diff --git a/web/src/lib/accessibility.ts b/web/src/lib/accessibility.ts
new file mode 100644
index 0000000..b13bab9
--- /dev/null
+++ b/web/src/lib/accessibility.ts
@@ -0,0 +1,341 @@
+/**
+ * Accessibility utilities for AI Code Battle
+ * Implements plan §15.3: Accessibility Suite
+ */
+
+// Color palettes for player colors
+export interface PlayerPalette {
+  name: string;
+  colors: string[];
+}
+
+export const DEFAULT_PALETTE: PlayerPalette = {
+  name: 'default',
+  colors: [
+    '#2196F3', // Player 1: Blue
+    '#F44336', // Player 2: Red
+    '#4CAF50', // Player 3: Green
+    '#FFEB3B', // Player 4: Yellow
+    '#9C27B0', // Player 5: Purple
+    '#009688', // Player 6: Teal
+  ],
+};
+
+export const COLORBLIND_PALETTE: PlayerPalette = {
+  name: 'tol',
+  colors: [
+    '#0077BB', // Player 1: Blue (Tol)
+    '#EE7733', // Player 2: Orange (Tol)
+    '#009988', // Player 3: Cyan (Tol)
+    '#EE3377', // Player 4: Magenta (Tol)
+    '#BBBBBB', // Player 5: Grey (Tol)
+    '#000000', // Player 6: Black (Tol)
+  ],
+};
+
+export const PALETTES: Record<string, PlayerPalette> = {
+  default: DEFAULT_PALETTE,
+  tol: COLORBLIND_PALETTE,
+};
+
+// Get palette from localStorage or default
+export function getPalette(): PlayerPalette {
+  const stored = localStorage.getItem('color-palette');
+  if (stored && PALETTES[stored]) {
+    return PALETTES[stored];
+  }
+  return DEFAULT_PALETTE;
+}
+
+// Set palette and persist to localStorage
+export function setPalette(paletteName: string): void {
+  if (PALETTES[paletteName]) {
+    localStorage.setItem('color-palette', paletteName);
+    applyPaletteStyles(PALETTES[paletteName]);
+  }
+}
+
+// Apply palette colors as CSS custom properties
+export function applyPaletteStyles(palette: PlayerPalette): void {
+  const root = document.documentElement;
+  palette.colors.forEach((color, i) => {
+    root.style.setProperty(`--player-${i + 1}-color`, color);
+  });
+}
+
+// High contrast mode
+const HIGH_CONTRAST_KEY = 'high-contrast-mode';
+
+export function isHighContrastMode(): boolean {
+  return localStorage.getItem(HIGH_CONTRAST_KEY) === 'true';
+}
+
+export function setHighContrastMode(enabled: boolean): void {
+  localStorage.setItem(HIGH_CONTRAST_KEY, enabled.toString());
+  if (enabled) {
+    document.body.classList.add('high-contrast');
+  } else {
+    document.body.classList.remove('high-contrast');
+  }
+}
+
+export function toggleHighContrastMode(): void {
+  setHighContrastMode(!isHighContrastMode());
+}
+
+// Reduced motion detection
+export function prefersReducedMotion(): boolean {
+  return window.matchMedia('(prefers-reduced-motion: reduce)').matches;
+}
+
+// Keyboard shortcuts
+export interface KeyboardShortcut {
+  key: string;
+  description: string;
+  action: () => void;
+}
+
+export const KEYBOARD_SHORTCUTS: KeyboardShortcut[] = [
+  { key: 'Space', description: 'Play / Pause', action: () => {} },
+  { key: '← / →', description: 'Step back / forward one turn', action: () => {} },
+  { key: 'Shift+← / Shift+→', description: 'Jump 10 turns', action: () => {} },
+  { key: '[ / ]', description: 'Previous / Next critical moment', action: () => {} },
+  { key: '1-5', description: 'Speed preset (1×, 2×, 4×, 8×, 16×)', action: () => {} },
+  { key: 'V', description: 'Cycle view mode (dots → territory → influence)', action: () => {} },
+  { key: 'F', description: 'Cycle fog of war perspective', action: () => {} },
+  { key: 'T', description: 'Toggle debug telemetry panel', action: () => {} },
+  { key: 'E', description: 'Toggle event timeline', action: () => {} },
+  { key: 'C', description: 'Toggle commentary subtitles', action: () => {} },
+  { key: 'H', description: 'Toggle high contrast mode', action: () => toggleHighContrastMode() },
+  { key: '?', description: 'Show keyboard shortcuts overlay', action: () => {} },
+];
+
+// Register keyboard shortcuts with a callback function
+export function registerKeyboardShortcuts(callbacks: Map<string, () => void>): () => void {
+  const handleKeyDown = (e: KeyboardEvent) => {
+    const key = e.key;
+    const shift = e.shiftKey;
+    const ctrl = e.ctrlKey;
+    const meta = e.metaKey;
+
+    // Don't trigger if typing in an input
+    if (e.target instanceof HTMLInputElement || e.target instanceof HTMLTextAreaElement) {
+      return;
+    }
+
+    let shortcutKey = key;
+    if (shift) shortcutKey = 'Shift+' + key;
+    if (ctrl) shortcutKey = 'Ctrl+' + key;
+    if (meta) shortcutKey = 'Meta+' + key;
+
+    const callback = callbacks.get(shortcutKey);
+    if (callback) {
+      e.preventDefault();
+      callback();
+    }
+  };
+
+  document.addEventListener('keydown', handleKeyDown);
+  return () => document.removeEventListener('keydown', handleKeyDown);
+}
+
+// ARIA live region helpers
+export function announceToScreenReader(message: string, priority: 'polite' | 'assertive' = 'polite'): void {
+  const region = document.createElement('div');
+  region.setAttribute('aria-live', priority);
+  region.setAttribute('aria-atomic', 'true');
+  region.className = 'sr-only';
+  region.textContent = message;
+
+  document.body.appendChild(region);
+
+  // Remove after announcement
+  setTimeout(() => {
+    document.body.removeChild(region);
+  }, 1000);
+}
+
+// Create ARIA live region element
+export function createLiveRegion(id: string, priority: 'polite' | 'assertive' = 'polite'): HTMLElement {
+  const region = document.createElement('div');
+  region.id = id;
+  region.setAttribute('aria-live', priority);
+  region.setAttribute('aria-atomic', 'true');
+  region.className = 'sr-only';
+  return region;
+}
+
+// Focus management
+export function setFocus(element: HTMLElement): void {
+  element.focus();
+}
+
+export function makeFocusable(element: HTMLElement): void {
+  if (!element.getAttribute('tabindex')) {
+    element.setAttribute('tabindex', '0');
+  }
+}
+
+export function addFocusIndicator(element: HTMLElement): void {
+  element.style.outline = '2px solid #2196F3';
+  element.style.outlineOffset = '2px';
+}
+
+// Skip-to-content link
+export function createSkipLink(targetId: string, label: string = 'Skip to content'): HTMLElement {
+  const link = document.createElement('a');
+  link.href = `#${targetId}`;
+  link.textContent = label;
+  link.className = 'skip-link';
+  link.setAttribute('aria-label', label);
+
+  // Add styles for skip link
+  const style = document.createElement('style');
+  style.textContent = `
+    .skip-link {
+      position: absolute;
+      top: -40px;
+      left: 0;
+      background: #2196F3;
+      color: white;
+      padding: 8px;
+      text-decoration: none;
+      z-index: 10000;
+      border-radius: 0 0 4px 0;
+    }
+    .skip-link:focus {
+      top: 0;
+    }
+  `;
+  document.head.appendChild(style);
+
+  return link;
+}
+
+// Screen reader transcript generator
+export interface TurnEvent {
+  type: string;
+  player?: number;
+  botName?: string;
+  position?: [number, number];
+  count?: number;
+}
+
+export interface TurnSummary {
+  turn: number;
+  playerMoves: Map<number, number>; // player -> move count
+  combatEvents: TurnEvent[];
+  energyCollected: TurnEvent[];
+  spawns: TurnEvent[];
+  captures: TurnEvent[];
+  winProb: number[];
+}
+
+export function generateTurnSummary(summary: TurnSummary): string {
+  const parts: string[] = [];
+
+  // Player movements
+  const moveDescriptions: string[] = [];
+  summary.playerMoves.forEach((count, player) => {
+    moveDescriptions.push(`Player ${player + 1} moved ${count} bot${count !== 1 ? 's' : ''}`);
+  });
+  if (moveDescriptions.length > 0) {
+    parts.push(moveDescriptions.join('. '));
+  }
+
+  // Combat events
+  if (summary.combatEvents.length > 0) {
+    const combatDesc = summary.combatEvents.map(e => {
+      const loc = e.position ? `at (${e.position[0]},${e.position[1]})` : '';
+      const count = e.count || 1;
+      return `${count} ${e.botName || 'bot'} unit${count !== 1 ? 's' : ''} killed ${loc}`;
+    }).join(', ');
+    parts.push(`Combat: ${combatDesc}`);
+  }
+
+  // Energy collection
+  if (summary.energyCollected.length > 0) {
+    const energyDesc = summary.energyCollected.map(e => {
+      const loc = e.position ? `at (${e.position[0]},${e.position[1]})` : '';
+      return `energy ${loc}`;
+    }).join(', ');
+    parts.push(`Collected ${energyDesc}`);
+  }
+
+  // Spawns
+  if (summary.spawns.length > 0) {
+    const spawnCount = summary.spawns.reduce((sum, e) => sum + (e.count || 1), 0);
+    parts.push(`${spawnCount} bot${spawnCount !== 1 ? 's' : ''} spawned`);
+  }
+
+  // Core captures
+  if (summary.captures.length > 0) {
+    const captureDesc = summary.captures.map(e => {
+      const player = e.player !== undefined ? `Player ${e.player + 1}` : 'A player';
+      return `${player}'s core captured`;
+    }).join(', ');
+    parts.push(captureDesc);
+  }
+
+  // Win probability
+  if (summary.winProb.length >= 2) {
+    const probDesc = summary.winProb.map((p, i) => `Player ${i + 1}: ${Math.round(p * 100)}%`).join(', ');
+    parts.push(`Win probability: ${probDesc}`);
+  }
+
+  return `Turn ${summary.turn}: ${parts.join('. ')}.`;
+}
+
+// Generate full transcript for screen reader
+export function generateTranscript(turns: TurnSummary[]): string[] {
+  return turns.map(generateTurnSummary);
+}
+
+// Initialize accessibility features
+export function initAccessibility(): void {
+  // Apply saved palette
+  const palette = getPalette();
+  applyPaletteStyles(palette);
+
+  // Apply high contrast mode if saved
+  if (isHighContrastMode()) {
+    document.body.classList.add('high-contrast');
+  }
+
+  // Add skip-to-content link
+  const skipLink = createSkipLink('main-content');
+  document.body.insertBefore(skipLink, document.body.firstChild);
+
+  // Add screen reader only styles
+  const srStyle = document.createElement('style');
+  srStyle.textContent = `
+    .sr-only {
+      position: absolute;
+      width: 1px;
+      height: 1px;
+      padding: 0;
+      margin: -1px;
+      overflow: hidden;
+      clip: rect(0, 0, 0, 0);
+      white-space: nowrap;
+      border-width: 0;
+    }
+  `;
+  document.head.appendChild(srStyle);
+}
+
+// Shape per player (redundant encoding for color blindness)
+export const PLAYER_SHAPES = [
+  'circle',      // Player 1
+  'square',      // Player 2
+  'triangle',    // Player 3
+  'diamond',     // Player 4
+  'pentagon',    // Player 5
+  'hexagon',     // Player 6
+] as const;
+
+export type PlayerShape = typeof PLAYER_SHAPES[number];
+
+export function getPlayerShape(playerIndex: number): PlayerShape {
+  return PLAYER_SHAPES[playerIndex % PLAYER_SHAPES.length];
+}