Plan a Mobile Feature
Walks through discovery, content prioritization, and pattern decisions, then hands back a mobile design brief an implementer can build from. Front-loads the calls before any code touches the layout.
/thumb-first plan
Mobile is its own design world.
The crossover with desktop matters, but plenty of mobile decisions have no desktop equivalent. Thumb reach. Grip changes. Bottom sheets. The iOS-vs-Material navigation chrome that’s still mid-transition. I wanted a place to make those calls deliberately, so the mobile work didn’t keep inheriting desktop assumptions.
I already had skills for layout, motion, responsive work, and intent. None of them focused on mobile. This one does.
The eight designer lenses are how the skill stays sharp on the inside. I built it because I wanted a single mobile skill I could lean on the way I lean on the others.
Plan the mobile design, or audit one.
Two modes, same posture. One front-loads the calls before code, the other catches the calls that got made silently after.
Walks through discovery, content prioritization, and pattern decisions, then hands back a mobile design brief an implementer can build from. Front-loads the calls before any code touches the layout.
/thumb-first plan
Reviews an existing mobile screen through the eight designer lenses, then surfaces the forks that got decided silently and hands back prioritized findings. Works from a screenshot, a live URL, code, or a written description.
/thumb-first audit
Works in any AI coding agent
One install command, any agent. The skill rides on the open skills protocol, so it works the same in Claude Code, Codex, Cursor, OpenCode, and 35+ others. The CLI auto-detects what you have installed and wires it up.
$npx skills add kylezantos/thumb-first#Auto-detects your agent (Claude Code, Codex, Cursor, OpenCode, 35+ more)#Then run: /thumb-first [plan | audit]
The references behind the eight lenses.
Each lens carries the positions of a working mobile designer instead of a flattened best-practices checklist. Steven Hoober on ergonomics and reach. Scott Hurff on thumb-zone cost. Luke Wroblewski on mobile-first prioritization. Josh Clark on direct manipulation and gesture discoverability. Frank Rausch on navigation taxonomy. Raluca Budiu and the rest of NN/g on empirical user behavior. Andy Allen, Sebastiaan de With, and Gavin Nelson on motion and modern craft.
Platform Canon stays close to Apple HIG and Material 3 as a moving target. iOS 26’s Liquid Glass and Material 3 Expressive are mid-transition, and Material 3 deprecated the nav drawer outright, so the skill flags chrome that’s currently unsettled instead of canonizing either side.
Thumb-First stops at the design decisions; it doesn’t write code. For the implementation it hands off to siblings: responsive-craft for responsive web layout, plus mobile-design-audit and the React Native skills for platform-specific work. The split keeps each skill from getting smeared across responsibilities.