Changed max height

packages/cli/src/ui/components/MainContent.tsx

@@ -48,6 +48,7 @@ export const MainContent = () => {
     pendingHistoryItems,
     mainAreaWidth,
     staticAreaMaxItemHeight,
+    availableTerminalHeight,
     cleanUiDetailsVisible,
   } = uiState;
   const showHeaderDetails = cleanUiDetailsVisible;
@@ -70,9 +71,11 @@ export const MainContent = () => {
           <MemoizedHistoryItemDisplay
             terminalWidth={mainAreaWidth}
             availableTerminalHeight={
-              uiState.constrainHeight || !isExpandable
+              !isExpandable
                 ? staticAreaMaxItemHeight
-                : undefined
+                : uiState.constrainHeight
+                  ? availableTerminalHeight
+                  : undefined
             }
             availableTerminalHeightGemini={MAX_GEMINI_MESSAGE_LINES}
             key={h.id}
@@ -87,6 +90,7 @@ export const MainContent = () => {
       uiState.history,
       mainAreaWidth,
       staticAreaMaxItemHeight,
+      availableTerminalHeight,
       uiState.slashCommands,
       uiState.constrainHeight,
       lastUserPromptIndex,
@@ -110,7 +114,7 @@ export const MainContent = () => {
           <HistoryItemDisplay
             key={i}
             availableTerminalHeight={
-              uiState.constrainHeight ? staticAreaMaxItemHeight : undefined
+              uiState.constrainHeight ? availableTerminalHeight : undefined
             }
             terminalWidth={mainAreaWidth}
             item={{ ...item, id: 0 }}
@@ -126,7 +130,7 @@ export const MainContent = () => {
     [
       pendingHistoryItems,
       uiState.constrainHeight,
-      staticAreaMaxItemHeight,
+      availableTerminalHeight,
       mainAreaWidth,
       showConfirmationQueue,
       confirmingTool,
@@ -161,9 +165,11 @@ export const MainContent = () => {
           <MemoizedHistoryItemDisplay
             terminalWidth={mainAreaWidth}
             availableTerminalHeight={
-              uiState.constrainHeight || !item.isExpandable
+              !item.isExpandable
                 ? staticAreaMaxItemHeight
-                : undefined
+                : uiState.constrainHeight
+                  ? availableTerminalHeight
+                  : undefined
             }
             availableTerminalHeightGemini={MAX_GEMINI_MESSAGE_LINES}
             key={item.item.id}
@@ -185,6 +191,7 @@ export const MainContent = () => {
       pendingItems,
       uiState.constrainHeight,
       staticAreaMaxItemHeight,
+      availableTerminalHeight,
     ],
   );
 

packages/cli/src/ui/components/__snapshots__/MainContent.test.tsx.snap

@@ -6,11 +6,15 @@ AppHeader(full)
 ╭──────────────────────────────────────────────────────────────────────────────────────────────╮
 │ ⊶  Shell Command Running a long command...                                                   │
 │                                                                                              │
-│ Line 10                                                                                      │
+│ Line 6                                                                                       │
-│ Line 11                                                                                      │
+│ Line 7                                                                                       │
-│ Line 12                                                                                      │
+│ Line 8                                                                                       │
-│ Line 13                                                                                      │
+│ Line 9                                                                                     ▄ │
-│ Line 14                                                                                      │
+│ Line 10                                                                                    █ │
+│ Line 11                                                                                    █ │
+│ Line 12                                                                                    █ │
+│ Line 13                                                                                    █ │
+│ Line 14                                                                                    █ │
 │ Line 15                                                                                    █ │
 │ Line 16                                                                                    █ │
 │ Line 17                                                                                    █ │
@@ -28,11 +32,15 @@ AppHeader(full)
 ╭──────────────────────────────────────────────────────────────────────────────────────────────╮
 │ ⊶  Shell Command Running a long command...                                                   │
 │                                                                                              │
-│ Line 10                                                                                      │
+│ Line 6                                                                                       │
-│ Line 11                                                                                      │
+│ Line 7                                                                                       │
-│ Line 12                                                                                      │
+│ Line 8                                                                                       │
-│ Line 13                                                                                      │
+│ Line 9                                                                                     ▄ │
-│ Line 14                                                                                      │
+│ Line 10                                                                                    █ │
+│ Line 11                                                                                    █ │
+│ Line 12                                                                                    █ │
+│ Line 13                                                                                    █ │
+│ Line 14                                                                                    █ │
 │ Line 15                                                                                    █ │
 │ Line 16                                                                                    █ │
 │ Line 17                                                                                    █ │
@@ -49,7 +57,12 @@ exports[`MainContent > MainContent Tool Output Height Logic > 'Normal mode - Con
 ╭──────────────────────────────────────────────────────────────────────────────────────────────╮
 │ ⊶  Shell Command Running a long command...                                                   │
 │                                                                                              │
-│ ... first 11 lines hidden (Ctrl+O to show) ...                                               │
+│ ... first 6 lines hidden (Ctrl+O to show) ...                                                │
+│ Line 7                                                                                       │
+│ Line 8                                                                                       │
+│ Line 9                                                                                       │
+│ Line 10                                                                                      │
+│ Line 11                                                                                      │
 │ Line 12                                                                                      │
 │ Line 13                                                                                      │
 │ Line 14                                                                                      │

packages/cli/src/ui/utils/toolLayoutUtils.test.ts

@@ -0,0 +1,213 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import {
+  calculateToolContentMaxLines,
+  calculateShellMaxLines,
+  TOOL_RESULT_STATIC_HEIGHT,
+  TOOL_RESULT_STANDARD_RESERVED_LINE_COUNT,
+} from './toolLayoutUtils.js';
+import { CoreToolCallStatus } from '@google/gemini-cli-core';
+import {
+  ACTIVE_SHELL_MAX_LINES,
+  COMPLETED_SHELL_MAX_LINES,
+} from '../constants.js';
+
+describe('toolLayoutUtils', () => {
+  describe('calculateToolContentMaxLines', () => {
+    it('returns undefined if availableTerminalHeight is undefined', () => {
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight: undefined,
+        isAlternateBuffer: false,
+      });
+      expect(result).toBeUndefined();
+    });
+
+    it('returns maxLinesLimit if maxLinesLimit applies but availableTerminalHeight is undefined', () => {
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight: undefined,
+        isAlternateBuffer: false,
+        maxLinesLimit: 10,
+      });
+      expect(result).toBe(10);
+    });
+
+    it('caps height to prevent overflow in constrained terminal (Standard mode)', () => {
+      const availableTerminalHeight = 2; // Very small
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight,
+        isAlternateBuffer: false,
+      });
+
+      // Math.max(0, 2 - 1 - 2) = 0
+      expect(result).toBe(0);
+    });
+
+    it('caps height to prevent overflow in constrained terminal (ASB mode)', () => {
+      const availableTerminalHeight = 4; // Very small
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight,
+        isAlternateBuffer: true,
+      });
+
+      // Math.max(0, 4 - 1 - 6) = 0
+      expect(result).toBe(0);
+    });
+
+    it('returns remaining space if sufficient space exists (Standard mode)', () => {
+      const availableTerminalHeight = 20;
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight,
+        isAlternateBuffer: false,
+      });
+
+      // Space remaining is 20 - 1 - 2 = 17
+      expect(result).toBe(17);
+    });
+
+    it('returns remaining space if sufficient space exists (ASB mode)', () => {
+      const availableTerminalHeight = 20;
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight,
+        isAlternateBuffer: true,
+      });
+
+      // Space remaining is 20 - 1 - 6 = 13
+      expect(result).toBe(13);
+    });
+
+    it('returns 0 if availableTerminalHeight is <= TOOL_RESULT_STATIC_HEIGHT + reservedLines', () => {
+      const result = calculateToolContentMaxLines({
+        availableTerminalHeight:
+          TOOL_RESULT_STATIC_HEIGHT + TOOL_RESULT_STANDARD_RESERVED_LINE_COUNT,
+        isAlternateBuffer: false,
+      });
+
+      // Cap at 3 - 1 - 2 = 0
+      expect(result).toBe(0);
+    });
+  });
+
+  describe('calculateShellMaxLines', () => {
+    it('returns undefined when not constrained and is expandable', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: false,
+        isThisShellFocused: false,
+        availableTerminalHeight: 20,
+        constrainHeight: false,
+        isExpandable: true,
+      });
+      expect(result).toBeUndefined();
+    });
+
+    it('returns ACTIVE_SHELL_MAX_LINES for ASB mode when availableTerminalHeight is undefined', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: true,
+        isThisShellFocused: false,
+        availableTerminalHeight: undefined,
+        constrainHeight: true,
+        isExpandable: false,
+      });
+      expect(result).toBe(ACTIVE_SHELL_MAX_LINES);
+    });
+
+    it('returns undefined for Standard mode when availableTerminalHeight is undefined', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: false,
+        isThisShellFocused: false,
+        availableTerminalHeight: undefined,
+        constrainHeight: true,
+        isExpandable: false,
+      });
+      expect(result).toBeUndefined();
+    });
+
+    it('handles small availableTerminalHeight gracefully to prevent overflow in Standard mode', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: false,
+        isThisShellFocused: false,
+        availableTerminalHeight: 2, // Too small to subtract 1 + 2
+        constrainHeight: true,
+        isExpandable: false,
+      });
+
+      // Math.max(0, 2 - 1 - 2) = 0
+      expect(result).toBe(0);
+    });
+
+    it('handles small availableTerminalHeight gracefully to prevent overflow in ASB mode', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: true,
+        isThisShellFocused: false,
+        availableTerminalHeight: 6, // Too small to subtract 1 + 6
+        constrainHeight: true,
+        isExpandable: false,
+      });
+
+      // Math.max(0, 6 - 1 - 6) = 0
+      expect(result).toBe(0);
+    });
+
+    it('handles negative availableTerminalHeight gracefully', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: false,
+        isThisShellFocused: false,
+        availableTerminalHeight: -5,
+        constrainHeight: true,
+        isExpandable: false,
+      });
+
+      expect(result).toBe(0);
+    });
+
+    it('returns maxLinesBasedOnHeight for focused ASB shells', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: true,
+        isThisShellFocused: true,
+        availableTerminalHeight: 30,
+        constrainHeight: false,
+        isExpandable: false,
+      });
+
+      // 30 - 1 (static) - 6 (ASB reserved) = 23
+      expect(result).toBe(23);
+    });
+
+    it('falls back to COMPLETED_SHELL_MAX_LINES for completed shells if space allows', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Success,
+        isAlternateBuffer: false,
+        isThisShellFocused: false,
+        availableTerminalHeight: 100,
+        constrainHeight: true,
+        isExpandable: false,
+      });
+
+      expect(result).toBe(COMPLETED_SHELL_MAX_LINES);
+    });
+
+    it('falls back to ACTIVE_SHELL_MAX_LINES for executing shells if space allows', () => {
+      const result = calculateShellMaxLines({
+        status: CoreToolCallStatus.Executing,
+        isAlternateBuffer: false,
+        isThisShellFocused: false,
+        availableTerminalHeight: 100,
+        constrainHeight: true,
+        isExpandable: false,
+      });
+
+      expect(result).toBe(ACTIVE_SHELL_MAX_LINES);
+    });
+  });
+});

packages/cli/src/ui/utils/toolLayoutUtils.ts

@@ -26,7 +26,7 @@ export const TOOL_RESULT_MIN_LINES_SHOWN = 2;
  * This accounts for:
  * 1. The static height of the tool message (name, status line).
  * 2. Reserved space for hints and padding (different in ASB vs Standard mode).
- * 3. Enforcing a minimum number of lines shown.
+ * 3. Enforcing a physical minimum size based on terminal limits.
  */
 export function calculateToolContentMaxLines(options: {
   availableTerminalHeight: number | undefined;
@@ -41,8 +41,8 @@ export function calculateToolContentMaxLines(options: {
 
   let contentHeight = availableTerminalHeight
     ? Math.max(
+        0,
         availableTerminalHeight - TOOL_RESULT_STATIC_HEIGHT - reservedLines,
-        TOOL_RESULT_MIN_LINES_SHOWN + 1,
       )
     : undefined;
 
@@ -91,7 +91,14 @@ export function calculateShellMaxLines(options: {
     return isAlternateBuffer ? ACTIVE_SHELL_MAX_LINES : undefined;
   }
 
-  const maxLinesBasedOnHeight = Math.max(1, availableTerminalHeight - 2);
+  const reservedLines = isAlternateBuffer
+    ? TOOL_RESULT_ASB_RESERVED_LINE_COUNT
+    : TOOL_RESULT_STANDARD_RESERVED_LINE_COUNT;
+
+  const maxLinesBasedOnHeight = Math.max(
+    0,
+    availableTerminalHeight - TOOL_RESULT_STATIC_HEIGHT - reservedLines,
+  );
 
   // 3. Handle ASB mode focus expansion.
   // We allow a focused shell in ASB mode to take up the full available height,