Expo App Design
Build native-feeling Expo screens — Apple HIG styling, semantic colors, and native UI patterns.
eas-observe
EAS service (paid). Use for anything related to EAS Observe - adding `expo-observe` to an Expo project (AppMetricsRoot/ObserveRoot HOC, markInteractive, the useObserve hook, the Expo Router / React Navigation integrations for per-route metrics, and user-defined events via `Observe.logEvent`), querying via the EAS CLI (`eas observe:metrics-summary`, `observe:metrics`, `observe:routes`, `observe:events`, `observe:versions`), or interpreting the resulting metrics (cold/warm launch, TTR, TTI, navigation cold/warm TTR, update download, and the TTI frameRate params for triaging slow startups).
Full skill instructions
EAS service - costs apply. EAS Observe is an Expo Application Services product. The free EAS plan allows up to 10,000 monthly active users, with a limited set of features; higher usage requires a paid subscription. For details, see https://expo.dev/pricing#plan-features.
EAS Observe tracks startup, navigation, and custom-event performance from production Expo apps. It needs a development or production build — the native library is not in Expo Go.
Source of truth: https://docs.expo.dev/eas/observe/ — always consult the canonical docs when API details matter, especially get-started, configuration, integrations, and the metrics reference. EAS Observe is evolving; this skill's references are written to stay accurate but may lag the docs.
The four reference files in ./references/ cover what people typically need this skill for:
./references/setup.md. Install, wrap the root layout (AppMetricsRoot on SDK 55, ObserveRoot on SDK 56+), mark the app interactive (global markInteractive() on SDK 55, the useObserve() hook or <ObserveInteractiveMarker /> on SDK 56+), optional per-route navigation metrics through the Expo Router / React Navigation integrations, user-defined events via Observe.logEvent (SDK 56+), error reporting, and runtime configuration (sampling, dispatch, environments, custom endpoint)../references/queries.md. The six eas observe:* commands — metrics-summary, metrics, routes, events, session, versions — with flags, metric aliases, table layouts, JSON shapes, and common workflows../references/metrics.md. Target thresholds per metric, what the automatic TTI params mean (frameRate.*, device.*, network.*), and diagnostic patterns for telling slow-but-smooth startup apart from main-thread contention, hard blocks, or throttled devices../references/third-party.md. For package authors only (SDK 57+): optional peer dependency, config declaration merging, Observe.registerIntegration(), and event naming.Verified against eas-cli 21.8.0 and expo-observe 57.0.9. Trust this skill's references over the docs on these points, but re-check with --help and the installed package before relying on them:
observe:routes and observe:session.nav_cold_ttr, nav_warm_ttr, and nav_tti. There are no bare cold_ttr / warm_ttr aliases in the CLI.--sort <slowest|fastest|newest|oldest>. There is no --order flag.ObserveErrorBoundary, Observe.reportError, and configure({ errorHandlingEnabled }) are exported but undocumented. Observe still has no crash reporting; use Sentry or BugSnag for that.If you encounter errors, misleading or outdated information in this skill, report it so Expo can improve:
npx --yes submit-expo-feedback@latest --category skills --subject "eas-observe" "<actionable feedback>"
Only submit when you have something specific and actionable to report. Include as much relevant context as possible. If an AI agent repeatedly failed or the user had to take over an Expo task, load the expo-skill-feedback skill and follow its eval-candidate flow instead of reusing the command above.
Build native-feeling Expo screens — Apple HIG styling, semantic colors, and native UI patterns.
expo brownfield
Framework (OSS). Navigation and routing for Expo Router. Covers file-based routes, groups and dynamic routes, folder organization, Link with previews and context menus, native Stack, page titles, modals and form sheets, NativeTabs, headers and toolbars, and header search bars.
Safely upgrade Expo SDK versions with migration guidance and breaking change resolution.
Framework (OSS). Use when implementing or debugging ANY network request, API call, or data fetching. Covers fetch API, React Query, SWR, error handling, caching, offline support, and Expo Router data loaders (`useLoaderData`).
Framework (OSS). Expo's official example projects - the expo/examples repo of ~70 `with-*` integrations (Stripe, Clerk, Supabase, OpenAI, maps, Reanimated, SQLite, Skia, NativeWind, and more). Use when integrating a third-party library or service into an existing Expo app and you want the canonical, version-matched pattern to adapt, or when scaffolding a new project from one with `npx create-expo --example`.
Deploy Expo apps to production with EAS Build and app store submission workflows.
Evaluate Expo skills in this repo end-to-end - trigger accuracy, generated code quality, and runtime screenshots on iOS simulator and Android emulator via Expo Go (web optional). Use when the user wants to eval an Expo skill, test that a skill produces working code, benchmark a skill with device screenshots, or verify a skill's output renders correctly.
EAS service (paid). Helps understand and write EAS workflow YAML files for Expo projects. Use this skill when the user asks about CI/CD or workflows in an Expo or EAS context, mentions .eas/workflows/, or wants help with EAS build pipelines or deployment automation.
Framework (OSS). Use Expo DOM components to run web code in a webview on native and as-is on web. Migrate web code to native incrementally. For the end-to-end migration of a whole web app, use the expo-web-to-native skill.
EAS service (paid). Run and control a user's app on a remote iOS/Android simulator hosted on EAS cloud. Read before running any `eas simulator:*` commands - it has the current syntax for this experimental API. Use whenever the user needs a simulator they can't run locally - 'run my app on a cloud simulator', 'use eas simulator to run/install/screenshot my app', 'I'm on Linux/Cursor and need an iOS device', 'no sim on this box / headless CI', 'let an agent click through my app and screenshot it', 'test my dev build on a remote sim with live reload', 'stream a sim to my browser' - even when they don't say 'EAS Simulator' or 'cloud'. On a host WITHOUT a local simulator (Linux, CI, cloud sandbox) it's the default; on macOS, do NOT auto-trigger for a plain 'run on the simulator' - use it only for a cloud/remote/shareable sim, an iOS version they lack, or an agent-driven session. NOT for local sims (expo run:ios, Xcode, Android Studio), EAS Build/Update, web preview, or physical devices.
Framework (OSS). Add an iOS App Clip target to an Expo app. Use when the user mentions App Clip, AASA, apple-app-site-association, appclips, smart app banner, or wants to ship a lightweight iOS Clip invoked from a URL alongside their parent app.
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