Implements an accepted incremental brownfield migration from native iOS or Android to React Native or Expo using @callstack/react-native-brownfield. Use after the brownfield path has been selected, when setting up the integration, packaging XCFramework or AAR artifacts, or adding React Native surfac

Migrating to React Native Use this skill only after the decision to adopt brownfield migration has been made. When the user is still choosing between brownfield, greenfield, a checkpoint based path, defer, or no migration, use [assess react native migration](../assess react native migration/SKILL.md) first. Overview Prescriptive workflow for incremental adoption of React Native in existing native apps using @callstack/react native brownfield , from initial setup through phased host integration. Expo track Bare React Native track Use one track per task unless the user explicitly asks for migration or comparison. Migration Strategy Use this strategy for brownfield migration planning and execution: 1. Assess app state and select Expo or bare path. 2. Perform initial setup with @callstack/react native brownfield . 3. Package RN artifacts ( XCFramework / AAR ) from the RN source app. 4. Integrate one RN surface into the host app and validate startup/runtime. 5. Repeat integration by feature/screen for incremental rollout. Agent Guardrails (Global) Apply these rules across all reference files: 1. Select one path first (Expo or bare) and do not mix steps. 2. Use placeholders from the docs ( <framework target name , <android module name , <registered module name ) and resolve from project files. 3. Validate each packaging command before moving to host integration. 4. Prefer official docs for long platform snippets and CLI option details. 5. Keep host apps isolated from direct React Native APIs when possible (facade approach). 6. For startup/runtime verification, use agent device to open the host app, navigate to the RN surface, capture snapshots/screenshots, and collect device evidence. If it is missing and verification needs it, install it through the environment's approved/trusted path or ask the user to install or enable it. Canonical Docs [Quick Start](https://oss.callstack.com/react native brownfield/docs/getting started/quick start.md) [Expo Integration](https://oss.callstack.com/react native brownfield/docs/getting started/expo.md) [iOS Integration](https://oss.callstack.com/react native brownfield/docs/getting started/ios.md) [Android Integration](https://oss.callstack.com/react native brownfield/docs/getting started/android.md) [Brownfield CLI](https://oss.callstack.com/react native brownfield/docs/cli/brownfield.md) [Guidelines](https://oss.callstack.com/react native brownfield/docs/guides/guidelines.md) [Troubleshooting](https://oss.callstack.com/react native brownfield/docs/guides/troubleshooting.md) Path Selection Gate (Must Run First) Before selecting any reference file, classify the project: 1. If no React Native app exists yet, use Expo creation path: [expo create app.md][expo create app] [expo quick start.md][expo quick start] 2. If React Native app exists, inspect package.json and app.json : Expo if expo is present or Expo plugin workflow is requested. Bare RN if native folders and direct RN CLI workflow are used without Expo path requirements. 3. If still unclear, ask one disambiguation question. 4. Continue with exactly one path. When to Apply Reference this package when: Implementing an accepted incremental migration from native only apps to React Native or Expo Creating brownfield integration flows for Expo or bare React Native projects Performing initial setup with @callstack/react native brownfield Generating iOS XCFramework artifacts from a React Native app Generating and publishing Android AAR artifacts from a React Native app Integrating generated artifacts into host iOS/Android apps Quick Reference File Description [quick start.md][quick start] Shared preflight and mandatory path selection gate [expo create app.md][expo create app] Scaffold a new Expo app before Expo brownfield setup [expo quick start.md][expo quick start] Expo plugin setup and packaging readiness [expo ios integration.md][expo ios integration] Expo iOS packaging and host startup integration [expo android integration.md][expo android integration] Expo Android packaging, publish, and host integration [bare quick start.md][bare quick start] Bare React Native baseline setup [bare ios xcframework generation.md][bare ios xcframework generation] Bare iOS XCFramework generation [bare android aar generation.md][bare android aar generation] Bare Android AAR generation and publish [bare ios native integration.md][bare ios native integration] Bare iOS host integration [bare android native integration.md][bare android native integration] Bare Android host integration Problem Skill Mapping Problem Start With Need migration path decision first [assess react native migration](../assess react native migration/SKILL.md) Need Expo vs bare path decision [quick start.md][quick start] Need to create a new Expo app for brownfield [expo create app.md][expo create app] Need Expo brownfield setup and plugin wiring [expo quick start.md][expo quick start] Need Expo iOS brownfield integration [expo ios integration.md][expo ios integration] Need Expo Android brownfield integration [expo android integration.md][expo android integration] Need bare RN baseline setup [bare quick start.md][bare quick start] Need bare RN iOS XCFramework generation [bare ios xcframework generation.md][bare ios xcframework generation] Need bare RN Android AAR generation/publish [bare android aar generation.md][bare android aar generation] Need bare RN iOS host integration [bare ios native integration.md][bare ios native integration] Need bare RN Android host integration [bare android native integration.md][bare android native integration] Related Skills [Assess React Native migration](../assess react native migration/SKILL.md) before selecting the migration path. [quick start]: references/quick start.md [expo create app]: references/expo create app.md [expo quick start]: references/expo quick start.md [expo ios integration]: references/expo ios integration.md [expo android integration]: references/expo android integration.md [bare quick start]: references/bare quick start.md [bare ios xcframework generation]: references/bare ios xcframework generation.md [bare android aar generation]: references/bare android aar generation.md [bare ios native integration]: references/bare ios native integration.md [bare android native integration]: references/bare android native integration.md

react-native-brownfield-migration