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.
npx agentmods add skills/manhvann/codexkit/mobile-developmentnpx skills add manhvann/codexkit --skill mobile-developmentgit clone --depth 1 https://github.com/manhvann/codexkitWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00045 | $0.02193 |
| Opus 5 | $0.00023 | $0.01097 |
| Sonnet 5 | $0.00009 | $0.00439 |
| Haiku 4.5 | $0.00005 | $0.00219 |
Grade A, and why
ck:mobile-development 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 2d 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.
How it starts
The opening of the file, as written. The whole thing — 214 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Mobile Development Skill
Production-ready mobile development with modern frameworks, best practices, and mobile-first thinking patterns.
When to Use
- Building mobile applications (iOS, Android, or cross-platform)
- Implementing mobile-first design and UX patterns
- Optimizing for mobile constraints (battery, memory, network, small screens)
- Making native vs cross-platform technology decisions
- Implementing offline-first architecture and data sync
- Following platform-specific guidelines (iOS HIG, Material Design)
- Optimizing mobile app performance and user experience
- Implementing mobile security and authentication
- Testing mobile applications (unit, integration, E2E)
- Deploying to App Store and Google Play
Technology Selection Guide
Cross-Platform Frameworks:
- React Native: JavaScript expertise, web code sharing, mature ecosystem (121K stars, 67% familiarity)
- Flutter: Performance-critical apps, complex animations, fastest-growing (170K stars, 46% adoption)
Native Development:
- iOS (Swift/SwiftUI): Maximum iOS performance, latest features, Apple ecosystem integration
- Android (Kotlin/Jetpack Compose): Maximum Android performance, Material Design 3, platform optimization
See: references/mobile-frameworks.md for detailed framework comparisons
Mobile Development Mindset
The 10 Commandments of Mobile Development:
- Performance is Foundation, Not Feature - 70% abandon apps >3s load time
- Every Kilobyte, Every Millisecond Matters - Mobile constraints are real
- Offline-First by Default - Network is unreliable, design for it
- User Context > Developer Environment - Think real-world usage scenarios
- Platform Awareness Without Platform Lock-In - Respect platform conventions
- Iterate, Don't Perfect - Ship, measure, improve cycle is survival
- Security and Accessibility by Design - Not afterthoughts
- Test on Real Devices - Simulators lie about performance
- Architecture Scales with Complexity - Don't over-engineer simple apps
- Continuous Learning is Survival - Mobile landscape evolves rapidly
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 2d ago First seen · 214 lines · 45 tokens per session scan A 137eb5e97072
ck:mobile-development is a skill published in the GitHub repository manhvann/codexkit (88 stars, last pushed 3d ago), licensed MIT. It adds 45 tokens to every session and 2,193 once invoked, about $0.0002 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 2026-08-30.
Other skills, from other repositories
systematic-debugging
Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.
next-cache-components-adoption
Turn on Cache Components in a Next.js app and resolve the blocking routes it surfaces. Use when the user wants to enable, adopt, or migrate to Cache Components, flip the cacheComponents flag, work through a flood of blocking-prerender / instant validation errors, run the cache-components-instant-false codemod, or…
babysit-pr
Babysit a GitHub pull request after creation by continuously polling review comments, CI checks/workflow runs, and mergeability state until the PR is merged/closed or user help is required. Diagnose failures, retry likely flaky failures up to 3 times, auto-fix/push branch-related issues when appropriate, and keep…
imagegen
Generate or edit raster images when the task benefits from AI-created bitmap visuals such as photos, illustrations, textures, sprites, mockups, or transparent-background cutouts. Use when Codex should create a brand-new image, transform an existing image, or derive visual variants from references, and the output…
cpu-profile-analysis
Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…
next-cache-components-optimizer
Drive a Next.js route to instant navigation by setting up an agentic loop, under Cache Components / PPR, on initial load (hard navigation) and client-side navigation (soft navigation). Encode the goal as a failing @next/playwright instant() e2e and work it to green, one verified route at a time; the shipped test then…