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 skills add happycapy-ai/Happycapy-skills --skill mobile-app-developergit clone --depth 1 https://github.com/happycapy-ai/Happycapy-skillsWrote 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.
[](https://agentmods.dev/skills/happycapy-ai/happycapy-skills/mobile-app-developer)<a href="https://agentmods.dev/skills/happycapy-ai/happycapy-skills/mobile-app-developer"><img src="https://agentmods.dev/badge/skills/happycapy-ai/happycapy-skills/mobile-app-developer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/happycapy-ai/happycapy-skills/mobile-app-developer"><img src="https://agentmods.dev/badge/skills/happycapy-ai/happycapy-skills/mobile-app-developer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high Privilege Escalation · line 46 Code accesses credential files (SSH keys, AWS credentials, etc.). This could indicate credential theft attempts.Fix: Remove references to credential paths. Use environment variables or secrets managers. For docs, use placeholder paths (e.g., /path/to/config). Never load .env or token files in production code paths.
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00121 | $0.01245 |
| Opus 5 | $0.00060 | $0.00622 |
| Sonnet 5 | $0.00024 | $0.00249 |
| Haiku 4.5 | $0.00012 | $0.00125 |
Grade A, and why
mobile-app-developer scanned grade A with 1 finding 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 11d 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl --version # for fetching build logs How it starts
The opening of the file, as written. The whole thing — 106 lines — stays where its author put it; the contents beside it link to each section on GitHub.
mobile-app-developer
End-to-end playbook for shipping an Expo / React Native app — from scaffolding to TestFlight / Play Store — fully automated from a Linux sandbox.
When to Trigger
Trigger this skill when the user wants to:
- Scaffold or modify a React Native / Expo project
- Run / test / debug the app locally (Expo Go, dev client, simulator)
- Generate a web preview page with phone frame + Expo Go QR code
- Configure EAS Build (cloud build) for iOS or Android
- Publish to TestFlight (iOS internal testing) or Google Play Internal Testing
- Submit to App Store / Play Store public release
- Set up ASC API Key auth (bypass Apple 2FA)
- Replace icons / splash screens for store compliance
- Diagnose EAS build failures (peer deps, lock files, credentials, fingerprint, etc.)
Do NOT trigger for: pure native iOS/Android (no Expo), Flutter, Cordova/Capacitor, KMP/Compose Multiplatform.
Skill Layout
This skill is split into focused documents. Read the relevant one(s) on demand — do NOT preload all.
| File | Read when… |
|---|---|
development.md |
Setting up project, installing deps, configuring app.json, preparing icons/splash, running on simulator/device, fixing peer-dep / lock-file errors, managing env vars / secrets |
publishing.md |
Configuring eas.json submit profile, ASC API Key / Play Service Account, running build + submit, diagnosing submit failures, App Store / Play Store metadata checklists |
preview.md |
Generating a web preview page with phone frame + Expo Go QR code. Uses Expo Web (react-native-web) static export for browser preview and Expo dev server for real-device QR scanning |
If the user's task spans multiple (e.g. "build a new Expo app and ship it to TestFlight"), read development.md first, then publishing.md.
Default Tech Stack
| Layer | Choice |
|---|---|
| Framework | Expo (latest stable — check https://docs.expo.dev/versions/latest/ before scaffolding) |
| Build / Distribution | EAS Build + EAS Submit (Expo cloud) |
| Auth (Apple) | App Store Connect API Key (.p8) — bypasses 2FA |
| Auth (Google) | Play Console Service Account JSON |
| Auth (Expo) | Personal Access Token via EXPO_TOKEN |
What ships with it
3 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.
- 11d ago First seen · 106 lines · 121 tokens per session scan A 029882356ab6
mobile-app-developer is a skill published in the GitHub repository happycapy-ai/Happycapy-skills (139 stars, last pushed 7d ago), licensed MIT. It adds 121 tokens to every session and 1,245 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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