refactor(chat): split MessageBubble into avatar, content and code block components

MessageBubble CC 19 -> below 10. The fence and indented code block rules were identical and are now one CodeBlock component; the Markdown style map lives in markdownStyles.ts. Adds characterization tests for the bubble (roles, actions visibility, edited badge, copy feedback).

__tests__/MessageBubble.test.tsx

@@ -0,0 +1,154 @@
+import { act, fireEvent, render, screen } from '@testing-library/react-native';
+import * as Clipboard from 'expo-clipboard';
+import React from 'react';
+import { MessageBubble } from '../components/chat/MessageBubble';
+import { ChatMessage } from '../store/useAppStore';
+
+jest.mock('expo-clipboard', () => ({ setStringAsync: jest.fn(() => Promise.resolve(true)) }));
+
+let actionsProps: any;
+jest.mock('../components/chat/MessageActions', () => ({
+    MessageActions: (props: any) => {
+        actionsProps = props;
+        const { Text } = require('react-native');
+        return <Text>actions</Text>;
+    },
+}));
+
+const message = (overrides: Partial<ChatMessage> = {}): ChatMessage => ({
+    id: '1',
+    role: 'assistant',
+    content: 'hello **world**',
+    timestamp: new Date(2026, 0, 1, 13, 5).getTime(),
+    ...overrides,
+});
+
+beforeEach(() => {
+    actionsProps = undefined;
+    (Clipboard.setStringAsync as jest.Mock).mockClear();
+});
+
+describe('MessageBubble user message', () => {
+    it('shows the plain text and keeps the actions hidden until touched', () => {
+        render(<MessageBubble message={message({ role: 'user', content: 'hi there' })} />);
+        expect(screen.getByText('hi there')).toBeTruthy();
+        expect(screen.queryByText('actions')).toBeNull();
+    });
+
+    it('reveals edit and delete (but not regenerate) after a touch', () => {
+        const onEdit = jest.fn();
+        const onDelete = jest.fn();
+        const onRegenerate = jest.fn();
+        render(
+            <MessageBubble
+                message={message({ role: 'user', content: 'hi' })}
+                onEdit={onEdit}
+                onDelete={onDelete}
+                onRegenerate={onRegenerate}
+                isLastAssistant
+            />,
+        );
+        fireEvent(screen.getByText('hi').parent!.parent!.parent!.parent!, 'touchStart');
+
+        expect(screen.getByText('actions')).toBeTruthy();
+        expect(actionsProps.role).toBe('user');
+        expect(actionsProps.onEdit).toBe(onEdit);
+        expect(actionsProps.onDelete).toBe(onDelete);
+        expect(actionsProps.onRegenerate).toBeUndefined();
+    });
+
+    it('never renders actions for an empty message', () => {
+        render(<MessageBubble message={message({ role: 'user', content: '' })} />);
+        fireEvent(screen.getByText(/\d/).parent!.parent!.parent!, 'touchStart');
+        expect(screen.queryByText('actions')).toBeNull();
+    });
+});
+
+describe('MessageBubble assistant message', () => {
+    it('renders markdown and always shows actions', () => {
+        render(<MessageBubble message={message()} />);
+        expect(screen.getByText('world')).toBeTruthy();
+        expect(screen.getByText('actions')).toBeTruthy();
+    });
+
+    it('offers regenerate only on the last assistant message and never edit', () => {
+        const onEdit = jest.fn();
+        const onRegenerate = jest.fn();
+        const { rerender } = render(<MessageBubble message={message()} onEdit={onEdit} onRegenerate={onRegenerate} />);
+        expect(actionsProps.onRegenerate).toBeUndefined();
+        expect(actionsProps.onEdit).toBeUndefined();
+
+        rerender(<MessageBubble message={message()} onEdit={onEdit} onRegenerate={onRegenerate} isLastAssistant />);
+        expect(actionsProps.onRegenerate).toBe(onRegenerate);
+        expect(actionsProps.onEdit).toBeUndefined();
+    });
+
+    it('flags actions as streaming only for the last assistant message', () => {
+        const { rerender } = render(<MessageBubble message={message()} isStreaming />);
+        expect(actionsProps.isStreaming).toBeFalsy();
+
+        rerender(<MessageBubble message={message()} isStreaming isLastAssistant />);
+        expect(actionsProps.isStreaming).toBe(true);
+    });
+
+    it('renders nothing inside the bubble or actions while an empty answer is streaming', () => {
+        render(<MessageBubble message={message({ content: '' })} isStreaming isLastAssistant />);
+        expect(screen.queryByText('actions')).toBeNull();
+    });
+
+    it('renders an empty answer as markdown when not streaming', () => {
+        render(<MessageBubble message={message({ content: '' })} />);
+        expect(screen.queryByText('actions')).toBeNull();
+    });
+});
+
+describe('MessageBubble metadata', () => {
+    it('shows the time and the edited badge only for edited messages', () => {
+        const { rerender } = render(<MessageBubble message={message({ role: 'user' })} />);
+        expect(screen.queryByText(/edited/)).toBeNull();
+
+        rerender(<MessageBubble message={message({ role: 'user', isEdited: true })} />);
+        expect(screen.getByText(/· edited/)).toBeTruthy();
+    });
+});
+
+describe('MessageBubble code blocks', () => {
+    const fenced = 'text\n\n```ts\nconst a = 1;\n```\n';
+
+    it('shows the language, the code and copies it to the clipboard', async () => {
+        jest.useFakeTimers();
+        try {
+            render(<MessageBubble message={message({ content: fenced })} />);
+            expect(screen.getByText('ts')).toBeTruthy();
+            expect(screen.getByText(/const a = 1;/)).toBeTruthy();
+            expect(screen.getByText('Copy')).toBeTruthy();
+
+            await act(async () => {
+                fireEvent.press(screen.getByText('Copy'));
+            });
+            expect(Clipboard.setStringAsync).toHaveBeenCalledWith('const a = 1;\n');
+            expect(screen.getByText('Copied!')).toBeTruthy();
+
+            act(() => {
+                jest.advanceTimersByTime(2000);
+            });
+            expect(screen.getByText('Copy')).toBeTruthy();
+        } finally {
+            jest.useRealTimers();
+        }
+    });
+
+    it('labels a fence without a language as "code"', () => {
+        render(<MessageBubble message={message({ content: '```\nplain\n```\n' })} />);
+        expect(screen.getByText('code')).toBeTruthy();
+    });
+
+    it('renders indented code blocks with a "code" header and copy button', async () => {
+        render(<MessageBubble message={message({ content: 'intro\n\n    indented()\n' })} />);
+        expect(screen.getByText('code')).toBeTruthy();
+        await act(async () => {
+            fireEvent.press(screen.getByText('Copy'));
+        });
+        expect(Clipboard.setStringAsync).toHaveBeenCalledWith(expect.stringContaining('indented()'));
+    });
+});

components/chat/CodeBlock.tsx

@@ -0,0 +1,73 @@
+import { Check, Copy } from 'lucide-react-native';
+import React from 'react';
+import { ScrollView, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
+
+interface CodeBlockProps {
+    language: string;
+    content: string;
+    copied: boolean;
+    onCopy: (text: string) => void;
+}
+
+export function CodeBlock({ language, content, copied, onCopy }: CodeBlockProps) {
+    const CopyIcon = copied ? Check : Copy;
+
+    return (
+        <View style={styles.codeBlockWrapper}>
+            <View style={styles.codeBlockHeader}>
+                <Text style={styles.codeBlockLanguage}>{language}</Text>
+                <TouchableOpacity onPress={() => onCopy(content)} style={styles.copyButton}>
+                    <CopyIcon size={14} color="#A0A0A0" />
+                    <Text style={styles.copyText}>{copied ? 'Copied!' : 'Copy'}</Text>
+                </TouchableOpacity>
+            </View>
+            <ScrollView horizontal style={styles.codeScrollView} showsHorizontalScrollIndicator={false}>
+                <Text style={styles.codeText}>{content}</Text>
+            </ScrollView>
+        </View>
+    );
+}
+
+const styles = StyleSheet.create({
+    codeBlockWrapper: {
+        backgroundColor: '#1E1E1E',
+        borderRadius: 8,
+        marginVertical: 8,
+        overflow: 'hidden',
+        width: '100%',
+    },
+    codeBlockHeader: {
+        flexDirection: 'row',
+        justifyContent: 'space-between',
+        alignItems: 'center',
+        backgroundColor: '#2D2D2D',
+        paddingHorizontal: 12,
+        paddingVertical: 8,
+        borderBottomWidth: 1,
+        borderBottomColor: '#404040',
+    },
+    codeBlockLanguage: {
+        color: '#A0A0A0',
+        fontSize: 12,
+        fontFamily: 'monospace',
+        textTransform: 'lowercase',
+    },
+    copyButton: {
+        flexDirection: 'row',
+        alignItems: 'center',
+        gap: 4,
+        padding: 4,
+    },
+    copyText: {
+        color: '#A0A0A0',
+        fontSize: 12,
+    },
+    codeScrollView: {
+        padding: 12,
+    },
+    codeText: {
+        color: '#D4D4D4',
+        fontSize: 13,
+        fontFamily: 'monospace',
+    },
+});

components/chat/MessageBubble.tsx

@@ -1,11 +1,10 @@
 import { useThemeColor } from '@/hooks/useThemeColor';
 import { ChatMessage } from '@/store/useAppStore';
-import Markdown from '@ronradtke/react-native-markdown-display';
+import { Bot, User } from 'lucide-react-native';
-import * as Clipboard from 'expo-clipboard';
+import React, { useState } from 'react';
-import { Bot, Check, Copy, User } from 'lucide-react-native';
+import { StyleSheet, Text, useWindowDimensions, View } from 'react-native';
-import React, { useMemo, useState } from 'react';
-import { ScrollView, StyleSheet, Text, TouchableOpacity, useWindowDimensions, View } from 'react-native';
 import { MessageActions } from './MessageActions';
+import { MessageContent } from './MessageContent';
 
 interface MessageBubbleProps {
     message: ChatMessage;
@@ -16,6 +15,58 @@ interface MessageBubbleProps {
     isLastAssistant?: boolean;
 }
 
+function Avatar({ isUser }: { isUser: boolean }) {
+    const colors = useThemeColor();
+    const Icon = isUser ? User : Bot;
+
+    return (
+        <View style={[styles.avatar, { backgroundColor: isUser ? colors.tint : colors.border }]}>
+            <Icon size={16} color={isUser ? colors.backgroundColor : colors.text} />
+        </View>
+    );
+}
+
+function BubbleRow({ message, showingStreaming }: { message: ChatMessage; showingStreaming: boolean }) {
+    const { width } = useWindowDimensions();
+    const colors = useThemeColor();
+    const isUser = message.role === 'user';
+    const maxWidth = width > 768 ? '70%' : '85%';
+
+    return (
+        <View style={[styles.container, isUser ? styles.containerUser : styles.containerAssistant]}>
+            {!isUser && <Avatar isUser={false} />}
+
+            <View style={[
+                styles.bubble,
+                isUser ? styles.bubbleUser : styles.bubbleAssistant,
+                { maxWidth },
+                { backgroundColor: isUser ? colors.messageUserBg : colors.messageAssistantBg },
+                !isUser && { borderWidth: 1, borderColor: colors.border }
+            ]}>
+                <MessageContent message={message} showingStreaming={showingStreaming} />
+            </View>
+
+            {isUser && <Avatar isUser />}
+        </View>
+    );
+}
+
+/** Timestamp + edited badge. */
+function BubbleMeta({ message }: { message: ChatMessage }) {
+    const colors = useThemeColor();
+    const isUser = message.role === 'user';
+
+    return (
+        <View style={[styles.metaRow, isUser ? styles.metaRowUser : styles.metaRowAssistant]}>
+            {!isUser && <View style={{ width: 32 }} />}
+            <Text style={[styles.timestamp, { color: colors.textMuted }]}>
+                {new Date(message.timestamp).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}
+                {message.isEdited ? ' · edited' : ''}
+            </Text>
+        </View>
+    );
+}
+
 export function MessageBubble({
     message,
     onEdit,
@@ -24,217 +75,21 @@ export function MessageBubble({
     isStreaming,
     isLastAssistant,
 }: MessageBubbleProps) {
-    const { width } = useWindowDimensions();
-    const colors = useThemeColor();
-    const isLargeScreen = width > 768;
     const isUser = message.role === 'user';
     const [showActions, setShowActions] = useState(false);
-    const [copiedText, setCopiedText] = useState<string | null>(null);
 
-    const handleCopy = async (text: string) => {
+    const showingStreaming = !!isStreaming && !!isLastAssistant;
-        await Clipboard.setStringAsync(text);
+    const actionsVisible = (!isUser || showActions) && message.content.length > 0;
-        setCopiedText(text);
-        setTimeout(() => setCopiedText(null), 2000);
-    };
-
-    const showingStreaming = isStreaming && isLastAssistant;
-    const shouldShowActions = !isUser || showActions;
-
-    // UseMemo for dynamic colors
-    const markdownStyles = useMemo(() => ({
-        body: {
-            fontSize: 15,
-            lineHeight: 22,
-            color: colors.messageAssistantText,
-        },
-        strong: {
-            fontWeight: '700',
-            color: colors.text,
-        },
-        em: {
-            fontStyle: 'italic',
-        },
-        code_inline: {
-            backgroundColor: colors.backgroundColor,
-            color: colors.text,
-            paddingHorizontal: 5,
-            paddingVertical: 1,
-            borderRadius: 4,
-            fontSize: 13,
-            fontFamily: 'monospace',
-        },
-        fence: {
-            backgroundColor: colors.inputBg,
-            borderColor: colors.border,
-            borderWidth: 1,
-            color: colors.text,
-            padding: 12,
-            borderRadius: 8,
-            fontSize: 13,
-            fontFamily: 'monospace',
-            marginVertical: 8,
-            overflow: 'hidden',
-        },
-        code_block: {
-            backgroundColor: colors.inputBg,
-            color: colors.text,
-            padding: 12,
-            borderRadius: 8,
-            fontSize: 13,
-            fontFamily: 'monospace',
-            marginVertical: 8,
-        },
-        blockquote: {
-            borderLeftWidth: 3,
-            borderLeftColor: colors.border,
-            paddingLeft: 12,
-            marginVertical: 4,
-            color: colors.textMuted,
-        },
-        bullet_list: {
-            marginVertical: 4,
-        },
-        ordered_list: {
-            marginVertical: 4,
-        },
-        list_item: {
-            marginVertical: 2,
-            color: colors.messageAssistantText,
-        },
-        heading1: {
-            fontSize: 22,
-            fontWeight: '700',
-            marginVertical: 8,
-            color: colors.text,
-        },
-        heading2: {
-            fontSize: 19,
-            fontWeight: '700',
-            marginVertical: 6,
-            color: colors.text,
-        },
-        heading3: {
-            fontSize: 17,
-            fontWeight: '600',
-            marginVertical: 4,
-            color: colors.text,
-        },
-        link: {
-            color: '#3B82F6',
-            textDecorationLine: 'underline',
-        },
-        hr: {
-            backgroundColor: colors.border,
-            height: 1,
-            marginVertical: 12,
-        },
-        paragraph: {
-            marginVertical: 2,
-        },
-    } as any), [colors]); // using 'as any' to satisfy internal Markdown types if needed
-
-    const markdownRules = useMemo(() => ({
-        fence: (node: any, children: any, parent: any, parentStyles: any) => {
-            const content = node.content || '';
-            const language = node.sourceInfo || 'code';
-            return (
-                <View key={node.key} style={styles.codeBlockWrapper}>
-                    <View style={styles.codeBlockHeader}>
-                        <Text style={styles.codeBlockLanguage}>{language}</Text>
-                        <TouchableOpacity onPress={() => handleCopy(content)} style={styles.copyButton}>
-                            {copiedText === content ? <Check size={14} color="#A0A0A0" /> : <Copy size={14} color="#A0A0A0" />}
-                            <Text style={styles.copyText}>{copiedText === content ? 'Copied!' : 'Copy'}</Text>
-                        </TouchableOpacity>
-                    </View>
-                    <ScrollView horizontal style={styles.codeScrollView} showsHorizontalScrollIndicator={false}>
-                        <Text style={styles.codeText}>{content}</Text>
-                    </ScrollView>
-                </View>
-            );
-        },
-        code_block: (node: any, children: any, parent: any, parentStyles: any) => {
-            const content = node.content || '';
-            return (
-                <View key={node.key} style={styles.codeBlockWrapper}>
-                    <View style={styles.codeBlockHeader}>
-                        <Text style={styles.codeBlockLanguage}>code</Text>
-                        <TouchableOpacity onPress={() => handleCopy(content)} style={styles.copyButton}>
-                            {copiedText === content ? <Check size={14} color="#A0A0A0" /> : <Copy size={14} color="#A0A0A0" />}
-                            <Text style={styles.copyText}>{copiedText === content ? 'Copied!' : 'Copy'}</Text>
-                        </TouchableOpacity>
-                    </View>
-                    <ScrollView horizontal style={styles.codeScrollView} showsHorizontalScrollIndicator={false}>
-                        <Text style={styles.codeText}>{content}</Text>
-                    </ScrollView>
-                </View>
-            );
-        }
-    }), [copiedText]);
-
-    const renderContent = () => {
-        if (isUser) {
-            return (
-                <Text style={[styles.text, { color: colors.messageUserText }]}>
-                    {message.content}
-                </Text>
-            );
-        }
-
-        if (!message.content && showingStreaming) {
-            return null; // TypingIndicator handled externally
-        }
-
-        return (
-            <Markdown style={markdownStyles} rules={markdownRules}>
-                {message.content}
-            </Markdown>
-        );
-    };
 
     return (
         <View
             onTouchStart={() => isUser && setShowActions(true)}
             style={styles.outerWrap}
         >
-            <View style={[
+            <BubbleRow message={message} showingStreaming={showingStreaming} />
-                styles.container,
+            <BubbleMeta message={message} />
-                isUser ? styles.containerUser : styles.containerAssistant,
-            ]}>
-                {/* Avatar */}
-                {!isUser && (
-                    <View style={[styles.avatarAssistant, { backgroundColor: colors.border }]}>
-                        <Bot size={16} color={colors.text} />
-                    </View>
-                )}
 
-                <View style={[
+            {actionsVisible && (
-                    styles.bubble,
-                    isUser ? styles.bubbleUser : styles.bubbleAssistant,
-                    { maxWidth: isLargeScreen ? '70%' : '85%' },
-                    { backgroundColor: isUser ? colors.messageUserBg : colors.messageAssistantBg },
-                    !isUser && { borderWidth: 1, borderColor: colors.border }
-                ]}>
-                    {renderContent()}
-                </View>
-
-                {isUser && (
-                    <View style={[styles.avatarUser, { backgroundColor: colors.tint }]}>
-                        <User size={16} color={colors.backgroundColor} />
-                    </View>
-                )}
-            </View>
-
-            {/* Timestamp + edited badge */}
-            <View style={[styles.metaRow, isUser ? styles.metaRowUser : styles.metaRowAssistant]}>
-                {!isUser && <View style={{ width: 32 }} />}
-                <Text style={[styles.timestamp, { color: colors.textMuted }]}>
-                    {new Date(message.timestamp).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}
-                    {message.isEdited ? ' · edited' : ''}
-                </Text>
-            </View>
-
-            {/* Action buttons */}
-            {(shouldShowActions || !isUser) && message.content.length > 0 && (
                 <MessageActions
                     role={message.role}
                     content={message.content}
@@ -266,15 +121,7 @@ const styles = StyleSheet.create({
     containerAssistant: {
         justifyContent: 'flex-start',
     },
-    avatarAssistant: {
+    avatar: {
-        width: 32,
-        height: 32,
-        borderRadius: 16,
-        alignItems: 'center',
-        justifyContent: 'center',
-        marginBottom: 2,
-    },
-    avatarUser: {
         width: 32,
         height: 32,
         borderRadius: 16,
@@ -295,10 +142,6 @@ const styles = StyleSheet.create({
     bubbleAssistant: {
         borderBottomLeftRadius: 6,
     },
-    text: {
-        fontSize: 15,
-        lineHeight: 22,
-    },
     metaRow: {
         flexDirection: 'row',
         paddingHorizontal: 16,
@@ -316,45 +159,4 @@ const styles = StyleSheet.create({
         fontSize: 11,
         fontWeight: '500',
     },
-    codeBlockWrapper: {
-        backgroundColor: '#1E1E1E',
-        borderRadius: 8,
-        marginVertical: 8,
-        overflow: 'hidden',
-        width: '100%',
-    },
-    codeBlockHeader: {
-        flexDirection: 'row',
-        justifyContent: 'space-between',
-        alignItems: 'center',
-        backgroundColor: '#2D2D2D',
-        paddingHorizontal: 12,
-        paddingVertical: 8,
-        borderBottomWidth: 1,
-        borderBottomColor: '#404040',
-    },
-    codeBlockLanguage: {
-        color: '#A0A0A0',
-        fontSize: 12,
-        fontFamily: 'monospace',
-        textTransform: 'lowercase',
-    },
-    copyButton: {
-        flexDirection: 'row',
-        alignItems: 'center',
-        gap: 4,
-        padding: 4,
-    },
-    copyText: {
-        color: '#A0A0A0',
-        fontSize: 12,
-    },
-    codeScrollView: {
-        padding: 12,
-    },
-    codeText: {
-        color: '#D4D4D4',
-        fontSize: 13,
-        fontFamily: 'monospace',
-    },
 });

components/chat/MessageContent.tsx

@@ -0,0 +1,73 @@
+import { useThemeColor } from '@/hooks/useThemeColor';
+import { ChatMessage } from '@/store/useAppStore';
+import Markdown from '@ronradtke/react-native-markdown-display';
+import * as Clipboard from 'expo-clipboard';
+import React, { useMemo, useState } from 'react';
+import { StyleSheet, Text } from 'react-native';
+import { CodeBlock } from './CodeBlock';
+import { createMarkdownStyles } from './markdownStyles';
+
+interface MessageContentProps {
+    message: ChatMessage;
+    /** True while this message is the answer currently being streamed. */
+    showingStreaming: boolean;
+}
+
+export function MessageContent({ message, showingStreaming }: MessageContentProps) {
+    const colors = useThemeColor();
+    const [copiedText, setCopiedText] = useState<string | null>(null);
+
+    const handleCopy = async (text: string) => {
+        await Clipboard.setStringAsync(text);
+        setCopiedText(text);
+        setTimeout(() => setCopiedText(null), 2000);
+    };
+
+    const markdownStyles = useMemo(() => createMarkdownStyles(colors), [colors]);
+
+    const markdownRules = useMemo(() => ({
+        fence: (node: any) => (
+            <CodeBlock
+                key={node.key}
+                language={node.sourceInfo || 'code'}
+                content={node.content || ''}
+                copied={copiedText === (node.content || '')}
+                onCopy={handleCopy}
+            />
+        ),
+        code_block: (node: any) => (
+            <CodeBlock
+                key={node.key}
+                language="code"
+                content={node.content || ''}
+                copied={copiedText === (node.content || '')}
+                onCopy={handleCopy}
+            />
+        ),
+    }), [copiedText]);
+
+    if (message.role === 'user') {
+        return (
+            <Text style={[styles.text, { color: colors.messageUserText }]}>
+                {message.content}
+            </Text>
+        );
+    }
+
+    if (!message.content && showingStreaming) {
+        return null; // TypingIndicator handled externally
+    }
+
+    return (
+        <Markdown style={markdownStyles} rules={markdownRules}>
+            {message.content}
+        </Markdown>
+    );
+}
+
+const styles = StyleSheet.create({
+    text: {
+        fontSize: 15,
+        lineHeight: 22,
+    },
+});

components/chat/markdownStyles.ts

@@ -0,0 +1,99 @@
+import { useThemeColor } from '@/hooks/useThemeColor';
+
+type ThemeColors = ReturnType<typeof useThemeColor>;
+
+/** Style map for the Markdown renderer, derived from the active theme colours. */
+export function createMarkdownStyles(colors: ThemeColors) {
+    return {
+        body: {
+            fontSize: 15,
+            lineHeight: 22,
+            color: colors.messageAssistantText,
+        },
+        strong: {
+            fontWeight: '700',
+            color: colors.text,
+        },
+        em: {
+            fontStyle: 'italic',
+        },
+        code_inline: {
+            backgroundColor: colors.backgroundColor,
+            color: colors.text,
+            paddingHorizontal: 5,
+            paddingVertical: 1,
+            borderRadius: 4,
+            fontSize: 13,
+            fontFamily: 'monospace',
+        },
+        fence: {
+            backgroundColor: colors.inputBg,
+            borderColor: colors.border,
+            borderWidth: 1,
+            color: colors.text,
+            padding: 12,
+            borderRadius: 8,
+            fontSize: 13,
+            fontFamily: 'monospace',
+            marginVertical: 8,
+            overflow: 'hidden',
+        },
+        code_block: {
+            backgroundColor: colors.inputBg,
+            color: colors.text,
+            padding: 12,
+            borderRadius: 8,
+            fontSize: 13,
+            fontFamily: 'monospace',
+            marginVertical: 8,
+        },
+        blockquote: {
+            borderLeftWidth: 3,
+            borderLeftColor: colors.border,
+            paddingLeft: 12,
+            marginVertical: 4,
+            color: colors.textMuted,
+        },
+        bullet_list: {
+            marginVertical: 4,
+        },
+        ordered_list: {
+            marginVertical: 4,
+        },
+        list_item: {
+            marginVertical: 2,
+            color: colors.messageAssistantText,
+        },
+        heading1: {
+            fontSize: 22,
+            fontWeight: '700',
+            marginVertical: 8,
+            color: colors.text,
+        },
+        heading2: {
+            fontSize: 19,
+            fontWeight: '700',
+            marginVertical: 6,
+            color: colors.text,
+        },
+        heading3: {
+            fontSize: 17,
+            fontWeight: '600',
+            marginVertical: 4,
+            color: colors.text,
+        },
+        link: {
+            color: '#3B82F6',
+            textDecorationLine: 'underline',
+        },
+        hr: {
+            backgroundColor: colors.border,
+            height: 1,
+            marginVertical: 12,
+        },
+        paragraph: {
+            marginVertical: 2,
+        },
+        // The Markdown renderer's style types do not accept every RN style key literal.
+    } as any;
+}

jest.config.js

@@ -4,6 +4,10 @@ module.exports = {
   moduleNameMapper: {
     '^@/(.*)$': '<rootDir>/$1',
   },
+  // jest-expo's default pattern plus the ESM-only markdown renderer.
+  transformIgnorePatterns: [
+    'node_modules/(?!((jest-)?react-native|@react-native(-community)?)|expo(nent)?|@expo(nent)?/.*|@expo-google-fonts/.*|react-navigation|@react-navigation/.*|@sentry/react-native|native-base|react-native-svg|@ronradtke/.*)',
+  ],
   testMatch: ['<rootDir>/__tests__/**/*.test.{ts,tsx}'],
   testPathIgnorePatterns: ['/node_modules/', '/dist/', '/.agent/'],
 };