diff --git a/src/commands.ts b/src/commands.ts
index 012a6a9bb..508498c27 100644
--- a/src/commands.ts
+++ b/src/commands.ts
@@ -19,6 +19,7 @@ import { context, contextNonInteractive } from './commands/context/index.js'
 import diff from './commands/diff/index.js'
 import doctor from './commands/doctor/index.js'
 import memory from './commands/memory/index.js'
+import mode from './commands/mode/index.js'
 import help from './commands/help/index.js'
 import ide from './commands/ide/index.js'
 import init from './commands/init.js'
@@ -327,6 +328,7 @@ const COMMANDS = memoize((): Command[] => [
   mcp,
   memory,
   mobile,
+  mode,
   model,
   outputStyle,
   remoteEnv,
diff --git a/src/commands/mode/index.ts b/src/commands/mode/index.ts
new file mode 100644
index 000000000..d9b9e7339
--- /dev/null
+++ b/src/commands/mode/index.ts
@@ -0,0 +1,13 @@
+import type { Command } from '../../commands.js'
+
+const mode = {
+  type: 'local-jsx',
+  name: 'mode',
+  description:
+    'Switch interaction mode (default, gentle, sharp, workhorse, token-saver, super-ai)',
+  isEnabled: () => true,
+  argumentHint: '<mode-slug>',
+  load: () => import('./mode.js'),
+} satisfies Command
+
+export default mode
diff --git a/src/commands/mode/mode.tsx b/src/commands/mode/mode.tsx
new file mode 100644
index 000000000..2aad5fde8
--- /dev/null
+++ b/src/commands/mode/mode.tsx
@@ -0,0 +1,79 @@
+import { useMemo } from 'react';
+import { Box, Text } from '@anthropic/ink';
+import { Select } from '../../components/CustomSelect/select.js';
+import type { LocalJSXCommandCall, LocalJSXCommandOnDone } from '../../types/command.js';
+import { getCurrentModeSlug, listModes, setCurrentMode } from '../../modes/store.js';
+
+function ModePicker({ onDone }: { onDone: LocalJSXCommandOnDone }) {
+  const modes = listModes();
+  const currentSlug = getCurrentModeSlug();
+
+  const options = useMemo(
+    () =>
+      modes.map(m => ({
+        label: (
+          <Text>
+            {m.icon} {m.name}{' '}
+            <Text dimColor>
+              ({m.slug}) — {m.description}
+            </Text>
+          </Text>
+        ),
+        value: m.slug,
+      })),
+    [modes],
+  );
+
+  function handleSelect(slug: string) {
+    setCurrentMode(slug);
+    const target = modes.find(m => m.slug === slug);
+    onDone(`${target?.icon} Mode switched to: ${target?.name} (${target?.slug}) — ${target?.description}`, {
+      display: 'system',
+    });
+  }
+
+  function handleCancel() {
+    onDone('Mode selection cancelled.', { display: 'system' });
+  }
+
+  return (
+    <Box flexDirection="column">
+      <Box marginBottom={1} flexDirection="column">
+        <Text color="remember" bold>
+          Select mode
+        </Text>
+        <Text dimColor>Arrow keys to navigate, Enter to select, Esc to cancel.</Text>
+      </Box>
+      <Select
+        defaultValue={currentSlug}
+        options={options}
+        onChange={handleSelect}
+        onCancel={handleCancel}
+        visibleOptionCount={modes.length}
+      />
+    </Box>
+  );
+}
+
+export const call: LocalJSXCommandCall = async (onDone, _context, args) => {
+  const slug = args?.trim().toLowerCase();
+
+  if (slug) {
+    const modes = listModes();
+    const target = modes.find(m => m.slug === slug);
+    if (!target) {
+      const available = modes.map(m => `${m.icon} ${m.slug} — ${m.description}`).join('\n');
+      onDone(`Unknown mode: "${slug}"\n\nAvailable modes:\n${available}`, {
+        display: 'system',
+      });
+      return;
+    }
+    setCurrentMode(slug);
+    onDone(`${target.icon} Mode switched to: ${target.name} (${target.slug}) — ${target.description}`, {
+      display: 'system',
+    });
+    return;
+  }
+
+  return <ModePicker onDone={onDone} />;
+};
diff --git a/src/modes/defaults.ts b/src/modes/defaults.ts
new file mode 100644
index 000000000..79675b163
--- /dev/null
+++ b/src/modes/defaults.ts
@@ -0,0 +1,181 @@
+import type { CCBMode } from './types.js'
+
+const DR_SHARP_SYSTEM_PROMPT = `You are Dr. Sharp, a meticulous code reviewer and diagnostician.
+
+## Core Principles
+
+1. **Diagnose before acting.** Never jump to a fix. Understand the root cause first.
+2. **Minimal effective change.** The smallest diff that fully solves the problem wins.
+3. **Evidence-based.** Every claim must be backed by code, logs, or behavior you can point to.
+4. **No assumptions.** If you're unsure, ask. Never guess about behavior you haven't verified.
+
+## Three-Phase Workflow
+
+### Phase 1: Deep Diagnosis
+- Read the relevant code paths end-to-end
+- Trace the execution flow from input to output
+- Identify the exact point where behavior diverges from expectation
+- State your diagnosis clearly before proceeding
+
+### Phase 2: Action Strategy
+- List 2-3 possible approaches with trade-offs
+- Recommend the minimal effective approach
+- Consider: side effects, edge cases, regression risks
+- Explain WHY this approach over alternatives
+
+### Phase 3: Mirror Self
+- After implementing, re-read the original problem statement
+- Verify your fix addresses the root cause, not just the symptom
+- Check for related issues the same root cause might trigger
+- Run relevant tests to confirm
+
+## Communication Style
+
+- Be direct and specific. No filler.
+- Use code references (file:line) when pointing to issues.
+- When reviewing: "This will break when X because Y. Fix: Z."
+- When diagnosing: "The bug is at X:42. The condition Y evaluates to Z because..."
+- Never apologize for finding problems — that's the job.
+
+## Red Flags to Always Check
+
+- Error handling: are errors caught, logged, and propagated correctly?
+- Edge cases: null, empty, boundary values, concurrent access
+- Security: injection, auth bypass, data leaks
+- Performance: N+1 queries, unnecessary allocations, missing indexes
+- Type safety: any \`as any\` casts, missing null checks, loose types`
+
+export const DEFAULT_MODES: CCBMode[] = [
+  {
+    name: 'Default',
+    slug: 'default',
+    description: 'Balanced mode for everyday development',
+    icon: '⚡',
+    systemPrompt: '',
+    ui: {
+      accentColor: '#D77757',
+      promptPrefix: '',
+    },
+    companionSpecies: 'duck',
+    permissions: {
+      defaultMode: 'default',
+      memoryExtract: true,
+    },
+    responseStyle: {
+      verbosity: 'normal',
+    },
+  },
+  {
+    name: 'Gentle',
+    slug: 'gentle',
+    description: 'Patient explanations, great for learning',
+    icon: '🌸',
+    companionSpecies: 'cat',
+    systemPrompt:
+      'You are in gentle learning mode. Explain concepts clearly with examples. ' +
+      'When correcting mistakes, be encouraging and explain why. ' +
+      'Offer to show alternatives before making changes. ' +
+      'Use analogies to help understand complex concepts.',
+    ui: {
+      accentColor: '#E8A0BF',
+      promptPrefix: 'gentle',
+    },
+    permissions: {
+      defaultMode: 'default',
+      memoryExtract: true,
+    },
+    responseStyle: {
+      verbosity: 'verbose',
+    },
+  },
+  {
+    name: 'Dr. Sharp',
+    slug: 'sharp',
+    description: 'Strict review, focused on code quality',
+    icon: '🔍',
+    companionSpecies: 'owl',
+    systemPrompt: DR_SHARP_SYSTEM_PROMPT,
+    ui: {
+      accentColor: '#5769F7',
+      promptPrefix: 'sharp',
+    },
+    permissions: {
+      defaultMode: 'default',
+      memoryExtract: true,
+    },
+    responseStyle: {
+      verbosity: 'normal',
+    },
+  },
+  {
+    name: 'Workhorse',
+    slug: 'workhorse',
+    description: 'Auto-execute, minimal confirmations',
+    icon: '🐴',
+    companionSpecies: 'capybara',
+    systemPrompt:
+      'You are in workhorse mode. Execute tasks efficiently with minimal back-and-forth. ' +
+      'Make reasonable assumptions and proceed. ' +
+      'Only ask for clarification when truly ambiguous. ' +
+      'Batch related changes together.',
+    ui: {
+      accentColor: '#8B7355',
+      promptPrefix: 'work',
+    },
+    permissions: {
+      defaultMode: 'acceptEdits',
+      memoryExtract: false,
+    },
+    responseStyle: {
+      verbosity: 'minimal',
+    },
+  },
+  {
+    name: 'Token Saver',
+    slug: 'token-saver',
+    description: 'Minimal replies, save tokens',
+    icon: '💰',
+    companionSpecies: 'snail',
+    systemPrompt:
+      'You are in token-saving mode. ' +
+      'Give the shortest correct answer. ' +
+      'Skip explanations unless asked. ' +
+      'Use code blocks directly without preamble. ' +
+      'No pleasantries or filler.',
+    ui: {
+      accentColor: '#4A7C59',
+      promptPrefix: 'save',
+    },
+    permissions: {
+      defaultMode: 'acceptEdits',
+      memoryExtract: false,
+    },
+    responseStyle: {
+      verbosity: 'minimal',
+    },
+  },
+  {
+    name: 'Super AI',
+    slug: 'super-ai',
+    description: 'Deep thinking, comprehensive analysis',
+    icon: '🧠',
+    companionSpecies: 'dragon',
+    systemPrompt:
+      'You are in super AI mode. Think deeply before responding. ' +
+      'Consider multiple approaches and explain trade-offs. ' +
+      'Proactively identify related issues and suggest improvements. ' +
+      'Use structured analysis for complex problems. ' +
+      'Reference relevant best practices and patterns.',
+    ui: {
+      accentColor: '#9B59B6',
+      promptPrefix: 'super',
+    },
+    permissions: {
+      defaultMode: 'default',
+      memoryExtract: true,
+    },
+    responseStyle: {
+      verbosity: 'verbose',
+    },
+  },
+]
diff --git a/src/modes/store.ts b/src/modes/store.ts
new file mode 100644
index 000000000..f7a21117c
--- /dev/null
+++ b/src/modes/store.ts
@@ -0,0 +1,133 @@
+import { existsSync, mkdirSync, readdirSync, readFileSync } from 'fs'
+import { join } from 'path'
+import { useSyncExternalStore } from 'react'
+import { parse as parseYaml } from 'yaml'
+import {
+  getInitialSettings,
+  updateSettingsForSource,
+} from '../utils/settings/settings.js'
+import { getClaudeConfigHomeDir } from '../utils/envUtils.js'
+import { DEFAULT_MODES } from './defaults.js'
+import type { CCBMode } from './types.js'
+
+let currentModeSlug: string | null = null
+let customModes: CCBMode[] | null = null
+const modeListeners = new Set<() => void>()
+
+function loadCustomModes(): CCBMode[] {
+  if (customModes !== null) return customModes
+  customModes = []
+  try {
+    const modesDir = join(getClaudeConfigHomeDir(), 'modes')
+    if (!existsSync(modesDir)) {
+      mkdirSync(modesDir, { recursive: true })
+    }
+    const files = readdirSync(modesDir).filter(
+      f => f.endsWith('.yaml') || f.endsWith('.yml'),
+    )
+    for (const file of files) {
+      try {
+        const raw = readFileSync(join(modesDir, file), 'utf-8')
+        const data = parseYaml(raw) as Record<string, unknown>
+        if (!data.slug || !data.name) continue
+        customModes.push({
+          name: String(data.name),
+          slug: String(data.slug),
+          description: String(data.description || ''),
+          icon: String(data.icon || '🔧'),
+          systemPrompt: String(data.system_prompt || ''),
+          ui: {
+            accentColor: String(
+              (data.ui as Record<string, unknown>)?.accent_color || '#00D4AA',
+            ),
+            promptPrefix: String(
+              (data.ui as Record<string, unknown>)?.prompt_prefix || '',
+            ),
+          },
+          permissions: {
+            defaultMode:
+              ((data.permissions as Record<string, unknown>)
+                ?.default_mode as CCBMode['permissions']['defaultMode']) ||
+              'default',
+            memoryExtract: Boolean(
+              (data.permissions as Record<string, unknown>)?.memory_extract ??
+                true,
+            ),
+          },
+          responseStyle: {
+            verbosity:
+              ((data.response_style as Record<string, unknown>)
+                ?.verbosity as CCBMode['responseStyle']['verbosity']) ||
+              'normal',
+          },
+        })
+      } catch {
+        // skip invalid yaml files
+      }
+    }
+  } catch {
+    // modes directory may not exist
+  }
+  return customModes
+}
+
+function getAllModes(): CCBMode[] {
+  const custom = loadCustomModes()
+  if (custom.length === 0) return DEFAULT_MODES
+  // Custom modes override defaults with same slug
+  const slugs = new Set(custom.map(m => m.slug))
+  return [...custom, ...DEFAULT_MODES.filter(m => !slugs.has(m.slug))]
+}
+
+export function getCurrentModeSlug(): string {
+  if (currentModeSlug === null) {
+    const settings = getInitialSettings() as Record<string, unknown>
+    currentModeSlug = (settings.ccbMode as string) || 'default'
+  }
+  return currentModeSlug
+}
+
+export function getCurrentMode(): CCBMode {
+  const slug = getCurrentModeSlug()
+  const modes = getAllModes()
+  return modes.find(m => m.slug === slug) ?? DEFAULT_MODES[0]
+}
+
+export function setCurrentMode(slug: string): void {
+  const modes = getAllModes()
+  const mode = modes.find(m => m.slug === slug)
+  if (!mode) {
+    throw new Error(
+      `Unknown mode: ${slug}. Available: ${modes.map(m => m.slug).join(', ')}`,
+    )
+  }
+  currentModeSlug = slug
+  updateSettingsForSource('userSettings', { ccbMode: slug } as Record<
+    string,
+    unknown
+  >)
+  for (const listener of modeListeners) listener()
+}
+
+function subscribeMode(listener: () => void): () => void {
+  modeListeners.add(listener)
+  return () => modeListeners.delete(listener)
+}
+
+/** Reactive hook — re-renders the component when the mode changes. */
+export function useCurrentMode(): CCBMode {
+  return useSyncExternalStore(subscribeMode, getCurrentMode)
+}
+
+export function listModes(): CCBMode[] {
+  return getAllModes()
+}
+
+export function cycleMode(): CCBMode {
+  const modes = listModes()
+  const current = getCurrentModeSlug()
+  const idx = modes.findIndex(m => m.slug === current)
+  const next = modes[(idx + 1) % modes.length]
+  setCurrentMode(next.slug)
+  return next
+}
diff --git a/src/modes/types.ts b/src/modes/types.ts
new file mode 100644
index 000000000..ad49a85ae
--- /dev/null
+++ b/src/modes/types.ts
@@ -0,0 +1,21 @@
+import type { PermissionMode } from '../types/permissions.js'
+
+export interface CCBMode {
+  name: string
+  slug: string
+  description: string
+  icon: string
+  systemPrompt: string
+  ui: {
+    accentColor: string
+    promptPrefix: string
+  }
+  companionSpecies?: string
+  permissions: {
+    defaultMode: PermissionMode
+    memoryExtract: boolean
+  }
+  responseStyle: {
+    verbosity: 'minimal' | 'normal' | 'verbose'
+  }
+}