React Native & Expo Router Gemini System Prompt

Production-grade architectural rulebook for React Native & Expo Router. Engineered to eliminate LLM hallucinations, enforce strict deterministic conventions, and prevent architectural drift across Cursor IDE, Claude Code CLI, and autonomous multi-agent pipelines.

Target Path
prompts/gemini-system-instructions.json
Execution Scope
Project Context
Specification Format
Markdown / Config
AI Tool Support
Universal AI Assistants
02 / DRIFT ANALYSIS & VALUE PROPOSITION

Failure Patterns Prevented for React Native & Expo Router

Without This Rule (Default LLM Behavior)Vulnerable

Modern React Native uses Expo Router v3/v4 with file-based layout groups (app/(tabs)), typed routes, and React Native New Architecture (Fabric/TurboModules). LLMs constantly generate obsolete React Navigation Stack wrappers, deprecated AsyncStorage imports, and un-safe-area layout overflows.

Hallucination Symptoms
  • Invokes deprecated or removed APIs from older model training weights
  • Generates conflicting configuration files and invalid imports
  • Silently drops type-safety, boundaries, or transaction isolation
With This Rule (Guaranteed Invariants)Deterministic
Use Expo Router file-based filesystem routing (app/_layout.tsx, app/(tabs)/index.tsx); ban legacy React Navigation container boilerplate.
Enforce react-native-safe-area-context (useSafeAreaInsets or SafeAreaView) for all top-level mobile screen boundaries.
Use modern Expo SDK native modules (expo-image, expo-secure-store, expo-crypto) instead of unmaintained bare native packages.
Optimize for React Native New Architecture (Fabric renderer): avoid synchronous layout measurements in render passes.
Always test cross-platform styling on both iOS and Android (e.g. elevation vs shadowColor, notch handling).
03 / VERIFIED CODE PATTERNS

Code Standards: Anti-Pattern vs Verified Implementation

Discouraged Anti-Pattern
// Discouraged: Missing safe-area insets, slow standard Image component, obsolete navigation prop
export default function BadProfile({ navigation }: any) {
  return (
    <div style={{ marginTop: 50 }}>
      <img src="avatar.png" />
      <button onClick={() => navigation.navigate("Home")}>Go</button>
    </div>
  );
}
Verified Production Standard
import { View, Text, StyleSheet } from "react-native";
import { Image } from "expo-image";
import { useSafeAreaInsets } from "react-native-safe-area-context";

export default function ProfileScreen() {
  const insets = useSafeAreaInsets();
  return (
    <View style={[styles.container, { paddingTop: insets.top, paddingBottom: insets.bottom }]}>
      <Image
        source={{ uri: "https://example.com/avatar.png" }}
        style={styles.avatar}
        contentFit="cover"
        transition={200}
      />
      <Text style={styles.title}>User Profile</Text>
    </View>
  );
}

const styles = StyleSheet.create({
  container: { flex: 1, backgroundColor: "#fff", paddingHorizontal: 16 },
  avatar: { width: 80, height: 80, borderRadius: 40 },
  title: { fontSize: 20, fontWeight: "600", marginTop: 12 },
});
04 / REPOSITORY PLACEMENT & 3-STEP TERMINAL INSTALLATION

How to Install React Native & Expo Router Gemini System Instructions via Terminal

1

Step 1: Open Project Directory & Verify Target Placement

Open your terminal and navigate to your project root folder where the prompts/gemini-system-instructions.json file will reside. Ensure the file is placed at the exact path below relative to your project root so the AI engine automatically loads it:

prompts/gemini-system-instructions.json
2

Step 2: Fetch Rule File via Terminal Command

Run curl, PowerShell, or wget to stream the rule directly from the DevScratchpad raw API endpoint and write it to prompts/gemini-system-instructions.json:

Terminal One-Liner Install

Run directly in your project root to stream and write this rule file with one command.

Raw API Stream
$mkdir -p "prompts" && curl -fsSL "https://www.devscratchpad.tech/api/raw/gemini-prompts/react-native-expo" -o "prompts/gemini-system-instructions.json"
3

Step 3: Verify and Activate with AI Agent

Launch your AI coding assistant (Universal AI Assistants). The assistant will automatically discover prompts/gemini-system-instructions.json in your repository and apply the architectural guardrails, type constraints, and verification protocols during code generation.

05 / ROUTE DIRECTORY & CROSS-TOOLING
Format Pillar HubComprehensive Manual

Gemini API System Instructions Generator

Inspect the complete specification manual, glob patterns, directory rules, and all available presets in our central directory.

/gemini-prompts Directory
06 / RECOMMENDED OFFLINE DEVELOPER TOOLS

Pair With React Native & Expo Router Client-Side Utilities

100% private, browser-based utilities to test, format, and inspect code generated by your AI rules.

View All 28 Tools

Migrating from Legacy .cursorrules or CLAUDE.md?

Use our free, offline converter to transform monolithic rulebooks into modular Cursor .mdc, Claude SKILL.md, and Windsurf Cascade rules.

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07 / FREQUENTLY ASKED QUESTIONS

Technical FAQ: React Native & Expo Router AI Rulebooks

Does this support Expo Router v3 and v4?

Yes, it enforces typed routes, layout groups (tabs), and useLocalSearchParams.

Why use expo-image over React Native Image?

expo-image provides hardware decoding, progressive loading, blurhash previews, and superior memory caching on iOS and Android.