Expo Skills

EAS Observe collects app performance telemetry and custom events from Expo apps. You can access this data using five primary CLI commands:

• eas observe:metrics-summary: Provides per-version statistical aggregates (median, p90, etc.) for app-startup performance metrics.
• eas observe:metrics: Provides individual performance metric samples, ordered by value or timestamp (paginated).
• eas observe:routes: Provides per-route statistical aggregates for navigation metrics (Cold TTR, Warm TTR, Nav TTI).
• eas observe:events: Provides custom events emitted via logEvent. You can view a summary of event names, all events, or filter by a specific event name.
• eas observe:versions: Displays the app version hierarchy, including build numbers, OTA update IDs, and event counts.

EAS Observe is a paid Expo Application Services product that tracks startup, navigation, and custom-event performance from production Expo apps. It allows you to monitor metrics such as cold/warm launch, Time to Render (TTR), Time to Interactive (TTI), navigation performance, update downloads, and more.

Note: This is a paid service. Ingesting and querying production metrics counts against your plan's event/usage allowance. Review the Expo pricing page before enabling it in production.

React 19 is included in Expo SDK 54 and introduces several new features:

• Actions: Functions that handle async transitions.
• useOptimistic: For managing optimistic UI updates.
• useFormStatus: For accessing form submission state (web).
• Document Metadata: Native support for <title> and <meta> tags (web).

Expo Skills are specialized knowledge modules used by agents and developers to handle specific tasks within the Expo ecosystem. They are categorized into two main types:

1. Framework (OSS): Free, open-source Expo SDK and React Native skills. These focus on development, navigation, UI, data fetching, and module creation.
2. EAS service (paid): Skills centered around paid Expo Application Services (EAS). These focus on production builds, hosting, CI/CD workflows, observability, and remote simulators.

Skills are discovered by agents via a SKILL.md file located exactly one level deep in the skills/ directory (e.g., skills/<skill-name>/SKILL.md).

The expo-web-to-native skill provides a framework for migrating an existing web React app (Next.js, Vite, CRA, etc.) to a native iOS/Android app using Expo.

Key Principles:

• Migrate, don't rewrite: Use a 'strangler fig' approach, standing up a native shell and replacing web screens with native ones incrementally.
• Ship on day one: Use the expo-dom skill to run the entire web UI inside a native shell immediately.
• Strangle by value: Nativize high-value/hot screens first; leave less critical screens in a webview to save on runtime overhead.
• Nativize means redesign: Do not just reskin web layouts. Use @expo/ui to render real SwiftUI/Compose components so the app feels native to the OS.
• Verify by running: A successful build does not guarantee a working UI. Always verify content and behavior by running the app on a device/simulator.

The expo-data-fetching skill is a framework for implementing or debugging any networking work, including API requests, data fetching, caching, or network debugging. Use this skill when implementing API requests, setting up data fetching libraries (React Query, SWR), using Expo Router data loaders, debugging network failures, implementing caching, handling offline scenarios, managing authentication, or configuring API URLs via environment variables.

Preference: Avoid axios; prefer the standard fetch API.

The eas-workflows skill is designed to help developers write, edit, and validate EAS CI/CD workflow YAML files for Expo projects.

Important Note: EAS is a paid service. Each workflow job consumes build/compute minutes according to your Expo plan. Jobs that build or submit applications also require paid Apple Developer and Google Play accounts. Review expo.dev/pricing before triggering runs.

EAS Simulator is a paid service that runs remote iOS simulators or Android emulators on Expo Application Services (EAS) cloud infrastructure. It is designed for environments that cannot run simulators locally (e.g., Linux, CI, or cloud-based AI agents like Cursor Cloud) or when a user needs to test a specific iOS version they lack on a Mac.

Important Constraints:

• Not for local simulators: Do not use this for expo run:ios, Xcode, or Android Studio.
• Not for EAS Build/Update: This is for running/interacting with a simulator, not for building binaries or deploying updates.
• Cost: This is a paid service. Sessions use your plan's compute allowance.
• Experimental: The simulator:* commands are experimental. Always use npx --yes eas-cli@latest to ensure you have the required version (≥ 20.3.0).

While Skills provide the knowledge (how to do things), the Expo MCP (Model Context Protocol) server provides the capability (actually doing the work).

The MCP server allows an agent to:

• Read the latest Expo documentation on demand.
• Install compatible dependencies using npx expo install.
• Trigger and monitor EAS builds and workflows.
• Pull crash data from TestFlight.
• Screenshot a running app in the simulator.

If you use the Claude Code or Codex plugins, the MCP configuration is bundled and wired up automatically. For other agents, you must follow the Expo MCP setup guide.