diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0e741060..8d370fb7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ The format is based on Keep a Changelog and this project follows Semantic Versio
 ## [Unreleased]
 
 ### Added
+- `general.autoExpandAIGroups` setting: automatically expands all AI response groups when opening a transcript or when new AI responses arrive in a live session. Defaults to off. Stored in the on-disk config so it persists across restarts.
+
+
 - Strict IPC input validation guards for project/session/subagent/search limits.
 - `get-waterfall-data` IPC endpoint implementation.
 - Cross-platform path normalization in renderer path resolvers.
diff --git a/src/main/ipc/configValidation.ts b/src/main/ipc/configValidation.ts
index 469d7c33..b860bd15 100644
--- a/src/main/ipc/configValidation.ts
+++ b/src/main/ipc/configValidation.ts
@@ -203,6 +203,7 @@ function validateGeneralSection(data: unknown): ValidationSuccess<'general'> | V
     'theme',
     'defaultTab',
     'claudeRootPath',
+    'autoExpandAIGroups',
   ];
 
   const result: Partial<GeneralConfig> = {};
@@ -267,6 +268,12 @@ function validateGeneralSection(data: unknown): ValidationSuccess<'general'> | V
           result.claudeRootPath = path.resolve(normalized);
         }
         break;
+      case 'autoExpandAIGroups':
+        if (typeof value !== 'boolean') {
+          return { valid: false, error: `general.${key} must be a boolean` };
+        }
+        result.autoExpandAIGroups = value;
+        break;
       default:
         return { valid: false, error: `Unsupported general key: ${key}` };
     }
diff --git a/src/main/services/infrastructure/ConfigManager.ts b/src/main/services/infrastructure/ConfigManager.ts
index b8999536..7f3ea4a3 100644
--- a/src/main/services/infrastructure/ConfigManager.ts
+++ b/src/main/services/infrastructure/ConfigManager.ts
@@ -181,6 +181,7 @@ export interface GeneralConfig {
   theme: 'dark' | 'light' | 'system';
   defaultTab: 'dashboard' | 'last-session';
   claudeRootPath: string | null;
+  autoExpandAIGroups: boolean;
 }
 
 export interface DisplayConfig {
@@ -248,6 +249,7 @@ const DEFAULT_CONFIG: AppConfig = {
     theme: 'dark',
     defaultTab: 'dashboard',
     claudeRootPath: null,
+    autoExpandAIGroups: false,
   },
   display: {
     showTimestamps: true,
diff --git a/src/renderer/components/settings/hooks/useSettingsConfig.ts b/src/renderer/components/settings/hooks/useSettingsConfig.ts
index 6d3f9c6a..8f4fbdc4 100644
--- a/src/renderer/components/settings/hooks/useSettingsConfig.ts
+++ b/src/renderer/components/settings/hooks/useSettingsConfig.ts
@@ -30,6 +30,7 @@ export interface SafeConfig {
     theme: 'dark' | 'light' | 'system';
     defaultTab: 'dashboard' | 'last-session';
     claudeRootPath: string | null;
+    autoExpandAIGroups: boolean;
   };
   notifications: {
     enabled: boolean;
@@ -154,6 +155,7 @@ export function useSettingsConfig(): UseSettingsConfigReturn {
         theme: displayConfig?.general?.theme ?? 'dark',
         defaultTab: displayConfig?.general?.defaultTab ?? 'dashboard',
         claudeRootPath: displayConfig?.general?.claudeRootPath ?? null,
+        autoExpandAIGroups: displayConfig?.general?.autoExpandAIGroups ?? false,
       },
       notifications: {
         enabled: displayConfig?.notifications?.enabled ?? true,
diff --git a/src/renderer/components/settings/hooks/useSettingsHandlers.ts b/src/renderer/components/settings/hooks/useSettingsHandlers.ts
index 5d6941b0..40a9997f 100644
--- a/src/renderer/components/settings/hooks/useSettingsHandlers.ts
+++ b/src/renderer/components/settings/hooks/useSettingsHandlers.ts
@@ -287,6 +287,7 @@ export function useSettingsHandlers({
           theme: 'dark',
           defaultTab: 'dashboard',
           claudeRootPath: null,
+          autoExpandAIGroups: false,
         },
         display: {
           showTimestamps: true,
diff --git a/src/renderer/components/settings/sections/GeneralSection.tsx b/src/renderer/components/settings/sections/GeneralSection.tsx
index cd28a176..deca9d3f 100644
--- a/src/renderer/components/settings/sections/GeneralSection.tsx
+++ b/src/renderer/components/settings/sections/GeneralSection.tsx
@@ -15,6 +15,7 @@ import { SettingRow, SettingsSectionHeader, SettingsSelect, SettingsToggle } fro
 import type { SafeConfig } from '../hooks/useSettingsConfig';
 import type { ClaudeRootInfo, WslClaudeRootCandidate } from '@shared/types';
 import type { HttpServerStatus } from '@shared/types/api';
+import type { AppConfig } from '@shared/types/notifications';
 
 // Theme options
 const THEME_OPTIONS = [
@@ -26,7 +27,7 @@ const THEME_OPTIONS = [
 interface GeneralSectionProps {
   readonly safeConfig: SafeConfig;
   readonly saving: boolean;
-  readonly onGeneralToggle: (key: 'launchAtLogin' | 'showDockIcon', value: boolean) => void;
+  readonly onGeneralToggle: (key: keyof AppConfig['general'], value: boolean) => void;
   readonly onThemeChange: (value: 'dark' | 'light' | 'system') => void;
 }
 
@@ -286,6 +287,16 @@ export const GeneralSection = ({
           disabled={saving}
         />
       </SettingRow>
+      <SettingRow
+        label="Expand AI responses by default"
+        description="Automatically expand each response turn when opening a transcript or receiving a new message"
+      >
+        <SettingsToggle
+          enabled={safeConfig.general.autoExpandAIGroups ?? false}
+          onChange={(v) => onGeneralToggle('autoExpandAIGroups', v)}
+          disabled={saving}
+        />
+      </SettingRow>
 
       {isElectron && (
         <>
diff --git a/src/renderer/store/slices/sessionDetailSlice.ts b/src/renderer/store/slices/sessionDetailSlice.ts
index 9a158f49..7a1de354 100644
--- a/src/renderer/store/slices/sessionDetailSlice.ts
+++ b/src/renderer/store/slices/sessionDetailSlice.ts
@@ -416,6 +416,15 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
         sessionPhaseInfo: phaseInfo,
       });
 
+      // Auto-expand all AI groups if the setting is enabled
+      if (tabId && conversation?.items && get().appConfig?.general?.autoExpandAIGroups) {
+        for (const item of conversation.items) {
+          if (item.type === 'ai') {
+            get().expandAIGroupForTab(tabId, item.group.id);
+          }
+        }
+      }
+
       // Store per-tab session data
       if (tabId) {
         const prev = get().tabSessionData;
@@ -554,6 +563,14 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
         }
       }
 
+      // Snapshot existing AI group IDs before overwriting state, so the
+      // auto-expand diff below can correctly identify which groups are new.
+      const prevGroupIds = new Set(
+        (latestState.conversation?.items ?? [])
+          .filter((item) => item.type === 'ai')
+          .map((item) => (item as { type: 'ai'; group: { id: string } }).group.id)
+      );
+
       // Update only the data, preserve UI states
       set((state) => ({
         sessionDetail: detail,
@@ -572,6 +589,29 @@ export const createSessionDetailSlice: StateCreator<AppState, [], [], SessionDet
         // so expansion states are preserved
       }));
 
+      // Auto-expand newly arrived AI groups if the setting is enabled.
+      // Uses prevGroupIds snapshotted before set() so the diff is accurate.
+      if (get().appConfig?.general?.autoExpandAIGroups) {
+        const oldGroupIds = prevGroupIds;
+        const newGroupIds = newConversation.items
+          .filter(
+            (item) =>
+              item.type === 'ai' &&
+              !oldGroupIds.has((item as { type: 'ai'; group: { id: string } }).group.id)
+          )
+          .map((item) => (item as { type: 'ai'; group: { id: string } }).group.id);
+
+        if (newGroupIds.length > 0) {
+          for (const tab of latestAllTabs) {
+            if (tab.type === 'session' && tab.sessionId === sessionId) {
+              for (const groupId of newGroupIds) {
+                get().expandAIGroupForTab(tab.id, groupId);
+              }
+            }
+          }
+        }
+      }
+
       // Also update per-tab session data for all tabs viewing this session
       const latestTabSessionData = { ...get().tabSessionData };
       for (const tab of latestAllTabs) {
diff --git a/src/shared/types/notifications.ts b/src/shared/types/notifications.ts
index 245663ab..10dadc50 100644
--- a/src/shared/types/notifications.ts
+++ b/src/shared/types/notifications.ts
@@ -262,6 +262,8 @@ export interface AppConfig {
     defaultTab: 'dashboard' | 'last-session';
     /** Optional custom Claude root folder (auto-detected when null) */
     claudeRootPath: string | null;
+    /** Whether to auto-expand AI response groups when opening a transcript or receiving new messages */
+    autoExpandAIGroups: boolean;
   };
   /** Display and UI settings */
   display: {
diff --git a/test/main/ipc/configValidation.test.ts b/test/main/ipc/configValidation.test.ts
index 0dbd7707..4dcb9714 100644
--- a/test/main/ipc/configValidation.test.ts
+++ b/test/main/ipc/configValidation.test.ts
@@ -20,6 +20,28 @@ describe('configValidation', () => {
     }
   });
 
+  it('accepts general.autoExpandAIGroups boolean toggle', () => {
+    const resultOn = validateConfigUpdatePayload('general', { autoExpandAIGroups: true });
+    expect(resultOn.valid).toBe(true);
+    if (resultOn.valid) {
+      expect(resultOn.data).toEqual({ autoExpandAIGroups: true });
+    }
+
+    const resultOff = validateConfigUpdatePayload('general', { autoExpandAIGroups: false });
+    expect(resultOff.valid).toBe(true);
+    if (resultOff.valid) {
+      expect(resultOff.data).toEqual({ autoExpandAIGroups: false });
+    }
+  });
+
+  it('rejects non-boolean general.autoExpandAIGroups', () => {
+    const result = validateConfigUpdatePayload('general', { autoExpandAIGroups: 'yes' });
+    expect(result.valid).toBe(false);
+    if (!result.valid) {
+      expect(result.error).toContain('boolean');
+    }
+  });
+
   it('accepts absolute general.claudeRootPath updates', () => {
     const result = validateConfigUpdatePayload('general', {
       claudeRootPath: '/Users/test/.claude',