This gives you practical implementations of Disney's 12 animation principles directly in After Effects, with expressions you can copy and paste. You get code snippets for squash and stretch, delay expressions for follow-through, overshoot formulas for exaggeration, and timing charts that map frame counts to animation feels. It's genuinely useful if you're animating but never formally studied these principles, or if you know them conceptually but need the technical AE implementation. The expression library alone (wiggle, bounce, loop) saves you from hunting Stack Overflow. Covers everything from bezier easing to motion paths to export formats like Lottie. More reference sheet than tutorial, which is exactly what you want mid-project.
npx skills add https://github.com/dylantarre/animation-principles --skill after-effects