diff --git a/apps/web/components/keyboard-shortcut-tooltip.tsx b/apps/web/components/keyboard-shortcut-tooltip.tsx
new file mode 100644
index 0000000000..5637b4835e
--- /dev/null
+++ b/apps/web/components/keyboard-shortcut-tooltip.tsx
@@ -0,0 +1,96 @@
+/**
+ * Reusable tooltip component for displaying keyboard shortcuts
+ */
+
+import { Tooltip, TooltipContent, TooltipTrigger } from '@kandev/ui/tooltip';
+import { Kbd, KbdGroup } from '@kandev/ui/kbd';
+import type { KeyboardShortcut } from '@/lib/keyboard/constants';
+import { formatShortcut, detectPlatform } from '@/lib/keyboard/utils';
+
+type KeyboardShortcutTooltipProps = {
+  shortcut: KeyboardShortcut;
+  children: React.ReactNode;
+  /** Additional description text to show alongside the shortcut */
+  description?: string;
+  /** Whether to show the tooltip (default: true) */
+  enabled?: boolean;
+};
+
+/**
+ * Tooltip that displays a keyboard shortcut hint
+ * 
+ * @example
+ * ```tsx
+ * <KeyboardShortcutTooltip shortcut={SHORTCUTS.SUBMIT}>
+ *   <Button type="submit">Submit</Button>
+ * </KeyboardShortcutTooltip>
+ * ```
+ */
+export function KeyboardShortcutTooltip({
+  shortcut,
+  children,
+  description,
+  enabled = true,
+}: KeyboardShortcutTooltipProps) {
+  if (!enabled) {
+    return <>{children}</>;
+  }
+
+  const platform = detectPlatform();
+  const formattedShortcut = formatShortcut(shortcut, platform);
+  const parts = formattedShortcut.split('+');
+
+  return (
+    <Tooltip>
+      <TooltipTrigger asChild>{children}</TooltipTrigger>
+      <TooltipContent>
+        <div className="flex items-center gap-2">
+          {description && <span>{description}</span>}
+          <KbdGroup>
+            {parts.map((part, index) => (
+              <Kbd key={index}>{part}</Kbd>
+            ))}
+          </KbdGroup>
+        </div>
+      </TooltipContent>
+    </Tooltip>
+  );
+}
+
+/**
+ * Simple text-only version that just shows the formatted shortcut
+ * Useful for inline display without tooltip
+ * 
+ * @example
+ * ```tsx
+ * <KeyboardShortcutText shortcut={SHORTCUTS.SUBMIT} />
+ * // Renders: Cmd+Enter (on Mac) or Ctrl+Enter (on Windows/Linux)
+ * ```
+ */
+export function KeyboardShortcutText({ shortcut }: { shortcut: KeyboardShortcut }) {
+  const platform = detectPlatform();
+  return <span>{formatShortcut(shortcut, platform)}</span>;
+}
+
+/**
+ * Kbd group version for displaying shortcuts with proper styling
+ * 
+ * @example
+ * ```tsx
+ * <KeyboardShortcutKbd shortcut={SHORTCUTS.SUBMIT} />
+ * ```
+ */
+export function KeyboardShortcutKbd({ shortcut }: { shortcut: KeyboardShortcut }) {
+  const platform = detectPlatform();
+  const formattedShortcut = formatShortcut(shortcut, platform);
+  const parts = formattedShortcut.split('+');
+
+  return (
+    <KbdGroup>
+      {parts.map((part, index) => (
+        <Kbd key={index}>{part}</Kbd>
+      ))}
+    </KbdGroup>
+  );
+}
+
diff --git a/apps/web/components/task-create-dialog.tsx b/apps/web/components/task-create-dialog.tsx
index 2c94bbe4c9..623b31d914 100644
--- a/apps/web/components/task-create-dialog.tsx
+++ b/apps/web/components/task-create-dialog.tsx
@@ -40,6 +40,9 @@ import { useAppStore } from '@/components/state-provider';
 import { useRepositories } from '@/hooks/use-repositories';
 import { useRepositoryBranches } from '@/hooks/use-repository-branches';
 import { useSettingsData } from '@/hooks/use-settings-data';
+import { SHORTCUTS } from '@/lib/keyboard/constants';
+import { useKeyboardShortcutHandler } from '@/hooks/use-keyboard-shortcut';
+import { KeyboardShortcutTooltip } from '@/components/keyboard-shortcut-tooltip';
 
 interface TaskCreateDialogProps {
   open: boolean;
@@ -184,6 +187,11 @@ export function TaskCreateDialog({
     textarea.style.height = `${textarea.scrollHeight}px`;
   }, [description]);
 
+  // Use keyboard shortcut hook for Cmd+Enter / Ctrl+Enter
+  const handleKeyDown = useKeyboardShortcutHandler(SHORTCUTS.SUBMIT, (event) => {
+    handleSubmit(event as unknown as FormEvent);
+  });
+
   const handleSubmit = async (e: FormEvent) => {
     e.preventDefault();
     const trimmedTitle = title.trim();
@@ -283,6 +291,7 @@ export function TaskCreateDialog({
                 placeholder="Write a prompt for the agent..."
                 value={description}
                 onChange={(e) => setDescription(e.target.value)}
+                onKeyDown={handleKeyDown}
                 rows={2}
                 className="min-h-[96px] max-h-[240px] resize-y overflow-auto"
               />
@@ -498,9 +507,11 @@ export function TaskCreateDialog({
                 Cancel
               </Button>
             </DialogClose>
-            <Button type="submit" disabled={!title.trim() || (!isEditMode && !repositoryId)}>
-              {submitLabel}
-            </Button>
+            <KeyboardShortcutTooltip shortcut={SHORTCUTS.SUBMIT}>
+              <Button type="submit" disabled={!title.trim() || (!isEditMode && !repositoryId)}>
+                {submitLabel}
+              </Button>
+            </KeyboardShortcutTooltip>
           </DialogFooter>
         </form>
       </DialogContent>
diff --git a/apps/web/components/task/task-chat-panel.tsx b/apps/web/components/task/task-chat-panel.tsx
index 381b4c33cf..f9c3386dc2 100644
--- a/apps/web/components/task/task-chat-panel.tsx
+++ b/apps/web/components/task/task-chat-panel.tsx
@@ -33,6 +33,9 @@ import { Tooltip, TooltipContent, TooltipTrigger } from '@kandev/ui/tooltip';
 import { cn } from '@/lib/utils';
 import { useAppStore } from '@/components/state-provider';
 import type { Comment } from '@/lib/types/http';
+import { SHORTCUTS } from '@/lib/keyboard/constants';
+import { useKeyboardShortcutHandler } from '@/hooks/use-keyboard-shortcut';
+import { KeyboardShortcutTooltip } from '@/components/keyboard-shortcut-tooltip';
 
 type AgentOption = {
   id: string;
@@ -266,6 +269,11 @@ export function TaskChatPanel({ agents, onSend, isLoading, isAgentWorking, taskD
     }
   };
 
+  // Use keyboard shortcut hook for Cmd+Enter / Ctrl+Enter
+  const handleKeyDown = useKeyboardShortcutHandler(SHORTCUTS.SUBMIT, (event) => {
+    handleSubmit(event as unknown as FormEvent);
+  });
+
   const formatContent = (comment: Comment) => {
     // For content type comments, the content might be streamed chunks
     // For message type, show as-is
@@ -344,6 +352,7 @@ export function TaskChatPanel({ agents, onSend, isLoading, isAgentWorking, taskD
         <Textarea
           value={messageInput}
           onChange={(event) => setMessageInput(event.target.value)}
+          onKeyDown={handleKeyDown}
           placeholder="Write to submit work to the agent..."
           className={cn(
             'min-h-[90px] resize-none',
@@ -416,7 +425,9 @@ export function TaskChatPanel({ agents, onSend, isLoading, isAgentWorking, taskD
               </TooltipTrigger>
               <TooltipContent>Add attachments</TooltipContent>
             </Tooltip>
-            <Button type="submit">Submit</Button>
+            <KeyboardShortcutTooltip shortcut={SHORTCUTS.SUBMIT}>
+              <Button type="submit">Submit</Button>
+            </KeyboardShortcutTooltip>
           </div>
         </div>
       </form>
diff --git a/apps/web/hooks/use-keyboard-shortcut.ts b/apps/web/hooks/use-keyboard-shortcut.ts
new file mode 100644
index 0000000000..8b38d81356
--- /dev/null
+++ b/apps/web/hooks/use-keyboard-shortcut.ts
@@ -0,0 +1,119 @@
+/**
+ * React hook for handling keyboard shortcuts
+ */
+
+import { useEffect, useCallback, useRef } from 'react';
+import type { KeyboardShortcut } from '@/lib/keyboard/constants';
+import { matchesShortcut } from '@/lib/keyboard/utils';
+
+export type KeyboardShortcutOptions = {
+  /** Whether the shortcut is enabled (default: true) */
+  enabled?: boolean;
+  /** Whether to prevent default behavior (default: true) */
+  preventDefault?: boolean;
+  /** Whether to stop event propagation (default: false) */
+  stopPropagation?: boolean;
+  /** Target element (default: window) */
+  target?: HTMLElement | Window | null;
+};
+
+/**
+ * Hook for handling global keyboard shortcuts
+ * 
+ * @example
+ * ```tsx
+ * useKeyboardShortcut(SHORTCUTS.SUBMIT, handleSubmit);
+ * ```
+ */
+export function useKeyboardShortcut(
+  shortcut: KeyboardShortcut,
+  callback: (event: KeyboardEvent) => void,
+  options: KeyboardShortcutOptions = {}
+) {
+  const {
+    enabled = true,
+    preventDefault = true,
+    stopPropagation = false,
+    target = typeof window !== 'undefined' ? window : null,
+  } = options;
+
+  // Use ref to avoid recreating the handler on every render
+  const callbackRef = useRef(callback);
+  callbackRef.current = callback;
+
+  const handleKeyDown = useCallback(
+    (event: KeyboardEvent) => {
+      if (!enabled) return;
+
+      if (matchesShortcut(event, shortcut)) {
+        if (preventDefault) {
+          event.preventDefault();
+        }
+        if (stopPropagation) {
+          event.stopPropagation();
+        }
+        callbackRef.current(event);
+      }
+    },
+    [enabled, preventDefault, stopPropagation, shortcut]
+  );
+
+  useEffect(() => {
+    if (!enabled || !target) return;
+
+    target.addEventListener('keydown', handleKeyDown as EventListener);
+
+    return () => {
+      target.removeEventListener('keydown', handleKeyDown as EventListener);
+    };
+  }, [enabled, target, handleKeyDown]);
+}
+
+/**
+ * Hook for handling keyboard shortcuts on a specific element (e.g., textarea)
+ * Returns a handler to attach to onKeyDown
+ *
+ * @example
+ * ```tsx
+ * const handleKeyDown = useKeyboardShortcutHandler(SHORTCUTS.SUBMIT, handleSubmit);
+ *
+ * return <textarea onKeyDown={handleKeyDown} />;
+ * ```
+ */
+export function useKeyboardShortcutHandler(
+  shortcut: KeyboardShortcut,
+  callback: (event: React.KeyboardEvent) => void,
+  options: Omit<KeyboardShortcutOptions, 'target'> = {}
+) {
+  const {
+    enabled = true,
+    preventDefault = true,
+    stopPropagation = false,
+  } = options;
+
+  // Use ref to avoid recreating the handler on every render
+  const callbackRef = useRef(callback);
+
+  // Update ref in useEffect to avoid updating during render
+  useEffect(() => {
+    callbackRef.current = callback;
+  }, [callback]);
+
+  return useCallback(
+    (event: React.KeyboardEvent) => {
+      if (!enabled) return;
+
+      if (matchesShortcut(event, shortcut)) {
+        if (preventDefault) {
+          event.preventDefault();
+        }
+        if (stopPropagation) {
+          event.stopPropagation();
+        }
+        callbackRef.current(event);
+      }
+    },
+    [enabled, preventDefault, stopPropagation, shortcut]
+  );
+}
+
diff --git a/apps/web/lib/keyboard/constants.test.ts b/apps/web/lib/keyboard/constants.test.ts
new file mode 100644
index 0000000000..9b7cf83c9a
--- /dev/null
+++ b/apps/web/lib/keyboard/constants.test.ts
@@ -0,0 +1,144 @@
+import { describe, expect, it } from 'vitest';
+import { MODIFIER_KEYS, KEYS, SHORTCUTS } from './constants';
+
+describe('MODIFIER_KEYS', () => {
+  it('defines all modifier keys', () => {
+    expect(MODIFIER_KEYS.CTRL).toBe('Control');
+    expect(MODIFIER_KEYS.CMD).toBe('Meta');
+    expect(MODIFIER_KEYS.ALT).toBe('Alt');
+    expect(MODIFIER_KEYS.SHIFT).toBe('Shift');
+  });
+
+  it('has correct type', () => {
+    // TypeScript ensures these are readonly at compile time
+    const keys: typeof MODIFIER_KEYS = MODIFIER_KEYS;
+    expect(keys).toBeDefined();
+  });
+});
+
+describe('KEYS', () => {
+  it('defines special keys', () => {
+    expect(KEYS.ENTER).toBe('Enter');
+    expect(KEYS.ESCAPE).toBe('Escape');
+    expect(KEYS.SPACE).toBe(' ');
+    expect(KEYS.TAB).toBe('Tab');
+    expect(KEYS.BACKSPACE).toBe('Backspace');
+    expect(KEYS.DELETE).toBe('Delete');
+  });
+
+  it('defines arrow keys', () => {
+    expect(KEYS.ARROW_UP).toBe('ArrowUp');
+    expect(KEYS.ARROW_DOWN).toBe('ArrowDown');
+    expect(KEYS.ARROW_LEFT).toBe('ArrowLeft');
+    expect(KEYS.ARROW_RIGHT).toBe('ArrowRight');
+  });
+
+  it('defines letter keys A-Z', () => {
+    expect(KEYS.A).toBe('a');
+    expect(KEYS.B).toBe('b');
+    expect(KEYS.Z).toBe('z');
+  });
+
+  it('defines number keys 0-9', () => {
+    expect(KEYS.ZERO).toBe('0');
+    expect(KEYS.ONE).toBe('1');
+    expect(KEYS.NINE).toBe('9');
+  });
+
+  it('has correct type', () => {
+    // TypeScript ensures these are readonly at compile time
+    const keys: typeof KEYS = KEYS;
+    expect(keys).toBeDefined();
+  });
+});
+
+describe('SHORTCUTS', () => {
+  describe('SUBMIT', () => {
+    it('uses Enter key with ctrlOrCmd modifier', () => {
+      expect(SHORTCUTS.SUBMIT.key).toBe('Enter');
+      expect(SHORTCUTS.SUBMIT.modifiers?.ctrlOrCmd).toBe(true);
+    });
+  });
+
+  describe('SAVE', () => {
+    it('uses S key with ctrlOrCmd modifier', () => {
+      expect(SHORTCUTS.SAVE.key).toBe('s');
+      expect(SHORTCUTS.SAVE.modifiers?.ctrlOrCmd).toBe(true);
+    });
+  });
+
+  describe('CANCEL', () => {
+    it('uses Escape key without modifiers', () => {
+      expect(SHORTCUTS.CANCEL.key).toBe('Escape');
+      expect(SHORTCUTS.CANCEL.modifiers).toBeUndefined();
+    });
+  });
+
+  describe('SEARCH', () => {
+    it('uses K key with ctrlOrCmd modifier', () => {
+      expect(SHORTCUTS.SEARCH.key).toBe('k');
+      expect(SHORTCUTS.SEARCH.modifiers?.ctrlOrCmd).toBe(true);
+    });
+  });
+
+  describe('NEW_TASK', () => {
+    it('uses N key with ctrlOrCmd modifier', () => {
+      expect(SHORTCUTS.NEW_TASK.key).toBe('n');
+      expect(SHORTCUTS.NEW_TASK.modifiers?.ctrlOrCmd).toBe(true);
+    });
+  });
+
+  describe('TOGGLE_SIDEBAR', () => {
+    it('uses B key with ctrlOrCmd modifier', () => {
+      expect(SHORTCUTS.TOGGLE_SIDEBAR.key).toBe('b');
+      expect(SHORTCUTS.TOGGLE_SIDEBAR.modifiers?.ctrlOrCmd).toBe(true);
+    });
+  });
+
+  it('has correct type', () => {
+    // TypeScript ensures these are readonly at compile time
+    const shortcuts: typeof SHORTCUTS = SHORTCUTS;
+    expect(shortcuts).toBeDefined();
+  });
+
+  it('all shortcuts have valid key property', () => {
+    Object.values(SHORTCUTS).forEach((shortcut) => {
+      expect(shortcut).toHaveProperty('key');
+      expect(typeof shortcut.key).toBe('string');
+    });
+  });
+
+  it('all shortcuts with modifiers have valid modifier properties', () => {
+    Object.values(SHORTCUTS).forEach((shortcut) => {
+      if (shortcut.modifiers) {
+        const validModifiers = ['ctrl', 'cmd', 'alt', 'shift', 'ctrlOrCmd'];
+        Object.keys(shortcut.modifiers).forEach((modifier) => {
+          expect(validModifiers).toContain(modifier);
+        });
+      }
+    });
+  });
+});
+
+describe('Type definitions', () => {
+  it('KeyboardShortcut type accepts valid shortcuts', () => {
+    // These should compile without errors
+    const shortcut1: import('./constants').KeyboardShortcut = {
+      key: 'Enter',
+    };
+    expect(shortcut1.key).toBe('Enter');
+
+    const shortcut2: import('./constants').KeyboardShortcut = {
+      key: 's',
+      modifiers: { ctrlOrCmd: true },
+    };
+    expect(shortcut2.modifiers?.ctrlOrCmd).toBe(true);
+
+    const shortcut3: import('./constants').KeyboardShortcut = {
+      key: 'a',
+      modifiers: { ctrl: true, shift: true, alt: true },
+    };
+    expect(shortcut3.modifiers?.ctrl).toBe(true);
+  });
+});
+
diff --git a/apps/web/lib/keyboard/constants.ts b/apps/web/lib/keyboard/constants.ts
new file mode 100644
index 0000000000..4ce96d9b4f
--- /dev/null
+++ b/apps/web/lib/keyboard/constants.ts
@@ -0,0 +1,117 @@
+/**
+ * Keyboard shortcut constants and key definitions
+ */
+
+// Modifier keys
+export const MODIFIER_KEYS = {
+  CTRL: 'Control',
+  CMD: 'Meta',
+  ALT: 'Alt',
+  SHIFT: 'Shift',
+} as const;
+
+// Common keys
+export const KEYS = {
+  ENTER: 'Enter',
+  ESCAPE: 'Escape',
+  SPACE: ' ',
+  TAB: 'Tab',
+  BACKSPACE: 'Backspace',
+  DELETE: 'Delete',
+  ARROW_UP: 'ArrowUp',
+  ARROW_DOWN: 'ArrowDown',
+  ARROW_LEFT: 'ArrowLeft',
+  ARROW_RIGHT: 'ArrowRight',
+  // Letters
+  A: 'a',
+  B: 'b',
+  C: 'c',
+  D: 'd',
+  E: 'e',
+  F: 'f',
+  G: 'g',
+  H: 'h',
+  I: 'i',
+  J: 'j',
+  K: 'k',
+  L: 'l',
+  M: 'm',
+  N: 'n',
+  O: 'o',
+  P: 'p',
+  Q: 'q',
+  R: 'r',
+  S: 's',
+  T: 't',
+  U: 'u',
+  V: 'v',
+  W: 'w',
+  X: 'x',
+  Y: 'y',
+  Z: 'z',
+  // Numbers
+  ZERO: '0',
+  ONE: '1',
+  TWO: '2',
+  THREE: '3',
+  FOUR: '4',
+  FIVE: '5',
+  SIX: '6',
+  SEVEN: '7',
+  EIGHT: '8',
+  NINE: '9',
+} as const;
+
+// Platform types
+export type Platform = 'mac' | 'windows' | 'linux' | 'unknown';
+
+// Modifier key type
+export type ModifierKey = keyof typeof MODIFIER_KEYS;
+
+// Key type
+export type Key = (typeof KEYS)[keyof typeof KEYS];
+
+/**
+ * Keyboard shortcut definition
+ */
+export type KeyboardShortcut = {
+  key: Key;
+  modifiers?: {
+    ctrl?: boolean;
+    cmd?: boolean;
+    alt?: boolean;
+    shift?: boolean;
+    /** Use Cmd on Mac, Ctrl on Windows/Linux */
+    ctrlOrCmd?: boolean;
+  };
+};
+
+/**
+ * Common keyboard shortcuts used across the app
+ */
+export const SHORTCUTS = {
+  SUBMIT: {
+    key: KEYS.ENTER,
+    modifiers: { ctrlOrCmd: true },
+  },
+  SAVE: {
+    key: KEYS.S,
+    modifiers: { ctrlOrCmd: true },
+  },
+  CANCEL: {
+    key: KEYS.ESCAPE,
+  },
+  SEARCH: {
+    key: KEYS.K,
+    modifiers: { ctrlOrCmd: true },
+  },
+  NEW_TASK: {
+    key: KEYS.N,
+    modifiers: { ctrlOrCmd: true },
+  },
+  TOGGLE_SIDEBAR: {
+    key: KEYS.B,
+    modifiers: { ctrlOrCmd: true },
+  },
+} as const;
+
diff --git a/apps/web/lib/keyboard/utils.test.ts b/apps/web/lib/keyboard/utils.test.ts
new file mode 100644
index 0000000000..d994903028
--- /dev/null
+++ b/apps/web/lib/keyboard/utils.test.ts
@@ -0,0 +1,315 @@
+import { describe, expect, it, beforeEach, vi } from 'vitest';
+import { detectPlatform, isMac, formatShortcut, matchesShortcut } from './utils';
+import { KEYS, SHORTCUTS } from './constants';
+import type { KeyboardShortcut } from './constants';
+
+describe('detectPlatform', () => {
+  beforeEach(() => {
+    // Reset navigator mock before each test
+    vi.unstubAllGlobals();
+  });
+
+  it('detects Mac platform from navigator.platform', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'MacIntel',
+      userAgent: 'Mozilla/5.0',
+    });
+    expect(detectPlatform()).toBe('mac');
+  });
+
+  it('detects Mac platform from userAgent', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'unknown',
+      userAgent: 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)',
+    });
+    expect(detectPlatform()).toBe('mac');
+  });
+
+  it('detects Windows platform', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'Win32',
+      userAgent: 'Mozilla/5.0 (Windows NT 10.0)',
+    });
+    expect(detectPlatform()).toBe('windows');
+  });
+
+  it('detects Linux platform', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'Linux x86_64',
+      userAgent: 'Mozilla/5.0 (X11; Linux x86_64)',
+    });
+    expect(detectPlatform()).toBe('linux');
+  });
+
+  it('returns unknown when navigator is undefined', () => {
+    vi.stubGlobal('navigator', undefined);
+    expect(detectPlatform()).toBe('unknown');
+  });
+
+  it('returns unknown for unrecognized platform', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'FreeBSD',
+      userAgent: 'Mozilla/5.0',
+    });
+    expect(detectPlatform()).toBe('unknown');
+  });
+});
+
+describe('isMac', () => {
+  it('returns true on Mac platform', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'MacIntel',
+      userAgent: 'Mozilla/5.0',
+    });
+    expect(isMac()).toBe(true);
+  });
+
+  it('returns false on Windows platform', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'Win32',
+      userAgent: 'Mozilla/5.0',
+    });
+    expect(isMac()).toBe(false);
+  });
+});
+
+describe('formatShortcut', () => {
+  it('formats Cmd+Enter on Mac', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    expect(formatShortcut(shortcut, 'mac')).toBe('Cmd+Enter');
+  });
+
+  it('formats Ctrl+Enter on Windows', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    expect(formatShortcut(shortcut, 'windows')).toBe('Ctrl+Enter');
+  });
+
+  it('formats Ctrl+Enter on Linux', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    expect(formatShortcut(shortcut, 'linux')).toBe('Ctrl+Enter');
+  });
+
+  it('formats Ctrl+S', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrl: true },
+    };
+    expect(formatShortcut(shortcut, 'windows')).toBe('Ctrl+S');
+  });
+
+  it('formats Cmd+S on Mac', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { cmd: true },
+    };
+    expect(formatShortcut(shortcut, 'mac')).toBe('Cmd+S');
+  });
+
+  it('formats Alt as Option on Mac', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.A,
+      modifiers: { alt: true },
+    };
+    expect(formatShortcut(shortcut, 'mac')).toBe('Option+A');
+  });
+
+  it('formats Alt on Windows', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.A,
+      modifiers: { alt: true },
+    };
+    expect(formatShortcut(shortcut, 'windows')).toBe('Alt+A');
+  });
+
+  it('formats Shift+Ctrl+S', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrl: true, shift: true },
+    };
+    expect(formatShortcut(shortcut, 'windows')).toBe('Ctrl+Shift+S');
+  });
+
+  it('formats key without modifiers', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ESCAPE,
+    };
+    expect(formatShortcut(shortcut, 'mac')).toBe('Esc');
+  });
+
+  it('formats special keys correctly', () => {
+    expect(formatShortcut({ key: KEYS.ESCAPE }, 'mac')).toBe('Esc');
+    expect(formatShortcut({ key: KEYS.SPACE }, 'mac')).toBe('Space');
+    expect(formatShortcut({ key: KEYS.TAB }, 'mac')).toBe('Tab');
+    expect(formatShortcut({ key: KEYS.DELETE }, 'mac')).toBe('Del');
+  });
+
+  it('formats arrow keys with symbols', () => {
+    expect(formatShortcut({ key: KEYS.ARROW_UP }, 'mac')).toBe('↑');
+    expect(formatShortcut({ key: KEYS.ARROW_DOWN }, 'mac')).toBe('↓');
+    expect(formatShortcut({ key: KEYS.ARROW_LEFT }, 'mac')).toBe('←');
+    expect(formatShortcut({ key: KEYS.ARROW_RIGHT }, 'mac')).toBe('→');
+  });
+
+  it('uppercases single letter keys', () => {
+    expect(formatShortcut({ key: KEYS.A }, 'mac')).toBe('A');
+    expect(formatShortcut({ key: KEYS.Z }, 'mac')).toBe('Z');
+  });
+
+  it('uses current platform when not specified', () => {
+    vi.stubGlobal('navigator', {
+      platform: 'MacIntel',
+      userAgent: 'Mozilla/5.0',
+    });
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    expect(formatShortcut(shortcut)).toBe('Cmd+Enter');
+  });
+});
+
+describe('matchesShortcut', () => {
+  it('matches exact key without modifiers', () => {
+    const shortcut: KeyboardShortcut = { key: KEYS.ESCAPE };
+    const event = new KeyboardEvent('keydown', { key: 'Escape' });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('does not match different key', () => {
+    const shortcut: KeyboardShortcut = { key: KEYS.ESCAPE };
+    const event = new KeyboardEvent('keydown', { key: 'Enter' });
+    expect(matchesShortcut(event, shortcut)).toBe(false);
+  });
+
+  it('matches ctrlOrCmd with Ctrl key', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 'Enter', ctrlKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('matches ctrlOrCmd with Meta key', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 'Enter', metaKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('does not match ctrlOrCmd without modifier', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.ENTER,
+      modifiers: { ctrlOrCmd: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 'Enter' });
+    expect(matchesShortcut(event, shortcut)).toBe(false);
+  });
+
+  it('matches Ctrl modifier', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrl: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 's', ctrlKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('matches Cmd modifier', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { cmd: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 's', metaKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('matches Alt modifier', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.A,
+      modifiers: { alt: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 'a', altKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('matches Shift modifier', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.A,
+      modifiers: { shift: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 'a', shiftKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('matches multiple modifiers', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrl: true, shift: true },
+    };
+    const event = new KeyboardEvent('keydown', {
+      key: 's',
+      ctrlKey: true,
+      shiftKey: true,
+    });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('does not match when extra modifier is pressed', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrl: true },
+    };
+    const event = new KeyboardEvent('keydown', {
+      key: 's',
+      ctrlKey: true,
+      shiftKey: true,
+    });
+    expect(matchesShortcut(event, shortcut)).toBe(false);
+  });
+
+  it('does not match when required modifier is missing', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrl: true, shift: true },
+    };
+    const event = new KeyboardEvent('keydown', { key: 's', ctrlKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(false);
+  });
+
+  it('matches ctrlOrCmd with additional modifiers', () => {
+    const shortcut: KeyboardShortcut = {
+      key: KEYS.S,
+      modifiers: { ctrlOrCmd: true, shift: true },
+    };
+    const event = new KeyboardEvent('keydown', {
+      key: 's',
+      ctrlKey: true,
+      shiftKey: true,
+    });
+    expect(matchesShortcut(event, shortcut)).toBe(true);
+  });
+
+  it('does not match when no modifiers expected but some pressed', () => {
+    const shortcut: KeyboardShortcut = { key: KEYS.ESCAPE };
+    const event = new KeyboardEvent('keydown', { key: 'Escape', ctrlKey: true });
+    expect(matchesShortcut(event, shortcut)).toBe(false);
+  });
+
+  it('works with predefined SHORTCUTS', () => {
+    const event = new KeyboardEvent('keydown', { key: 'Enter', metaKey: true });
+    expect(matchesShortcut(event, SHORTCUTS.SUBMIT)).toBe(true);
+  });
+});
+
diff --git a/apps/web/lib/keyboard/utils.ts b/apps/web/lib/keyboard/utils.ts
new file mode 100644
index 0000000000..f00c44b33a
--- /dev/null
+++ b/apps/web/lib/keyboard/utils.ts
@@ -0,0 +1,156 @@
+/**
+ * Keyboard shortcut utility functions
+ */
+
+import type { KeyboardShortcut, Platform } from './constants';
+
+/**
+ * Detect the current platform
+ */
+export function detectPlatform(): Platform {
+  if (typeof navigator === 'undefined') {
+    return 'unknown';
+  }
+
+  const platform = navigator.platform.toLowerCase();
+  const userAgent = navigator.userAgent.toLowerCase();
+
+  if (platform.includes('mac') || userAgent.includes('mac')) {
+    return 'mac';
+  }
+
+  if (platform.includes('win') || userAgent.includes('win')) {
+    return 'windows';
+  }
+
+  if (platform.includes('linux') || userAgent.includes('linux')) {
+    return 'linux';
+  }
+
+  return 'unknown';
+}
+
+/**
+ * Check if the current platform is Mac
+ */
+export function isMac(): boolean {
+  return detectPlatform() === 'mac';
+}
+
+/**
+ * Format a keyboard shortcut for display based on platform
+ * @param shortcut - The keyboard shortcut definition
+ * @param platform - Optional platform override (defaults to current platform)
+ * @returns Formatted string like "Cmd+Enter" or "Ctrl+Enter"
+ */
+export function formatShortcut(shortcut: KeyboardShortcut, platform?: Platform): string {
+  const currentPlatform = platform ?? detectPlatform();
+  const parts: string[] = [];
+
+  if (shortcut.modifiers) {
+    // Handle ctrlOrCmd - use Cmd on Mac, Ctrl elsewhere
+    if (shortcut.modifiers.ctrlOrCmd) {
+      parts.push(currentPlatform === 'mac' ? 'Cmd' : 'Ctrl');
+    } else {
+      // Handle individual modifiers
+      if (shortcut.modifiers.ctrl) {
+        parts.push('Ctrl');
+      }
+      if (shortcut.modifiers.cmd && currentPlatform === 'mac') {
+        parts.push('Cmd');
+      }
+      if (shortcut.modifiers.alt) {
+        parts.push(currentPlatform === 'mac' ? 'Option' : 'Alt');
+      }
+      if (shortcut.modifiers.shift) {
+        parts.push('Shift');
+      }
+    }
+  }
+
+  // Format the key
+  const key = formatKey(shortcut.key);
+  parts.push(key);
+
+  return parts.join('+');
+}
+
+/**
+ * Format a key for display
+ */
+function formatKey(key: string): string {
+  // Special keys
+  const specialKeys: Record<string, string> = {
+    Enter: 'Enter',
+    Escape: 'Esc',
+    ' ': 'Space',
+    Tab: 'Tab',
+    Backspace: 'Backspace',
+    Delete: 'Del',
+    ArrowUp: '↑',
+    ArrowDown: '↓',
+    ArrowLeft: '←',
+    ArrowRight: '→',
+  };
+
+  if (key in specialKeys) {
+    return specialKeys[key];
+  }
+
+  // Uppercase single letters
+  if (key.length === 1) {
+    return key.toUpperCase();
+  }
+
+  return key;
+}
+
+/**
+ * Check if a keyboard event matches a shortcut definition
+ * @param event - The keyboard event
+ * @param shortcut - The shortcut definition to match against
+ * @returns true if the event matches the shortcut
+ */
+export function matchesShortcut(
+  event: KeyboardEvent | React.KeyboardEvent,
+  shortcut: KeyboardShortcut
+): boolean {
+  // Check if the key matches
+  if (event.key !== shortcut.key) {
+    return false;
+  }
+
+  // If no modifiers specified, ensure no modifiers are pressed
+  if (!shortcut.modifiers) {
+    return !event.ctrlKey && !event.metaKey && !event.altKey && !event.shiftKey;
+  }
+
+  const { ctrl, cmd, alt, shift, ctrlOrCmd } = shortcut.modifiers;
+
+  // Handle ctrlOrCmd
+  if (ctrlOrCmd) {
+    const hasCorrectModifier = event.metaKey || event.ctrlKey;
+    if (!hasCorrectModifier) return false;
+
+    // Ensure other modifiers match
+    if (alt && !event.altKey) return false;
+    if (!alt && event.altKey) return false;
+    if (shift && !event.shiftKey) return false;
+    if (!shift && event.shiftKey) return false;
+
+    return true;
+  }
+
+  // Check individual modifiers
+  if (ctrl && !event.ctrlKey) return false;
+  if (!ctrl && event.ctrlKey) return false;
+  if (cmd && !event.metaKey) return false;
+  if (!cmd && event.metaKey) return false;
+  if (alt && !event.altKey) return false;
+  if (!alt && event.altKey) return false;
+  if (shift && !event.shiftKey) return false;
+  if (!shift && event.shiftKey) return false;
+
+  return true;
+}
+
diff --git a/apps/web/package.json b/apps/web/package.json
index 4cae4678b2..fb19e4315a 100644
--- a/apps/web/package.json
+++ b/apps/web/package.json
@@ -66,6 +66,7 @@
     "@types/react-dom": "^19",
     "eslint": "^9",
     "eslint-config-next": "16.1.1",
+    "happy-dom": "^20.1.0",
     "tailwindcss": "^4",
     "typescript": "^5",
     "vitest": "^1.6.0"
diff --git a/apps/web/vitest.config.ts b/apps/web/vitest.config.ts
index 4ac6027d57..a9f5456ffd 100644
--- a/apps/web/vitest.config.ts
+++ b/apps/web/vitest.config.ts
@@ -2,6 +2,6 @@ import { defineConfig } from 'vitest/config';
 
 export default defineConfig({
   test: {
-    environment: 'node',
+    environment: 'happy-dom',
   },
 });