diff --git a/src/App.tsx b/src/App.tsx
index 19862960..f79ac35d 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -290,6 +290,7 @@ function App() {
     onSwitchTheme: themeManager.switchTheme,
     onCreateTheme: async () => { await themeManager.createTheme() },
     onOpenVault: vaultSwitcher.handleOpenLocalFolder,
+    onToggleAIChat: dialogs.toggleAIChat,
   })
 
   const { status: updateStatus, actions: updateActions } = useUpdater()
diff --git a/src/components/AiPanel.test.tsx b/src/components/AiPanel.test.tsx
index 4bd241c0..ebc752c0 100644
--- a/src/components/AiPanel.test.tsx
+++ b/src/components/AiPanel.test.tsx
@@ -1,6 +1,7 @@
 import { describe, it, expect, vi } from 'vitest'
 import { render, screen, fireEvent } from '@testing-library/react'
 import { AiPanel } from './AiPanel'
+import type { VaultEntry } from '../types'
 
 // Mock the hooks and utils to isolate component tests
 vi.mock('../hooks/useAiAgent', () => ({
@@ -16,10 +17,37 @@ vi.mock('../utils/ai-chat', () => ({
   nextMessageId: () => `msg-${Date.now()}`,
 }))
 
+const makeEntry = (overrides: Partial<VaultEntry> = {}): VaultEntry => ({
+  path: '/vault/note/test.md',
+  filename: 'test.md',
+  title: 'Test Note',
+  isA: 'Note',
+  aliases: [],
+  belongsTo: [],
+  relatedTo: [],
+  status: null,
+  owner: null,
+  cadence: null,
+  archived: false,
+  trashed: false,
+  trashedAt: null,
+  modifiedAt: 1700000000,
+  createdAt: 1700000000,
+  fileSize: 100,
+  snippet: '',
+  wordCount: 0,
+  relationships: {},
+  icon: null,
+  color: null,
+  order: null,
+  outgoingLinks: [],
+  ...overrides,
+})
+
 describe('AiPanel', () => {
-  it('renders panel with AI Agent header', () => {
+  it('renders panel with AI Chat header', () => {
     render(<AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" />)
-    expect(screen.getByText('AI Agent')).toBeTruthy()
+    expect(screen.getByText('AI Chat')).toBeTruthy()
   })
 
   it('renders data-testid ai-panel', () => {
@@ -38,9 +66,44 @@ describe('AiPanel', () => {
     expect(onClose).toHaveBeenCalled()
   })
 
-  it('renders empty state when no messages', () => {
+  it('renders empty state without context', () => {
     render(<AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" />)
-    expect(screen.getByText('Ask the AI agent to work with your vault')).toBeTruthy()
+    expect(screen.getByText('Open a note, then ask the AI about it')).toBeTruthy()
+  })
+
+  it('renders contextual empty state when active entry is provided', () => {
+    const entry = makeEntry({ title: 'My Note' })
+    render(
+      <AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" activeEntry={entry} entries={[entry]} allContent={{}} />
+    )
+    expect(screen.getByText('Ask about this note and its linked context')).toBeTruthy()
+  })
+
+  it('shows context bar with active entry title', () => {
+    const entry = makeEntry({ title: 'My Note' })
+    render(
+      <AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" activeEntry={entry} entries={[entry]} allContent={{}} />
+    )
+    expect(screen.getByTestId('context-bar')).toBeTruthy()
+    expect(screen.getByText('My Note')).toBeTruthy()
+  })
+
+  it('shows linked count in context bar when entry has outgoing links', () => {
+    const linked = makeEntry({ path: '/vault/linked.md', title: 'Linked Note' })
+    const entry = makeEntry({ title: 'My Note', outgoingLinks: ['Linked Note'] })
+    render(
+      <AiPanel
+        onClose={vi.fn()} vaultPath="/tmp/vault"
+        activeEntry={entry} entries={[entry, linked]}
+        allContent={{}}
+      />
+    )
+    expect(screen.getByText('+ 1 linked')).toBeTruthy()
+  })
+
+  it('does not show context bar when no active entry', () => {
+    render(<AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" />)
+    expect(screen.queryByTestId('context-bar')).toBeNull()
   })
 
   it('renders input field enabled', () => {
@@ -55,4 +118,19 @@ describe('AiPanel', () => {
     const sendBtn = screen.getByTestId('agent-send')
     expect((sendBtn as HTMLButtonElement).disabled).toBe(true)
   })
+
+  it('shows contextual placeholder when active entry exists', () => {
+    const entry = makeEntry({ title: 'My Note' })
+    render(
+      <AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" activeEntry={entry} entries={[entry]} allContent={{}} />
+    )
+    const input = screen.getByTestId('agent-input') as HTMLInputElement
+    expect(input.placeholder).toBe('Ask about this note...')
+  })
+
+  it('shows generic placeholder when no active entry', () => {
+    render(<AiPanel onClose={vi.fn()} vaultPath="/tmp/vault" />)
+    const input = screen.getByTestId('agent-input') as HTMLInputElement
+    expect(input.placeholder).toBe('Ask the AI agent...')
+  })
 })
diff --git a/src/components/AiPanel.tsx b/src/components/AiPanel.tsx
index 4b5b8178..58186311 100644
--- a/src/components/AiPanel.tsx
+++ b/src/components/AiPanel.tsx
@@ -1,7 +1,9 @@
-import { useState, useRef, useEffect } from 'react'
-import { Robot, X, PaperPlaneRight, Plus } from '@phosphor-icons/react'
+import { useState, useRef, useEffect, useMemo } from 'react'
+import { Robot, X, PaperPlaneRight, Plus, Link } from '@phosphor-icons/react'
 import { AiMessage } from './AiMessage'
 import { useAiAgent, type AiAgentMessage } from '../hooks/useAiAgent'
+import { collectLinkedEntries, buildContextualPrompt } from '../utils/ai-context'
+import type { VaultEntry } from '../types'
 
 export type { AiAgentMessage } from '../hooks/useAiAgent'
 
@@ -9,6 +11,9 @@ interface AiPanelProps {
   onClose: () => void
   onOpenNote?: (path: string) => void
   vaultPath: string
+  activeEntry?: VaultEntry | null
+  entries?: VaultEntry[]
+  allContent?: Record<string, string>
 }
 
 function PanelHeader({ onClose, onClear }: { onClose: () => void; onClear: () => void }) {
@@ -19,7 +24,7 @@ function PanelHeader({ onClose, onClear }: { onClose: () => void; onClear: () =>
     >
       <Robot size={16} className="shrink-0 text-muted-foreground" />
       <span className="flex-1 text-muted-foreground" style={{ fontSize: 13, fontWeight: 600 }}>
-        AI Agent
+        AI Chat
       </span>
       <button
         className="shrink-0 border-none bg-transparent p-1 text-muted-foreground cursor-pointer hover:text-foreground transition-colors"
@@ -39,7 +44,23 @@ function PanelHeader({ onClose, onClear }: { onClose: () => void; onClear: () =>
   )
 }
 
-function EmptyState() {
+function ContextBar({ activeEntry, linkedCount }: { activeEntry: VaultEntry; linkedCount: number }) {
+  return (
+    <div
+      className="flex shrink-0 items-center border-b border-border text-muted-foreground"
+      style={{ padding: '6px 12px', gap: 6, fontSize: 11 }}
+      data-testid="context-bar"
+    >
+      <Link size={12} className="shrink-0" />
+      <span className="truncate" style={{ fontWeight: 500 }}>{activeEntry.title}</span>
+      {linkedCount > 0 && (
+        <span style={{ opacity: 0.6 }}>+ {linkedCount} linked</span>
+      )}
+    </div>
+  )
+}
+
+function EmptyState({ hasContext }: { hasContext: boolean }) {
   return (
     <div
       className="flex flex-col items-center justify-center text-center text-muted-foreground"
@@ -47,17 +68,23 @@ function EmptyState() {
     >
       <Robot size={24} style={{ marginBottom: 8, opacity: 0.5 }} />
       <p style={{ fontSize: 13, margin: '0 0 4px' }}>
-        Ask the AI agent to work with your vault
+        {hasContext
+          ? 'Ask about this note and its linked context'
+          : 'Open a note, then ask the AI about it'
+        }
       </p>
       <p style={{ fontSize: 11, margin: 0, opacity: 0.6 }}>
-        Creates notes, searches, edits frontmatter, and more
+        {hasContext
+          ? 'Summarize, find connections, expand ideas'
+          : 'The AI will use the active note as context'
+        }
       </p>
     </div>
   )
 }
 
-function MessageHistory({ messages, isActive, onOpenNote }: {
-  messages: AiAgentMessage[]; isActive: boolean; onOpenNote?: (path: string) => void
+function MessageHistory({ messages, isActive, onOpenNote, hasContext }: {
+  messages: AiAgentMessage[]; isActive: boolean; onOpenNote?: (path: string) => void; hasContext: boolean
 }) {
   const endRef = useRef<HTMLDivElement>(null)
 
@@ -67,7 +94,7 @@ function MessageHistory({ messages, isActive, onOpenNote }: {
 
   return (
     <div className="flex-1 overflow-y-auto" style={{ padding: 12 }}>
-      {messages.length === 0 && !isActive && <EmptyState />}
+      {messages.length === 0 && !isActive && <EmptyState hasContext={hasContext} />}
       {messages.map((msg, i) => (
         <AiMessage key={msg.id ?? i} {...msg} onOpenNote={onOpenNote} />
       ))}
@@ -76,10 +103,10 @@ function MessageHistory({ messages, isActive, onOpenNote }: {
   )
 }
 
-function InputBar({ input, onInputChange, onSend, onKeyDown, isActive }: {
+function InputBar({ input, onInputChange, onSend, onKeyDown, isActive, hasContext }: {
   input: string; onInputChange: (v: string) => void
   onSend: () => void; onKeyDown: (e: React.KeyboardEvent) => void
-  isActive: boolean
+  isActive: boolean; hasContext: boolean
 }) {
   const sendDisabled = isActive || !input.trim()
   return (
@@ -97,7 +124,7 @@ function InputBar({ input, onInputChange, onSend, onKeyDown, isActive }: {
             fontSize: 13, borderRadius: 8, padding: '8px 10px',
             outline: 'none', fontFamily: 'inherit',
           }}
-          placeholder="Ask the AI agent..."
+          placeholder={hasContext ? 'Ask about this note...' : 'Ask the AI agent...'}
           disabled={isActive}
           data-testid="agent-input"
         />
@@ -121,9 +148,21 @@ function InputBar({ input, onInputChange, onSend, onKeyDown, isActive }: {
   )
 }
 
-export function AiPanel({ onClose, onOpenNote, vaultPath }: AiPanelProps) {
+export function AiPanel({ onClose, onOpenNote, vaultPath, activeEntry, entries, allContent }: AiPanelProps) {
   const [input, setInput] = useState('')
-  const agent = useAiAgent(vaultPath)
+
+  const linkedEntries = useMemo(() => {
+    if (!activeEntry || !entries) return []
+    return collectLinkedEntries(activeEntry, entries)
+  }, [activeEntry, entries])
+
+  const contextPrompt = useMemo(() => {
+    if (!activeEntry || !allContent) return undefined
+    return buildContextualPrompt(activeEntry, linkedEntries, allContent)
+  }, [activeEntry, linkedEntries, allContent])
+
+  const agent = useAiAgent(vaultPath, contextPrompt)
+  const hasContext = !!activeEntry
 
   const isActive = agent.status === 'thinking' || agent.status === 'tool-executing'
 
@@ -146,10 +185,14 @@ export function AiPanel({ onClose, onOpenNote, vaultPath }: AiPanelProps) {
       data-testid="ai-panel"
     >
       <PanelHeader onClose={onClose} onClear={agent.clearConversation} />
+      {activeEntry && (
+        <ContextBar activeEntry={activeEntry} linkedCount={linkedEntries.length} />
+      )}
       <MessageHistory
         messages={agent.messages}
         isActive={isActive}
         onOpenNote={onOpenNote}
+        hasContext={hasContext}
       />
       <InputBar
         input={input}
@@ -157,6 +200,7 @@ export function AiPanel({ onClose, onOpenNote, vaultPath }: AiPanelProps) {
         onSend={handleSend}
         onKeyDown={handleKeyDown}
         isActive={isActive}
+        hasContext={hasContext}
       />
     </aside>
   )
diff --git a/src/components/EditorRightPanel.tsx b/src/components/EditorRightPanel.tsx
index acc728d5..e57206f2 100644
--- a/src/components/EditorRightPanel.tsx
+++ b/src/components/EditorRightPanel.tsx
@@ -38,6 +38,9 @@ export function EditorRightPanel({
           onClose={() => onToggleAIChat?.()}
           onOpenNote={onOpenNote}
           vaultPath={vaultPath}
+          activeEntry={inspectorEntry}
+          entries={entries}
+          allContent={allContent}
         />
       </div>
     )
diff --git a/src/hooks/useAiAgent.ts b/src/hooks/useAiAgent.ts
index ada608f0..b63ec5c0 100644
--- a/src/hooks/useAiAgent.ts
+++ b/src/hooks/useAiAgent.ts
@@ -4,7 +4,7 @@
  *
  * States: idle -> thinking -> tool-executing -> done/error
  */
-import { useState, useCallback, useRef } from 'react'
+import { useState, useCallback, useRef, useEffect } from 'react'
 import type { AiAction } from '../components/AiMessage'
 import { streamClaudeAgent, buildAgentSystemPrompt } from '../utils/ai-agent'
 import { nextMessageId } from '../utils/ai-chat'
@@ -20,10 +20,14 @@ export interface AiAgentMessage {
   id?: string
 }
 
-export function useAiAgent(vaultPath: string) {
+export function useAiAgent(vaultPath: string, contextPrompt?: string) {
   const [messages, setMessages] = useState<AiAgentMessage[]>([])
   const [status, setStatus] = useState<AgentStatus>('idle')
   const abortRef = useRef({ aborted: false })
+  const contextRef = useRef(contextPrompt)
+  useEffect(() => {
+    contextRef.current = contextPrompt
+  }, [contextPrompt])
 
   const sendMessage = useCallback(async (text: string) => {
     if (!text.trim() || status === 'thinking' || status === 'tool-executing') return
@@ -49,7 +53,11 @@ export function useAiAgent(vaultPath: string) {
       setMessages(prev => prev.map(m => m.id === messageId ? fn(m) : m))
     }
 
-    await streamClaudeAgent(text.trim(), buildAgentSystemPrompt(), vaultPath, {
+    // When a contextual prompt is provided (from buildContextualPrompt),
+    // use it directly — it already includes the system preamble.
+    const systemPrompt = contextRef.current ?? buildAgentSystemPrompt()
+
+    await streamClaudeAgent(text.trim(), systemPrompt, vaultPath, {
       onText: (text) => {
         if (abortRef.current.aborted) return
         update(m => ({ ...m, response: (m.response ?? '') + text }))
diff --git a/src/hooks/useAppCommands.ts b/src/hooks/useAppCommands.ts
index c996adb5..2113bbcf 100644
--- a/src/hooks/useAppCommands.ts
+++ b/src/hooks/useAppCommands.ts
@@ -49,6 +49,7 @@ interface AppCommandsConfig {
   onSwitchTheme?: (themeId: string) => void
   onCreateTheme?: () => void
   onOpenVault?: () => void
+  onToggleAIChat?: () => void
 }
 
 /** Sets up keyboard shortcuts, command registry, menu events, and keyboard navigation. */
@@ -69,6 +70,7 @@ export function useAppCommands(config: AppCommandsConfig): CommandAction[] {
     onZoomReset: config.onZoomReset,
     onGoBack: config.onGoBack,
     onGoForward: config.onGoForward,
+    onToggleAIChat: config.onToggleAIChat,
     activeTabPathRef: config.activeTabPathRef,
     handleCloseTabRef: config.handleCloseTabRef,
   })
@@ -126,6 +128,7 @@ export function useAppCommands(config: AppCommandsConfig): CommandAction[] {
     onSwitchTheme: config.onSwitchTheme,
     onCreateTheme: config.onCreateTheme,
     onOpenVault: config.onOpenVault,
+    onToggleAIChat: config.onToggleAIChat,
   })
 
   useKeyboardNavigation({
diff --git a/src/hooks/useAppKeyboard.test.ts b/src/hooks/useAppKeyboard.test.ts
index 4d45563d..a931e20c 100644
--- a/src/hooks/useAppKeyboard.test.ts
+++ b/src/hooks/useAppKeyboard.test.ts
@@ -182,4 +182,22 @@ describe('useAppKeyboard', () => {
     fireKey('0', { metaKey: true })
     expect(actions.onZoomReset).toHaveBeenCalled()
   })
+
+  it('Cmd+I triggers toggle AI chat', () => {
+    const actions = makeActions()
+    const onToggleAIChat = vi.fn()
+    renderHook(() => useAppKeyboard({ ...actions, onToggleAIChat }))
+    fireKey('i', { metaKey: true })
+    expect(onToggleAIChat).toHaveBeenCalled()
+  })
+
+  it('Cmd+I works when text input is focused', () => {
+    const actions = makeActions()
+    const onToggleAIChat = vi.fn()
+    renderHook(() => useAppKeyboard({ ...actions, onToggleAIChat }))
+    withFocusedInput(() => {
+      fireKey('i', { metaKey: true })
+      expect(onToggleAIChat).toHaveBeenCalled()
+    })
+  })
 })
diff --git a/src/hooks/useAppKeyboard.ts b/src/hooks/useAppKeyboard.ts
index 9827816e..31088cfd 100644
--- a/src/hooks/useAppKeyboard.ts
+++ b/src/hooks/useAppKeyboard.ts
@@ -17,6 +17,7 @@ interface KeyboardActions {
   onZoomReset: () => void
   onGoBack?: () => void
   onGoForward?: () => void
+  onToggleAIChat?: () => void
   activeTabPathRef: React.MutableRefObject<string | null>
   handleCloseTabRef: React.MutableRefObject<(path: string) => void>
 }
@@ -62,7 +63,7 @@ function handleCmdKey(e: KeyboardEvent, keyMap: Record<string, ShortcutHandler>)
 
 export function useAppKeyboard({
   onQuickOpen, onCommandPalette, onSearch, onCreateNote, onOpenDailyNote, onSave, onOpenSettings, onTrashNote, onArchiveNote,
-  onSetViewMode, onZoomIn, onZoomOut, onZoomReset, onGoBack, onGoForward, activeTabPathRef, handleCloseTabRef,
+  onSetViewMode, onZoomIn, onZoomOut, onZoomReset, onGoBack, onGoForward, onToggleAIChat, activeTabPathRef, handleCloseTabRef,
 }: KeyboardActions) {
   useEffect(() => {
     const withActiveTab = (fn: (path: string) => void): ShortcutHandler => () => {
@@ -87,6 +88,7 @@ export function useAppKeyboard({
       '+': onZoomIn,
       '-': onZoomOut,
       '0': onZoomReset,
+      i: () => onToggleAIChat?.(),
     }
 
     const handleKeyDown = (e: KeyboardEvent) => {
@@ -102,5 +104,5 @@ export function useAppKeyboard({
     }
     window.addEventListener('keydown', handleKeyDown)
     return () => window.removeEventListener('keydown', handleKeyDown)
-  }, [onQuickOpen, onCommandPalette, onSearch, onCreateNote, onOpenDailyNote, onSave, onOpenSettings, onTrashNote, onArchiveNote, activeTabPathRef, handleCloseTabRef, onSetViewMode, onZoomIn, onZoomOut, onZoomReset, onGoBack, onGoForward])
+  }, [onQuickOpen, onCommandPalette, onSearch, onCreateNote, onOpenDailyNote, onSave, onOpenSettings, onTrashNote, onArchiveNote, activeTabPathRef, handleCloseTabRef, onSetViewMode, onZoomIn, onZoomOut, onZoomReset, onGoBack, onGoForward, onToggleAIChat])
 }
diff --git a/src/hooks/useCommandRegistry.test.ts b/src/hooks/useCommandRegistry.test.ts
index 06de873a..6055a0bd 100644
--- a/src/hooks/useCommandRegistry.test.ts
+++ b/src/hooks/useCommandRegistry.test.ts
@@ -52,6 +52,7 @@ function makeConfig(overrides: Record<string, unknown> = {}) {
     zoomLevel: 100,
     onSelect: vi.fn(),
     onCloseTab: vi.fn(),
+    onOpenDailyNote: vi.fn(),
     ...overrides,
   }
 }
@@ -176,6 +177,23 @@ describe('useCommandRegistry', () => {
     expect(result.current.find(c => c.id === 'zoom-in')!.label).toContain('120%')
   })
 
+  it('has toggle-ai-chat command with shortcut', () => {
+    const onToggleAIChat = vi.fn()
+    const { result } = renderHook(() => useCommandRegistry(makeConfig({ onToggleAIChat })))
+    const cmd = result.current.find(c => c.id === 'toggle-ai-chat')
+    expect(cmd).toBeDefined()
+    expect(cmd!.shortcut).toBe('⌘I')
+    expect(cmd!.group).toBe('View')
+    expect(cmd!.enabled).toBe(true)
+  })
+
+  it('calls onToggleAIChat when toggle-ai-chat executes', () => {
+    const onToggleAIChat = vi.fn()
+    const { result } = renderHook(() => useCommandRegistry(makeConfig({ onToggleAIChat })))
+    result.current.find(c => c.id === 'toggle-ai-chat')!.execute()
+    expect(onToggleAIChat).toHaveBeenCalled()
+  })
+
   it('has open-daily-note command with shortcut', () => {
     const { result } = renderHook(() => useCommandRegistry(makeConfig()))
     const cmd = result.current.find(c => c.id === 'open-daily-note')
diff --git a/src/hooks/useCommandRegistry.ts b/src/hooks/useCommandRegistry.ts
index bf21ff32..318c1394 100644
--- a/src/hooks/useCommandRegistry.ts
+++ b/src/hooks/useCommandRegistry.ts
@@ -31,6 +31,7 @@ interface CommandRegistryConfig {
   onCommitPush: () => void
   onSetViewMode: (mode: ViewMode) => void
   onToggleInspector: () => void
+  onToggleAIChat?: () => void
   onZoomIn: () => void
   onZoomOut: () => void
   onZoomReset: () => void
@@ -128,7 +129,7 @@ export function useCommandRegistry(config: CommandRegistryConfig): CommandAction
     activeTabPath, entries, modifiedCount,
     onQuickOpen, onCreateNote, onCreateNoteOfType, onSave, onOpenSettings,
     onTrashNote, onArchiveNote, onUnarchiveNote,
-    onCommitPush, onSetViewMode, onToggleInspector, onOpenVault,
+    onCommitPush, onSetViewMode, onToggleInspector, onToggleAIChat, onOpenVault,
     onZoomIn, onZoomOut, onZoomReset, zoomLevel,
     onSelect, onOpenDailyNote, onCloseTab,
     onGoBack, onGoForward, canGoBack, canGoForward,
@@ -178,6 +179,7 @@ export function useCommandRegistry(config: CommandRegistryConfig): CommandAction
       { id: 'view-editor-list', label: 'Editor + Note List', group: 'View', shortcut: '⌘2', keywords: ['layout'], enabled: true, execute: () => onSetViewMode('editor-list') },
       { id: 'view-all', label: 'Full Layout', group: 'View', shortcut: '⌘3', keywords: ['layout', 'sidebar'], enabled: true, execute: () => onSetViewMode('all') },
       { id: 'toggle-inspector', label: 'Toggle Inspector', group: 'View', keywords: ['properties', 'panel', 'right'], enabled: true, execute: onToggleInspector },
+      { id: 'toggle-ai-chat', label: 'Toggle AI Chat', group: 'View', shortcut: '⌘I', keywords: ['ai', 'agent', 'chat', 'assistant', 'contextual'], enabled: true, execute: () => onToggleAIChat?.() },
       { id: 'zoom-in', label: `Zoom In (${zoomLevel}%)`, group: 'View', shortcut: '⌘=', keywords: ['zoom', 'bigger', 'larger', 'scale'], enabled: zoomLevel < 150, execute: onZoomIn },
       { id: 'zoom-out', label: `Zoom Out (${zoomLevel}%)`, group: 'View', shortcut: '⌘-', keywords: ['zoom', 'smaller', 'scale'], enabled: zoomLevel > 80, execute: onZoomOut },
       { id: 'zoom-reset', label: 'Reset Zoom', group: 'View', shortcut: '⌘0', keywords: ['zoom', 'actual', 'default', '100'], enabled: zoomLevel !== 100, execute: onZoomReset },
@@ -198,7 +200,7 @@ export function useCommandRegistry(config: CommandRegistryConfig): CommandAction
     hasActiveNote, activeTabPath, isArchived, modifiedCount,
     onQuickOpen, onCreateNote, onCreateNoteOfType, onSave, onOpenSettings,
     onTrashNote, onArchiveNote, onUnarchiveNote,
-    onCommitPush, onSetViewMode, onToggleInspector, onOpenVault,
+    onCommitPush, onSetViewMode, onToggleInspector, onToggleAIChat, onOpenVault,
     onZoomIn, onZoomOut, onZoomReset, zoomLevel,
     onSelect, onOpenDailyNote, onCloseTab,
     onGoBack, onGoForward, canGoBack, canGoForward,
diff --git a/src/utils/ai-context.test.ts b/src/utils/ai-context.test.ts
new file mode 100644
index 00000000..d9d37d32
--- /dev/null
+++ b/src/utils/ai-context.test.ts
@@ -0,0 +1,185 @@
+import { describe, it, expect } from 'vitest'
+import { resolveTarget, collectLinkedEntries, buildContextualPrompt } from './ai-context'
+import type { VaultEntry } from '../types'
+
+const makeEntry = (overrides: Partial<VaultEntry> = {}): VaultEntry => ({
+  path: '/vault/note/test.md',
+  filename: 'test.md',
+  title: 'Test Note',
+  isA: 'Note',
+  aliases: [],
+  belongsTo: [],
+  relatedTo: [],
+  status: null,
+  owner: null,
+  cadence: null,
+  archived: false,
+  trashed: false,
+  trashedAt: null,
+  modifiedAt: 1700000000,
+  createdAt: 1700000000,
+  fileSize: 100,
+  snippet: '',
+  wordCount: 0,
+  relationships: {},
+  icon: null,
+  color: null,
+  order: null,
+  outgoingLinks: [],
+  ...overrides,
+})
+
+describe('resolveTarget', () => {
+  const entries = [
+    makeEntry({ path: '/vault/a.md', title: 'Alpha', filename: 'a.md' }),
+    makeEntry({ path: '/vault/b.md', title: 'Beta', filename: 'beta-note.md', aliases: ['B'] }),
+  ]
+
+  it('resolves by title (case-insensitive)', () => {
+    expect(resolveTarget('alpha', entries)?.path).toBe('/vault/a.md')
+    expect(resolveTarget('Alpha', entries)?.path).toBe('/vault/a.md')
+  })
+
+  it('resolves by alias (case-insensitive)', () => {
+    expect(resolveTarget('B', entries)?.path).toBe('/vault/b.md')
+    expect(resolveTarget('b', entries)?.path).toBe('/vault/b.md')
+  })
+
+  it('resolves by filename stem', () => {
+    expect(resolveTarget('beta-note', entries)?.path).toBe('/vault/b.md')
+  })
+
+  it('returns undefined for unresolvable target', () => {
+    expect(resolveTarget('nonexistent', entries)).toBeUndefined()
+  })
+})
+
+describe('collectLinkedEntries', () => {
+  const entryA = makeEntry({ path: '/vault/a.md', title: 'Alpha' })
+  const entryB = makeEntry({ path: '/vault/b.md', title: 'Beta' })
+  const entryC = makeEntry({ path: '/vault/c.md', title: 'Gamma' })
+  const entryD = makeEntry({ path: '/vault/d.md', title: 'Delta' })
+  const allEntries = [entryA, entryB, entryC, entryD]
+
+  it('returns empty array when active has no links', () => {
+    expect(collectLinkedEntries(entryA, allEntries)).toEqual([])
+  })
+
+  it('collects entries from outgoingLinks', () => {
+    const active = makeEntry({
+      path: '/vault/main.md', title: 'Main',
+      outgoingLinks: ['Alpha', 'Beta'],
+    })
+    const linked = collectLinkedEntries(active, [...allEntries, active])
+    expect(linked.map(e => e.title)).toEqual(['Alpha', 'Beta'])
+  })
+
+  it('collects entries from relationships', () => {
+    const active = makeEntry({
+      path: '/vault/main.md', title: 'Main',
+      relationships: { relatedTo: ['[[Alpha]]', '[[Gamma]]'] },
+    })
+    const linked = collectLinkedEntries(active, [...allEntries, active])
+    expect(linked.map(e => e.title)).toEqual(['Alpha', 'Gamma'])
+  })
+
+  it('collects entries from belongsTo', () => {
+    const active = makeEntry({
+      path: '/vault/main.md', title: 'Main',
+      belongsTo: ['[[Delta]]'],
+    })
+    const linked = collectLinkedEntries(active, [...allEntries, active])
+    expect(linked.map(e => e.title)).toEqual(['Delta'])
+  })
+
+  it('collects entries from relatedTo', () => {
+    const active = makeEntry({
+      path: '/vault/main.md', title: 'Main',
+      relatedTo: ['[[Beta]]'],
+    })
+    const linked = collectLinkedEntries(active, [...allEntries, active])
+    expect(linked.map(e => e.title)).toEqual(['Beta'])
+  })
+
+  it('deduplicates entries across all link sources', () => {
+    const active = makeEntry({
+      path: '/vault/main.md', title: 'Main',
+      outgoingLinks: ['Alpha', 'Beta'],
+      relationships: { people: ['[[Alpha]]'] },
+      belongsTo: ['[[Beta]]'],
+      relatedTo: ['[[Alpha]]'],
+    })
+    const linked = collectLinkedEntries(active, [...allEntries, active])
+    expect(linked.map(e => e.title)).toEqual(['Alpha', 'Beta'])
+  })
+
+  it('excludes the active note itself', () => {
+    const active = makeEntry({
+      path: '/vault/a.md', title: 'Alpha',
+      outgoingLinks: ['Alpha'],
+    })
+    const linked = collectLinkedEntries(active, allEntries)
+    expect(linked).toEqual([])
+  })
+
+  it('ignores unresolvable links', () => {
+    const active = makeEntry({
+      path: '/vault/main.md', title: 'Main',
+      outgoingLinks: ['Alpha', 'Nonexistent'],
+    })
+    const linked = collectLinkedEntries(active, [...allEntries, active])
+    expect(linked.map(e => e.title)).toEqual(['Alpha'])
+  })
+})
+
+describe('buildContextualPrompt', () => {
+  it('includes active note title and content', () => {
+    const active = makeEntry({ path: '/vault/a.md', title: 'Alpha', isA: 'Project' })
+    const content = { '/vault/a.md': '# Alpha\nThis is the alpha project.' }
+    const prompt = buildContextualPrompt(active, [], content)
+    expect(prompt).toContain('Alpha')
+    expect(prompt).toContain('Project')
+    expect(prompt).toContain('This is the alpha project.')
+  })
+
+  it('includes linked note content', () => {
+    const active = makeEntry({ path: '/vault/a.md', title: 'Alpha' })
+    const linked = makeEntry({ path: '/vault/b.md', title: 'Beta', isA: 'Person' })
+    const content = {
+      '/vault/a.md': '# Alpha\nMain note.',
+      '/vault/b.md': '# Beta\nLinked person.',
+    }
+    const prompt = buildContextualPrompt(active, [linked], content)
+    expect(prompt).toContain('Beta')
+    expect(prompt).toContain('Person')
+    expect(prompt).toContain('Linked person.')
+    expect(prompt).toContain('Linked Notes')
+  })
+
+  it('shows (no content) when content is missing', () => {
+    const active = makeEntry({ path: '/vault/a.md', title: 'Alpha' })
+    const prompt = buildContextualPrompt(active, [], {})
+    expect(prompt).toContain('(no content)')
+  })
+
+  it('truncates linked note content to 2000 chars', () => {
+    const active = makeEntry({ path: '/vault/a.md', title: 'Alpha' })
+    const linked = makeEntry({ path: '/vault/b.md', title: 'Beta' })
+    const longContent = 'x'.repeat(3000)
+    const content = {
+      '/vault/a.md': '# Alpha',
+      '/vault/b.md': longContent,
+    }
+    const prompt = buildContextualPrompt(active, [linked], content)
+    // The linked note content should be truncated
+    const betaIdx = prompt.indexOf('### Beta')
+    const afterBeta = prompt.slice(betaIdx)
+    expect(afterBeta.length).toBeLessThan(2200)
+  })
+
+  it('includes the system preamble', () => {
+    const active = makeEntry({ path: '/vault/a.md', title: 'Alpha' })
+    const prompt = buildContextualPrompt(active, [], { '/vault/a.md': 'content' })
+    expect(prompt).toContain('AI assistant integrated into Laputa')
+  })
+})
diff --git a/src/utils/ai-context.ts b/src/utils/ai-context.ts
new file mode 100644
index 00000000..0b0c4a99
--- /dev/null
+++ b/src/utils/ai-context.ts
@@ -0,0 +1,90 @@
+/**
+ * AI contextual chat — builds the context note list from the active note
+ * and its first-degree linked notes (outgoingLinks + relationships).
+ */
+
+import type { VaultEntry } from '../types'
+import { wikilinkTarget } from './wikilink'
+
+/** Resolve a link target string to a VaultEntry by matching title, aliases, or filename stem. */
+export function resolveTarget(target: string, entries: VaultEntry[]): VaultEntry | undefined {
+  const lower = target.toLowerCase()
+  return entries.find(e => {
+    if (e.title.toLowerCase() === lower) return true
+    if (e.aliases.some(a => a.toLowerCase() === lower)) return true
+    const stem = e.filename.replace(/\.md$/, '')
+    if (stem.toLowerCase() === lower) return true
+    return false
+  })
+}
+
+/** Collect first-degree linked notes from the active entry. */
+export function collectLinkedEntries(
+  active: VaultEntry,
+  entries: VaultEntry[],
+): VaultEntry[] {
+  const seen = new Set<string>([active.path])
+  const linked: VaultEntry[] = []
+
+  const addTarget = (target: string) => {
+    const entry = resolveTarget(target, entries)
+    if (entry && !seen.has(entry.path)) {
+      seen.add(entry.path)
+      linked.push(entry)
+    }
+  }
+
+  // outgoingLinks are raw targets (no [[ ]] wrapper)
+  for (const target of active.outgoingLinks) {
+    addTarget(target)
+  }
+
+  // relationships values are wikilink references like [[target]]
+  for (const refs of Object.values(active.relationships)) {
+    for (const ref of refs) {
+      addTarget(wikilinkTarget(ref))
+    }
+  }
+
+  // belongsTo and relatedTo are also wikilink references
+  for (const ref of active.belongsTo) {
+    addTarget(wikilinkTarget(ref))
+  }
+  for (const ref of active.relatedTo) {
+    addTarget(wikilinkTarget(ref))
+  }
+
+  return linked
+}
+
+/** Build a contextual system prompt from the active note and its linked notes. */
+export function buildContextualPrompt(
+  active: VaultEntry,
+  linkedEntries: VaultEntry[],
+  allContent: Record<string, string>,
+): string {
+  const parts: string[] = [
+    'You are an AI assistant integrated into Laputa, a personal knowledge management app.',
+    'The user is viewing a specific note. Use the note and its linked context to answer questions accurately.',
+    'You can also use MCP tools to search, read, create, or edit notes in the vault.',
+    '',
+    `## Active Note: ${active.title}`,
+    `Type: ${active.isA ?? 'Note'} | Path: ${active.path}`,
+    '',
+    allContent[active.path] ?? '(no content)',
+  ]
+
+  if (linkedEntries.length > 0) {
+    parts.push('', '## Linked Notes')
+    for (const entry of linkedEntries) {
+      const content = allContent[entry.path]
+      parts.push(
+        '',
+        `### ${entry.title} (${entry.isA ?? 'Note'})`,
+        content ? content.slice(0, 2000) : '(no content loaded)',
+      )
+    }
+  }
+
+  return parts.join('\n')
+}