Skills for Design Engineers

Skills is an open-source project by Emil Kowalski, a design engineer on the Web team at Linear who previously worked on Vercel's design team. Hosted at emilkowal.ski/skill and published under the emilkowalski/skills GitHub repository, it packages his craft sensibility into reusable SKILL.md files aimed at people working at the intersection of design and engineering. At present the repository ships two skills, both centered on motion and UI polish.

What It Is

Skills is a small, focused collection of agent-ready skill files — structured instructions that encode how Emil Kowalski thinks about interface quality. Rather than a sprawling library, it currently contains two complementary skills: one that teaches design-engineering philosophy, and one that reviews animation code against that philosophy. Both are written to be loaded by an AI assistant or read directly by a practitioner.

The Two Skills

• emil-design-eng — Encodes Emil Kowalski's full philosophy on UI polish, component design, and animation decisions. It walks through an animation decision framework (should it animate, what purpose, which easing, how fast), spring physics, component-building principles such as responsive buttons, origin-aware popovers, and interruptible toasts, plus CSS transform and clip-path techniques, gesture handling, performance rules, and accessibility. It also carries the "Sonner principles" drawn from building Sonner, his React toast component.
• review-animations — A specialized reviewer that grades motion code against a high craft bar. The skill states that approval is earned, not assumed, and defaults to flagging. It measures work against ten non-negotiable standards — justified motion, frequency-appropriate animation, responsive easing, sub-300ms UI, correct transform origin, interruptibility, GPU-only properties, accessibility, asymmetric enter/exit, and cohesion — then returns a findings table and a tiered verdict.

Shared Craft Principles

Both skills push the same opinionated defaults: animate only transform and opacity, use strong custom easing curves instead of weak built-in ones, never animate from scale(0), keep UI motion under 300ms, honor prefers-reduced-motion, and remove animation entirely from keyboard-initiated or high-frequency actions. The guiding idea, stated throughout the design-engineering skill, is that unseen details compound — taste is a trained instinct, and beauty is leverage.

Who It's For

The project is described as "Skills for Design Engineers" — practitioners who blend visual design sensibility with frontend engineering capability. Emil Kowalski's own background across Vercel and Linear gives the material a grounded, practitioner perspective rather than a purely academic one.

Current Status

The repository is publicly available on GitHub under the emilkowalski account and was last updated in mid-2026, indicating active and recent maintenance. No explicit OSI-approved license is specified in the repository, which is worth noting for anyone considering reuse or redistribution.