoji at 128x128 under 3 seconds.
• Larger message GIFs at 480x480 for channels and threads.
• Animations combining effects: bouncing + rotating, pulsing + sliding, particle explosions, and more.
• GIFs derived from a user-uploaded image, used directly or as style inspiration.

Why it matters

Slack silently rejects or mangles GIFs that break its size and dimension rules, so getting a custom emoji to actually work is fiddly. Slack GIF Creator captures those exact constraints plus a validated build-and-optimize pipeline, letting Claude produce a file that drops straight into Slack on the first try. Because it is an official Anthropic skill, it works across Claude.ai, Claude Code, and the API, and it favors flexible PIL primitives over rigid templates so each GIF can be genuinely creative.

1. Install in Claude Code

Add the Anthropic skills marketplace, then install the example skills plugin:

/plugin marketplace add anthropics/skills
/plugin install example-skills@anthropic-agent-skills

Or add just this skill with the skills CLI:

npx skills add anthropics/skills --skill slack-gif-creator

2. Dependencies

The skill's utilities rely on Pillow, imageio, and numpy:

pip install pillow imageio numpy

3. Use it

Ask Claude for a Slack GIF, for example: "Make me a GIF of a rocket launching for Slack." Claude builds the frames, applies easing, validates against Slack's limits, and returns the file.