mobile-ui

mobile-ui is a skill for Claude Code, Codex from tmj-90/gaffer. It costs 111 tokens per session (1,482 once invoked), scanned A, original, Apache-2.0.

A set of guidelines for building mobile screens with React Native, Expo, or similar tools so they behave and look like native phone apps.

In plain words
What is it for?
Design or revise screens with safe areas, gestures, haptics, transitions, typography, launch screens, and store-readiness in mind.
Why use it?
It helps avoid the appearance and performance problems of a mobile website wrapped inside an app.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/tmj-90/gaffer/mobile-ui
Any agent
npx skills add tmj-90/gaffer --skill mobile-ui
Clone the repo
git clone --depth 1 https://github.com/tmj-90/gaffer

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for mobile-ui

README.md
[![agentmods](https://agentmods.dev/badge/skills/tmj-90/gaffer/mobile-ui.svg)](https://agentmods.dev/skills/tmj-90/gaffer/mobile-ui)
Your own site
<a href="https://agentmods.dev/skills/tmj-90/gaffer/mobile-ui"><img src="https://agentmods.dev/badge/skills/tmj-90/gaffer/mobile-ui.svg" alt="Measured on agentmods" height="20"></a>
Per session 111 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,482 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00111 $0.01482
Opus 5 $0.00056 $0.00741
Sonnet 5 $0.00022 $0.00296
Haiku 4.5 $0.00011 $0.00148

Measured 4d ago against content hash 9bba515b97e0, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

mobile-ui scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

runner/skills/mobile-ui/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Build store-credible native-feel mobile UI

Change the skin, never the skeleton. Build mobile UI that clears a native-feel bar and a store-readiness bar — without touching gameplay, navigation routes, state, scoring, or business logic. Where a redesign implies a structural change ("this should be a sheet, not a modal"), flag it as a proposal; do not silently implement it.

The three non-negotiable bars

A "premium" mobile surface must clear all three at once — failing any one ships as not-premium regardless of the others.

  1. Native feel. Every hybrid/RN screen reads as a mobile website until deliberately de-websified. Tells to close: centred modals (→ bottom sheets), fade transitions (→ slide/shared-element), missing swipe-back and hardware-back handling, no haptics on primary taps, fonts flashing, wrong scroll bounce, ignored safe-area insets, default launch screen.
  2. Maturity (indie → store-credible). Tidying a plateau makes the plateau more visible. Recommit: real type scale, brand chrome (not generic), activated margins, ambient life, and one named hero detail per screen — the deliberate moment the user remembers.
  3. Store readiness. Most "wouldn't get approved" intuition is a finite checklist: tap targets ≥ 44pt, privacy/permission strings present, real launch screen, Dynamic Type / large-text support, working hardware back (Android), opposite colour scheme, no placeholder content.

Steps

  1. Read the lore + brand/tokens first. search_lore (Memory MCP) and any BRAND.md/DESIGN.md/tokens file. If a brand/design system exists, extend it in its idiom (Brand-Respecting Mode) — audit + close gaps; do not re-pitch the aesthetic. Confirm the stack (RN/Expo or React + Capacitor) and match its component conventions.
  2. Audit the screen against the three bars: score native-feel per item, diagnose maturity, pre-screen store-rejection triggers. Note gameplay/logic surfaces to leave alone.
  3. Respect safe areas. Use the safe-area insets (react-native-safe-area-context / the env-inset equivalent) for top/bottom/notch; never hardcode status-bar heights.
  4. Gestures + navigation feel native. Swipe-back, hardware back (Android), bottom sheets over centred modals, slide/shared-element transitions over fades. Keep the navigation routes and actions exactly as they are.
  5. Haptics + sound hooks on primary interactions (selection, confirm, error) via the platform haptics API — subtle, consistent, behind a tokenised hook.
  6. Tokens drive presentation — colour, type scale, spacing, motion, radius. No raw hex or magic numbers in components; scrolls hide scrollbars, use momentum, and disable global pull-to-refresh except where intended.
  7. Performance: keep the main interaction loop at 60fps; animate on the native driver (useNativeDriver: true / Reanimated worklets); virtualise long lists (FlatList/ FlashList); avoid layout thrash and oversized images.
  8. Verify + evidence. Run the repo's tests + lint; a migration ends green — a failing gameplay test means logic changed (roll back, never edit the test to pass). Add tests for new visual contracts (component states, screen smoke tests). Record test_output via record-evidence and submit for review.

Read the full file on GitHub · 96 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 96 lines · 111 tokens per session scan A 9bba515b97e0

Subscribe to this mod's changes

mobile-ui is a skill published in the GitHub repository tmj-90/gaffer (2 stars, last pushed 4d ago), licensed Apache-2.0. It adds 111 tokens to every session and 1,482 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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