Building a React Native app means making architecture decisions, catching performance issues before they ship, managing native dependencies, and eventually testing what you built on a real device.
No single skill covers all of that, which is why today we're releasing two Codex plugins for React Native development: Building React Native Apps and Testing React Native Apps.
npx codex-plugin add callstackincubator/agent-skills
What Codex plugins are
A Codex plugin is an installable bundle that packages multiple skills, app integrations, and MCP server configurations together. Where a skill focuses on one area, a plugin is designed around a job to be done.
Codex reads plugins from marketplace catalogs and makes them available across your projects. Once installed, skills within a plugin are progressively discovered by the agent as they become relevant. You don't have to manage them manually.
The practical difference is that a plugin can encode how skills relate to each other, not just what they individually know. That matters when the work naturally spans multiple concerns.
If you want to learn more about Codex plugins, check out the official Codex documentation here.
Plugins for React Native development
Today we're releasing two plugins around React Native development. Each one is useful on its own. They're designed to work even better in combination.
Building React Native Apps
The first plugin targets day-to-day React Native work.
It bundles:
- Best Practices from Callstack - performance-focused guidance for profiling, startup time, rendering behavior, memory issues, bundle size, and native integration tradeoffs
- Best Practices from Vercel - practical implementation guidance covering app structure, development patterns, and architectural decisions
- Upgrading React Native - structured support for version upgrades, including template diffs, dependency alignment, iOS and Android project changes, and post-upgrade verification
If you're building new features while keeping an existing app maintainable, this is the plugin to start with.
Testing React Native Apps
The third plugin combines structured test-writing guidance with device-driven verification. Under the hood, it uses agent-device, which means it's not just about test coverage. It can interact with simulators and emulators directly.
The plugin includes:
- React Native Testing - test structure, assertions, and user-focused patterns with React Native Testing Library
- Agent Device - app launch, navigation, input, screenshots, logs, performance checks, and UI inspection on simulators, emulators, and physical devices
- Dogfood - an exploratory skill that can turn your AI agent into a fully-fledged QA tester, powered by Agent Device
The combination of test-writing and device automation in a single plugin reflects how QA works in practice: you write the tests, then you verify the behavior in the running app.
Getting started
There are two ways to install the plugins today.
Option 1: Clone the repo and add it as a Codex project
Clone the repository and add it as a project in Codex.
The repo includes a marketplace configuration under .agents/plugins/marketplace.json, so Codex will automatically discover the plugins from there. You can browse and install them directly from the plugin marketplace inside Codex.
git clone https://github.com/callstackincubator/agent-skillsThen open the folder as a Codex project. The marketplace will appear with the plugins available to install.
Option 2: Use the CLI
While the Codex team works on first-class support for external marketplaces, we've built a CLI that handles the installation for you for time being. It clones the repo, reads the marketplace configuration, and installs the plugins into your Codex setup automatically.
To install globally across all your projects:
npx codex-plugin add callstackincubator/agent-skillsTo install for a specific project only:
npx codex-plugin add callstackincubator/agent-skills --projectAfter installation, the plugins appear in your Codex plugin list and are ready to enable.
Feedback
If you try the plugins, star the repo. It helps us understand what's getting used. If you're relying on a particular skill or MCP and think it belongs in a plugin, open an issue and we'll take a look.
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