diff --git a/packages/client-android/App.tsx b/packages/client-android/App.tsx
index 8144162..e0849f6 100644
--- a/packages/client-android/App.tsx
+++ b/packages/client-android/App.tsx
@@ -2,14 +2,21 @@ import { StatusBar } from 'expo-status-bar';
 import { useState } from 'react';
 import {
   StyleSheet, Text, View, TextInput, TouchableOpacity,
-  ScrollView, Switch,
+  ScrollView, Switch, FlatList, KeyboardAvoidingView, Platform,
 } from 'react-native';
 import { DEFAULT_GATEWAY_CONFIG } from '@yuzu-gca/shared';
 
-/** U-001: Settings Page for Yuzu GCA Android Client */
+/** Android Client: Chat + Settings + Connection */
+
+type Msg = { role: 'user' | 'assistant'; text: string; ts: number };
 
 export default function App() {
-  const [tab, setTab] = useState<'settings' | 'device' | 'connection'>('settings');
+  const [tab, setTab] = useState<'chat' | 'settings' | 'device' | 'connection'>('chat');
+
+  // Chat state
+  const [messages, setMessages] = useState<Msg[]>([]);
+  const [input, setInput] = useState('');
+  const [sending, setSending] = useState(false);
 
   // Settings state
   const [gatewayUrl, setGatewayUrl] = useState(DEFAULT_GATEWAY_CONFIG.url);
@@ -21,134 +28,206 @@ export default function App() {
   // Connection state
   const [connStatus, setConnStatus] = useState<'disconnected' | 'connecting' | 'connected' | 'error'>('disconnected');
 
+  /** Send chat message to Gateway */
+  const sendMessage = async () => {
+    const text = input.trim();
+    if (!text || sending) return;
+    const userMsg: Msg = { role: 'user', text, ts: Date.now() };
+    setMessages(prev => [...prev, userMsg]);
+    setInput('');
+    setSending(true);
+
+    try {
+      const resp = await fetch(`${gatewayUrl}/chat`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ message: text }),
+        signal: AbortSignal.timeout(30000),
+      });
+      if (!resp.ok) throw new Error(`HTTP ${resp.status}`);
+      const data = await resp.json() as { reply?: string; error?: string };
+      const aiMsg: Msg = {
+        role: 'assistant',
+        text: data.reply ?? data.error ?? 'No response',
+        ts: Date.now(),
+      };
+      setMessages(prev => [...prev, aiMsg]);
+    } catch (e: any) {
+      setMessages(prev => [...prev, {
+        role: 'assistant',
+        text: `Error: ${e.message}`,
+        ts: Date.now(),
+      }]);
+    } finally {
+      setSending(false);
+    }
+  };
+
+  /** Connect/disconnect toggle */
+  const toggleConnection = () => {
+    setConnStatus(prev => {
+      if (prev === 'disconnected' || prev === 'error') return 'connecting';
+      return 'disconnected';
+    });
+  };
+
+  // ── Render ──────────────────────────────────────────────
+
   return (
-    <View style={styles.container}>
+    <KeyboardAvoidingView style={styles.root} behavior={Platform.OS === 'ios' ? 'padding' : undefined}>
       <StatusBar style="light" />
 
       {/* Header */}
-      <Text style={styles.title}>Yuzu GCA</Text>
-      <Text style={styles.subtitle}>Settings</Text>
+      <View style={styles.header}>
+        <Text style={styles.title}>Yuzu GCA</Text>
+        <View style={[styles.statusDot, styles[`dot_${connStatus}` as keyof typeof styles]]} />
+      </View>
 
       {/* Tabs */}
       <View style={styles.tabBar}>
-        {(['settings', 'device', 'connection'] as const).map(t => (
+        {(['chat', 'settings', 'device', 'connection'] as const).map(t => (
           <TouchableOpacity key={t} onPress={() => setTab(t)} style={[styles.tab, tab === t && styles.tabActive]}>
             <Text style={[styles.tabText, tab === t && styles.tabTextActive]}>
-              {t === 'settings' ? 'Gateway' : t === 'device' ? 'Device' : 'Connection'}
+              {t === 'chat' ? 'Chat' : t === 'settings' ? 'Gateway' : t === 'device' ? 'Device' : (connStatus === 'connected' ? '🟢' : '⚫')}
             </Text>
           </TouchableOpacity>
         ))}
       </View>
 
-      <ScrollView style={styles.body}>
-        {tab === 'settings' && (
-          <>
-            {/* Gateway URL */}
-            <Text style={styles.label}>Gateway URL</Text>
+      {/* ── Chat Tab ── */}
+      {tab === 'chat' && (
+        <View style={styles.chatContainer}>
+          <FlatList
+            data={messages}
+            keyExtractor={(_, i) => String(i)}
+            style={styles.chatList}
+            renderItem={({ item }) => (
+              <View style={[styles.bubble, item.role === 'user' ? styles.bubbleUser : styles.bubbleAI]}>
+                <Text style={styles.bubbleRole}>{item.role === 'user' ? 'You' : 'GCA'}</Text>
+                <Text style={styles.bubbleText}>{item.text}</Text>
+              </View>
+            )}
+            ListEmptyComponent={
+              <Text style={styles.emptyText}>Send a message to control your devices via AI</Text>
+            }
+          />
+          <View style={styles.inputBar}>
             <TextInput
-              style={styles.input}
-              value={gatewayUrl}
-              onChangeText={setGatewayUrl}
-              placeholder="http://localhost:3000"
+              style={styles.chatInput}
+              value={input}
+              onChangeText={setInput}
+              placeholder="Type a command..."
               placeholderTextColor="#475569"
-              autoCapitalize="none"
-              keyboardType="url"
+              onSubmitEditing={sendMessage}
+              returnKeyType="send"
             />
-
-            {/* Heartbeat Interval */}
-            <Text style={styles.label}>Heartbeat (seconds)</Text>
-            <TextInput
-              style={styles.input}
-              value={heartbeatInterval}
-              onChangeText={setHeartbeatInterval}
-              keyboardType="numeric"
-              placeholder="15"
-              placeholderTextColor="#475569"
-            />
-
-            {/* Auto-connect */}
-            <View style={styles.switchRow}>
-              <Text style={styles.label}>Auto-connect on start</Text>
-              <Switch value={autoConnect} onValueChange={setAutoConnect} trackColor={{ true: '#3b82f6' }} />
-            </View>
-
-            {/* Log Level */}
-            <Text style={styles.label}>Log Level</Text>
-            <View style={styles.chipRow}>
-              {(['debug', 'info', 'warn', 'error'] as const).map(lv => (
-                <TouchableOpacity
-                  key={lv}
-                  style={[styles.chip, logLevel === lv && styles.chipActive]}
-                  onPress={() => setLogLevel(lv)}
-                >
-                  <Text style={[styles.chipText, logLevel === lv && styles.chipTextActive]}>{lv}</Text>
-                </TouchableOpacity>
-              ))}
-            </View>
-          </>
-        )}
-
-        {tab === 'device' && (
-          <>
-            <Text style={styles.label}>Device Name</Text>
-            <TextInput
-              style={styles.input}
-              value={deviceName}
-              onChangeText={setDeviceName}
-              placeholder="Android Device"
-              placeholderTextColor="#475569"
-            />
-            <View style={styles.infoCard}>
-              <Text style={styles.infoTitle}>Device Info</Text>
-              <Text style={styles.infoText}>Platform: Android</Text>
-              <Text style={styles.infoText}>MCP Server: {gatewayUrl ? 'Configured' : 'Not configured'}</Text>
-              <Text style={styles.infoText}>Capabilities: 36 tools (7 implemented)</Text>
-            </View>
-          </>
-        )}
-
-        {tab === 'connection' && (
-          <>
-            <View style={[styles.connIndicator, styles[`conn_${connStatus}`]]}>
-              <Text style={styles.connText}>
-                {connStatus === 'connected' ? '🟢 Connected' :
-                 connStatus === 'connecting' ? '🟡 Connecting...' :
-                 connStatus === 'error' ? '🔴 Error' : '⚫ Disconnected'}
-              </Text>
-            </View>
-            <TouchableOpacity
-              style={[styles.btn, connStatus === 'connected' ? styles.btnDanger : styles.btnPrimary]}
-              onPress={() => setConnStatus(connStatus === 'disconnected' ? 'connecting' : 'disconnected')}
-            >
-              <Text style={styles.btnText}>
-                {connStatus === 'disconnected' ? 'Connect' : 'Disconnect'}
-              </Text>
+            <TouchableOpacity style={[styles.sendBtn, sending && styles.sendBtnDisabled]} onPress={sendMessage} disabled={sending}>
+              <Text style={styles.sendBtnText}>{sending ? '...' : 'Send'}</Text>
             </TouchableOpacity>
-          </>
-        )}
-      </ScrollView>
-    </View>
+          </View>
+        </View>
+      )}
+
+      {/* ── Settings Tab ── */}
+      {tab === 'settings' && (
+        <ScrollView style={styles.body}>
+          <Text style={styles.label}>Gateway URL</Text>
+          <TextInput style={styles.input} value={gatewayUrl} onChangeText={setGatewayUrl} placeholder="http://localhost:3000" placeholderTextColor="#475569" autoCapitalize="none" keyboardType="url" />
+
+          <Text style={styles.label}>Heartbeat (seconds)</Text>
+          <TextInput style={styles.input} value={heartbeatInterval} onChangeText={setHeartbeatInterval} keyboardType="numeric" placeholder="15" placeholderTextColor="#475569" />
+
+          <View style={styles.switchRow}>
+            <Text style={styles.label}>Auto-connect on start</Text>
+            <Switch value={autoConnect} onValueChange={setAutoConnect} trackColor={{ true: '#3b82f6' }} />
+          </View>
+
+          <Text style={styles.label}>Log Level</Text>
+          <View style={styles.chipRow}>
+            {(['debug', 'info', 'warn', 'error'] as const).map(lv => (
+              <TouchableOpacity key={lv} style={[styles.chip, logLevel === lv && styles.chipActive]} onPress={() => setLogLevel(lv)}>
+                <Text style={[styles.chipText, logLevel === lv && styles.chipTextActive]}>{lv}</Text>
+              </TouchableOpacity>
+            ))}
+          </View>
+        </ScrollView>
+      )}
+
+      {/* ── Device Tab ── */}
+      {tab === 'device' && (
+        <ScrollView style={styles.body}>
+          <Text style={styles.label}>Device Name</Text>
+          <TextInput style={styles.input} value={deviceName} onChangeText={setDeviceName} placeholder="Android Device" placeholderTextColor="#475569" />
+          <View style={styles.infoCard}>
+            <Text style={styles.infoTitle}>Device Info</Text>
+            <Text style={styles.infoText}>Platform: Android</Text>
+            <Text style={styles.infoText}>Gateway: {gatewayUrl}</Text>
+            <Text style={styles.infoText}>Capabilities: exec, file_list, sysinfo...</Text>
+            <Text style={styles.infoText}>MCP Tools: 36 defined, 7 implemented</Text>
+          </View>
+        </ScrollView>
+      )}
+
+      {/* ── Connection Tab ── */}
+      {tab === 'connection' && (
+        <View style={styles.body}>
+          <View style={[styles.connIndicator, styles[`conn_${connStatus}` as keyof typeof styles]]}>
+            <Text style={styles.connText}>
+              {connStatus === 'connected' ? '🟢 Connected' :
+               connStatus === 'connecting' ? '🟡 Connecting...' :
+               connStatus === 'error' ? '🔴 Error' : '⚫ Disconnected'}
+            </Text>
+          </View>
+          <TouchableOpacity
+            style={[styles.btn, connStatus === 'connected' ? styles.btnDanger : styles.btnPrimary]}
+            onPress={toggleConnection}
+          >
+            <Text style={styles.btnText}>{connStatus === 'disconnected' ? 'Connect' : 'Disconnect'}</Text>
+          </TouchableOpacity>
+        </View>
+      )}
+    </KeyboardAvoidingView>
   );
 }
 
+// ── Styles ────────────────────────────────────────────────
+
 const styles = StyleSheet.create({
-  container: { flex: 1, backgroundColor: '#0f172a', paddingTop: 48 },
-  title: { fontSize: 28, fontWeight: '800', color: '#e2e8f0', textAlign: 'center' },
-  subtitle: { fontSize: 12, color: '#64748b', textAlign: 'center', marginBottom: 16 },
-  tabBar: { flexDirection: 'row', marginHorizontal: 16, marginBottom: 16 },
-  tab: {
-    flex: 1, padding: 10, alignItems: 'center',
-    borderBottomWidth: 2, borderBottomColor: '#1e293b',
-  },
+  root: { flex: 1, backgroundColor: '#0f172a' },
+  header: { flexDirection: 'row', justifyContent: 'space-between', alignItems: 'center', paddingHorizontal: 16, paddingTop: 48, paddingBottom: 8 },
+  title: { fontSize: 22, fontWeight: '800', color: '#e2e8f0' },
+  statusDot: { width: 10, height: 10, borderRadius: 5 },
+  dot_connected: { backgroundColor: '#22c55e' },
+  dot_connecting: { backgroundColor: '#eab308' },
+  dot_error: { backgroundColor: '#ef4444' },
+  dot_disconnected: { backgroundColor: '#475569' },
+
+  // Tabs
+  tabBar: { flexDirection: 'row', marginHorizontal: 16, marginBottom: 8 },
+  tab: { flex: 1, padding: 10, alignItems: 'center', borderBottomWidth: 2, borderBottomColor: '#1e293b' },
   tabActive: { borderBottomColor: '#3b82f6' },
-  tabText: { fontSize: 14, color: '#64748b' },
+  tabText: { fontSize: 13, color: '#64748b' },
   tabTextActive: { color: '#3b82f6', fontWeight: '600' },
+
+  // Chat
+  chatContainer: { flex: 1 },
+  chatList: { flex: 1, paddingHorizontal: 12 },
+  bubble: { marginVertical: 4, padding: 10, borderRadius: 10, maxWidth: '85%' },
+  bubbleUser: { alignSelf: 'flex-end', backgroundColor: '#1e40af' },
+  bubbleAI: { alignSelf: 'flex-start', backgroundColor: '#1e293b', borderWidth: 1, borderColor: '#334155' },
+  bubbleRole: { fontSize: 10, color: '#94a3b8', marginBottom: 2 },
+  bubbleText: { fontSize: 14, color: '#e2e8f0' },
+  emptyText: { textAlign: 'center', color: '#475569', marginTop: 40, fontSize: 14 },
+  inputBar: { flexDirection: 'row', padding: 8, paddingBottom: 16, gap: 8 },
+  chatInput: { flex: 1, backgroundColor: '#1e293b', color: '#e2e8f0', borderRadius: 8, paddingHorizontal: 12, paddingVertical: 10, fontSize: 14 },
+  sendBtn: { backgroundColor: '#1e40af', borderRadius: 8, paddingHorizontal: 16, justifyContent: 'center' },
+  sendBtnDisabled: { opacity: 0.5 },
+  sendBtnText: { color: '#fff', fontWeight: '600', fontSize: 14 },
+
+  // Settings
   body: { flex: 1, paddingHorizontal: 16 },
   label: { fontSize: 12, color: '#94a3b8', marginBottom: 4, marginTop: 12 },
-  input: {
-    backgroundColor: '#1e293b', color: '#e2e8f0', borderRadius: 8,
-    padding: 12, fontSize: 14, marginBottom: 4,
-  },
+  input: { backgroundColor: '#1e293b', color: '#e2e8f0', borderRadius: 8, padding: 12, fontSize: 14 },
   switchRow: { flexDirection: 'row', justifyContent: 'space-between', alignItems: 'center', marginTop: 12 },
   chipRow: { flexDirection: 'row', gap: 8, marginTop: 4 },
   chip: { paddingHorizontal: 12, paddingVertical: 6, borderRadius: 16, backgroundColor: '#1e293b' },
@@ -158,6 +237,8 @@ const styles = StyleSheet.create({
   infoCard: { backgroundColor: '#1e293b', borderRadius: 8, padding: 16, marginTop: 16 },
   infoTitle: { fontSize: 14, color: '#38bdf8', marginBottom: 8 },
   infoText: { fontSize: 12, color: '#94a3b8', marginTop: 4 },
+
+  // Connection
   connIndicator: { borderRadius: 8, padding: 16, marginTop: 16, alignItems: 'center' },
   conn_connected: { backgroundColor: '#064e3b' },
   conn_connecting: { backgroundColor: '#78350f' },