diff --git a/packages/cli/src/ui/components/messages/ShellToolMessage.test.tsx b/packages/cli/src/ui/components/messages/ShellToolMessage.test.tsx
index 676051501c..09906495dd 100644
--- a/packages/cli/src/ui/components/messages/ShellToolMessage.test.tsx
+++ b/packages/cli/src/ui/components/messages/ShellToolMessage.test.tsx
@@ -356,4 +356,65 @@ describe('<ShellToolMessage />', () => {
       unmount();
     });
   });
+
+  describe('Header Expansion', () => {
+    const LONG_DESCRIPTION = 'very long '.repeat(20);
+
+    it('truncates header by default', async () => {
+      const { lastFrame, waitUntilReady } = await renderWithProviders(
+        <ShellToolMessage
+          {...baseProps}
+          description={LONG_DESCRIPTION}
+          availableTerminalHeight={10}
+        />,
+        { uiActions },
+      );
+
+      await waitUntilReady();
+      const output = lastFrame();
+      // Should be a single line header
+      expect(output.split('\n')[1]).toContain(SHELL_COMMAND_NAME); // name
+      // We check if it's truncated. In our ToolInfo, it's height 1.
+      // The StickyHeader adds some structure, but the ToolInfo Box is inside.
+    });
+
+    it('expands header when availableTerminalHeight is undefined', async () => {
+      const { lastFrame, waitUntilReady } = await renderWithProviders(
+        <ShellToolMessage
+          {...baseProps}
+          description={LONG_DESCRIPTION}
+          availableTerminalHeight={undefined}
+        />,
+        { uiActions },
+      );
+
+      await waitUntilReady();
+      const output = lastFrame();
+      // When expanded, the header (ToolInfo) should wrap and take multiple lines.
+      // Since it's at the top, we check if the first few lines contain parts of the description.
+      const lines = output.split('\n');
+      expect(lines.length).toBeGreaterThan(5);
+    });
+
+    it('expands header when isExpanded is true in context', async () => {
+      const { lastFrame, waitUntilReady } = await renderWithProviders(
+        <ShellToolMessage
+          {...baseProps}
+          description={LONG_DESCRIPTION}
+          availableTerminalHeight={10}
+        />,
+        {
+          uiActions,
+          toolActions: {
+            isExpanded: (id: string) => id === baseProps.callId,
+          },
+        },
+      );
+
+      await waitUntilReady();
+      const output = lastFrame();
+      // Should be expanded due to context
+      expect(output.split('\n').length).toBeGreaterThan(5);
+    });
+  });
 });
diff --git a/packages/cli/src/ui/components/messages/ShellToolMessage.tsx b/packages/cli/src/ui/components/messages/ShellToolMessage.tsx
index f3694f3490..db950a6e51 100644
--- a/packages/cli/src/ui/components/messages/ShellToolMessage.tsx
+++ b/packages/cli/src/ui/components/messages/ShellToolMessage.tsx
@@ -24,6 +24,7 @@ import type { ToolMessageProps } from './ToolMessage.js';
 import { ACTIVE_SHELL_MAX_LINES } from '../../constants.js';
 import { useAlternateBuffer } from '../../hooks/useAlternateBuffer.js';
 import { useUIState } from '../../contexts/UIStateContext.js';
+import { useToolActions } from '../../contexts/ToolActionsContext.js';
 import {
   type Config,
   ShellExecutionService,
@@ -41,6 +42,7 @@ export interface ShellToolMessageProps extends ToolMessageProps {
 }
 
 export const ShellToolMessage: React.FC<ShellToolMessageProps> = ({
+  callId,
   name,
   description,
   resultDisplay,
@@ -57,6 +59,12 @@ export const ShellToolMessage: React.FC<ShellToolMessageProps> = ({
   isExpandable,
   originalRequestName,
 }) => {
+  const { isExpanded: isExpandedInContext } = useToolActions();
+
+  const isExpanded =
+    (isExpandedInContext ? isExpandedInContext(callId) : false) ||
+    availableTerminalHeight === undefined;
+
   const {
     activePtyId: activeShellPtyId,
     embeddedShellFocused,
@@ -169,6 +177,7 @@ export const ShellToolMessage: React.FC<ShellToolMessageProps> = ({
           description={description}
           emphasis={emphasis}
           originalRequestName={originalRequestName}
+          isExpanded={isExpanded}
         />
 
         <FocusHint
diff --git a/packages/cli/src/ui/components/messages/ToolMessage.tsx b/packages/cli/src/ui/components/messages/ToolMessage.tsx
index 5747f7677f..269f00b12d 100644
--- a/packages/cli/src/ui/components/messages/ToolMessage.tsx
+++ b/packages/cli/src/ui/components/messages/ToolMessage.tsx
@@ -24,6 +24,7 @@ import {
 import { type Config, CoreToolCallStatus, Kind } from '@google/gemini-cli-core';
 import { ShellInputPrompt } from '../ShellInputPrompt.js';
 import { SUBAGENT_MAX_LINES } from '../../constants.js';
+import { useToolActions } from '../../contexts/ToolActionsContext.js';
 
 export type { TextEmphasis };
 
@@ -42,6 +43,7 @@ export interface ToolMessageProps extends IndividualToolCallDisplay {
 }
 
 export const ToolMessage: React.FC<ToolMessageProps> = ({
+  callId,
   name,
   description,
   resultDisplay,
@@ -63,6 +65,12 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
   progress,
   progressTotal,
 }) => {
+  const { isExpanded: isExpandedInContext } = useToolActions();
+
+  const isExpanded =
+    (isExpandedInContext ? isExpandedInContext(callId) : false) ||
+    availableTerminalHeight === undefined;
+
   const isThisShellFocused = checkIsShellFocused(
     name,
     status,
@@ -102,6 +110,7 @@ export const ToolMessage: React.FC<ToolMessageProps> = ({
           emphasis={emphasis}
           progressMessage={progressMessage}
           originalRequestName={originalRequestName}
+          isExpanded={isExpanded}
         />
         <FocusHint
           shouldShowFocusHint={shouldShowFocusHint}
diff --git a/packages/cli/src/ui/components/messages/ToolShared.test.tsx b/packages/cli/src/ui/components/messages/ToolShared.test.tsx
index d9fa58e215..1713c3b439 100644
--- a/packages/cli/src/ui/components/messages/ToolShared.test.tsx
+++ b/packages/cli/src/ui/components/messages/ToolShared.test.tsx
@@ -7,7 +7,8 @@
 import { describe, it, expect, vi } from 'vitest';
 import { render } from '../../../test-utils/render.js';
 import { Text } from 'ink';
-import { McpProgressIndicator } from './ToolShared.js';
+import { McpProgressIndicator, ToolInfo } from './ToolShared.js';
+import { CoreToolCallStatus } from '@google/gemini-cli-core';
 
 vi.mock('../GeminiRespondingSpinner.js', () => ({
   GeminiRespondingSpinner: () => <Text>MockSpinner</Text>,
@@ -65,3 +66,37 @@ describe('McpProgressIndicator', () => {
     expect(output).not.toContain('150%');
   });
 });
+
+describe('ToolInfo', () => {
+  const longDescription = 'long '.repeat(50);
+
+  it('truncates description by default', async () => {
+    const { lastFrame } = await render(
+      <ToolInfo
+        name="test-tool"
+        description={longDescription}
+        status={CoreToolCallStatus.Success}
+        emphasis="medium"
+      />,
+    );
+    const output = lastFrame();
+    // In Ink, a single line Box with wrap="truncate" will be truncated.
+    // Since we don't know the exact terminal width in this test, we check if it is short.
+    expect(output.trim().split('\n').length).toBe(1);
+  });
+
+  it('wraps description when isExpanded is true', async () => {
+    const { lastFrame } = await render(
+      <ToolInfo
+        name="test-tool"
+        description={longDescription}
+        status={CoreToolCallStatus.Success}
+        emphasis="medium"
+        isExpanded={true}
+      />,
+    );
+    const output = lastFrame();
+    // When expanded, it should wrap into multiple lines.
+    expect(output.trim().split('\n').length).toBeGreaterThan(1);
+  });
+});
diff --git a/packages/cli/src/ui/components/messages/ToolShared.tsx b/packages/cli/src/ui/components/messages/ToolShared.tsx
index 2aa5ed992a..b246db308b 100644
--- a/packages/cli/src/ui/components/messages/ToolShared.tsx
+++ b/packages/cli/src/ui/components/messages/ToolShared.tsx
@@ -194,6 +194,7 @@ type ToolInfoProps = {
   emphasis: TextEmphasis;
   progressMessage?: string;
   originalRequestName?: string;
+  isExpanded?: boolean;
 };
 
 export const ToolInfo: React.FC<ToolInfoProps> = ({
@@ -203,6 +204,7 @@ export const ToolInfo: React.FC<ToolInfoProps> = ({
   emphasis,
   progressMessage: _progressMessage,
   originalRequestName,
+  isExpanded = false,
 }) => {
   const status = mapCoreStatusToDisplayStatus(coreStatus);
   const nameColor = React.useMemo<string>(() => {
@@ -224,8 +226,16 @@ export const ToolInfo: React.FC<ToolInfoProps> = ({
   const isCompletedAskUser = isCompletedAskUserTool(name, status);
 
   return (
-    <Box overflow="hidden" height={1} flexGrow={1} flexShrink={1}>
-      <Text strikethrough={status === ToolCallStatus.Canceled} wrap="truncate">
+    <Box
+      overflow="hidden"
+      height={isExpanded ? undefined : 1}
+      flexGrow={1}
+      flexShrink={1}
+    >
+      <Text
+        strikethrough={status === ToolCallStatus.Canceled}
+        wrap={isExpanded ? 'wrap' : 'truncate'}
+      >
         <Text color={nameColor} bold>
           {name}
         </Text>
diff --git a/packages/cli/src/ui/components/messages/__snapshots__/ToolGroupMessage.test.tsx.snap b/packages/cli/src/ui/components/messages/__snapshots__/ToolGroupMessage.test.tsx.snap
index f61b9274c9..b0d33feebd 100644
--- a/packages/cli/src/ui/components/messages/__snapshots__/ToolGroupMessage.test.tsx.snap
+++ b/packages/cli/src/ui/components/messages/__snapshots__/ToolGroupMessage.test.tsx.snap
@@ -62,9 +62,9 @@ exports[`<ToolGroupMessage /> > Golden Snapshots > renders empty tool calls arra
 
 exports[`<ToolGroupMessage /> > Golden Snapshots > renders header when scrolled 1`] = `
 "╭──────────────────────────────────────────────────────────────────────────╮
-│ ✓  tool-1 Description 1. This is a long description that will need to b… │                       ▄
+│ ✓  tool-1 Description 1. This is a long description that will need to be │
+│    truncated if the terminal width is small.                             │                       ▄
 │──────────────────────────────────────────────────────────────────────────│                       █
-│ line3                                                                    │                       █
 │ line4                                                                    │                       █
 │ line5                                                                    │                       █
 │                                                                          │                       █
@@ -161,7 +161,10 @@ exports[`<ToolGroupMessage /> > Golden Snapshots > renders with limited terminal
 
 exports[`<ToolGroupMessage /> > Golden Snapshots > renders with narrow terminal width 1`] = `
 "╭──────────────────────────────────╮
-│ ✓  very-long-tool-name-that-mig… │
+│ ✓  very-long-tool-name-that-migh │
+│    t-wrap This is a very long    │
+│    description that might cause  │
+│    wrapping issues               │
 │                                  │
 │ Test result                      │
 ╰──────────────────────────────────╯
diff --git a/packages/cli/src/ui/components/messages/__snapshots__/ToolMessageFocusHint.test.tsx.snap b/packages/cli/src/ui/components/messages/__snapshots__/ToolMessageFocusHint.test.tsx.snap
index 8da15d7fdb..22904f2b29 100644
--- a/packages/cli/src/ui/components/messages/__snapshots__/ToolMessageFocusHint.test.tsx.snap
+++ b/packages/cli/src/ui/components/messages/__snapshots__/ToolMessageFocusHint.test.tsx.snap
@@ -58,7 +58,9 @@ exports[`Focus Hint > 'ToolMessage' > shows focus hint after delay with output >
 
 exports[`Focus Hint > handles long descriptions by shrinking them to show the focus hint > long-description 1`] = `
 "╭──────────────────────────────────────────────────────────────────────────────╮
-│ ⊶  Shell Command AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA… (Tab to focus) │
+│ ⊶  Shell Command                                              (Tab to focus) │
+│    AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA                │
+│    AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA                                │
 │                                                                              │
 "
 `;