Callstack Agent Skills is a collection of instructions that gives AI coding assistants practical knowledge for building React Native applications. Developers use it for app development, performance, navigation, testing, CI, device automation, and migrations to React Native. The catalogue entries are the project's skills, rules, and instructions for compatible coding assistants.
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.
git clone --depth 1 https://github.com/callstackincubator/agent-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/rules/callstackincubator/agent-skills/react-native-best-practices)<a href="https://agentmods.dev/rules/callstackincubator/agent-skills/react-native-best-practices"><img src="https://agentmods.dev/badge/rules/callstackincubator/agent-skills/react-native-best-practices/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/rules/callstackincubator/agent-skills/react-native-best-practices"><img src="https://agentmods.dev/badge/rules/callstackincubator/agent-skills/react-native-best-practices.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00000 | $0.00200 |
| Opus 5.5 | $0.00000 | $0.00080 |
| Sonnet 5.5 | $0.00000 | $0.00040 |
| Haiku 4.5 | $0.00000 | $0.00020 |
Grade A, and why
react-native-best-practices 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 1mo 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.
What it actually says
React Native performance
When editing matched files for React Native or Expo performance work:
- Open
skills/react-native-best-practices/SKILL.md(or the local file if this repo is in the workspace) for problem → reference routing. - Profile before suggesting memoization hooks or micro-optimizations.
- Prefer concrete references under
skills/react-native-best-practices/references/(lists, bundle, native, JS) over generic advice.
If skills/ is not in the workspace, tell the user to add this repository’s skills/ content per the upstream README.
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.
- 1mo ago First seen · 16 lines · 0 tokens per session scan A f9bd99ffdb4f
react-native-best-practices is a cursor rule published in the GitHub repository callstackincubator/agent-skills (1,672 stars, last pushed 7d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 200 tokens. 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 cursor rules, from other repositories
expo
Expo Router, NativeWind, and mobile conventions.
expo-development
React Native and Expo development guidelines, commands, and patterns.
library-conventions
React Native library conventions for this starter. Apply when creating or editing components, hooks, types, or tests in src/.
react-native-polyfills
Required polyfills and configuration for MetaMask Connect SDK in React Native — import order, Buffer, window, Event/CustomEvent, metro config, and persistence.
mobile-feature-architecture
Hybrid feature-first structure for Expo apps.
react-native
A set of rules for building mobile apps with TypeScript, React Native, Expo, and mobile interface components. React Native lets developers create native mobile apps with React, while Expo provides supporting tools.