diff --git a/packages/app/src/app/providers.tsx b/packages/app/src/app/providers.tsx
index b52e248..d596ae5 100644
--- a/packages/app/src/app/providers.tsx
+++ b/packages/app/src/app/providers.tsx
@@ -5,6 +5,7 @@ import { FluentProvider } from '@fluentui/react-components';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { originmainLightTheme, originmainDarkTheme } from '@originmain/ui';
 import { useTheme } from '@/store/theme';
+import { TourOverlay } from '@/components/walkthrough/TourOverlay';
 
 export function Providers({ children }: { children: ReactNode }) {
   // TanStack Query v5: create QueryClient inside useState so it's stable across
@@ -35,6 +36,7 @@ export function Providers({ children }: { children: ReactNode }) {
     <QueryClientProvider client={queryClient}>
       <FluentProvider theme={theme} style={{ height: '100%' }}>
         {children}
+        <TourOverlay />
       </FluentProvider>
     </QueryClientProvider>
   );
diff --git a/packages/app/src/app/workspace/[wid]/page.tsx b/packages/app/src/app/workspace/[wid]/page.tsx
index a811f3c..6b00409 100644
--- a/packages/app/src/app/workspace/[wid]/page.tsx
+++ b/packages/app/src/app/workspace/[wid]/page.tsx
@@ -5,6 +5,7 @@ import { serverClient } from '@/lib/supabase';
 import { AppHeader } from '@/components/shell/AppHeader';
 import { ProjectCard } from '@/components/shell/ProjectCard';
 import { DesignLanguageUpload } from '@/components/shell/DesignLanguageUpload';
+import { TourAutoStart } from '@/components/walkthrough/TourAutoStart';
 import { getActiveDesignLanguageFile } from '@originmain/origin-graph';
 import type { Workspace, Project } from '@originmain/origin-graph';
 
@@ -47,6 +48,8 @@ export default async function WorkspacePage({ params }: { params: Promise<{ wid:
 
   return (
     <div style={{ minHeight: '100dvh', background: 'var(--page-bg)', fontFamily: "'Inter', -apple-system, sans-serif" }}>
+      {/* Auto-start tour for first-time visitors (client component, renders null) */}
+      <TourAutoStart />
       <AppHeader breadcrumbs={[
         { label: 'Workspaces', href: '/workspaces' },
         { label: workspace.name },
@@ -54,8 +57,8 @@ export default async function WorkspacePage({ params }: { params: Promise<{ wid:
 
       <main style={{ maxWidth: 960, margin: '0 auto', padding: '48px 24px' }}>
 
-        {/* Title row */}
-        <div style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 32 }}>
+        {/* Title row — data-tour="projects-section" anchors the tour spotlight */}
+        <div data-tour="projects-section" style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', marginBottom: 32 }}>
           <div>
             <h1 style={{ fontSize: '1.5rem', fontWeight: 700, letterSpacing: '-0.03em', color: 'var(--page-text)', margin: 0 }}>
               Projects
@@ -92,13 +95,16 @@ export default async function WorkspacePage({ params }: { params: Promise<{ wid:
               </svg>
               Settings
             </Link>
-            <Link href={`/workspace/${wid}/project/new`} style={{
-              display: 'inline-flex', alignItems: 'center', gap: 6,
-              background: 'var(--btn-bg)', color: 'var(--btn-fg)',
-              fontSize: '0.875rem', fontWeight: 600,
-              padding: '9px 18px', borderRadius: 9,
-              textDecoration: 'none', letterSpacing: '-0.01em',
-            }}>
+            <Link
+              href={`/workspace/${wid}/project/new`}
+              data-tour="new-project-btn"
+              style={{
+                display: 'inline-flex', alignItems: 'center', gap: 6,
+                background: 'var(--btn-bg)', color: 'var(--btn-fg)',
+                fontSize: '0.875rem', fontWeight: 600,
+                padding: '9px 18px', borderRadius: 9,
+                textDecoration: 'none', letterSpacing: '-0.01em',
+              }}>
               <svg width="14" height="14" viewBox="0 0 14 14" fill="none">
                 <path d="M7 1v12M1 7h12" stroke="currentColor" strokeWidth="1.6" strokeLinecap="round"/>
               </svg>
diff --git a/packages/app/src/components/canvas/Artboard.tsx b/packages/app/src/components/canvas/Artboard.tsx
index 51b9156..6d7e99a 100644
--- a/packages/app/src/components/canvas/Artboard.tsx
+++ b/packages/app/src/components/canvas/Artboard.tsx
@@ -28,7 +28,11 @@ const DIFF_STATUS_BADGE: Record<string, { color: string; bg: string; label: stri
 };
 
 export function Artboard({ id, label, x, y, width, height, renderUrl }: ArtboardProps) {
-  const { selectedArtboardId, selectArtboard, workspaceId, projectId, setArtboardLive, setFiberRoot, selectComponent } = useCanvas();
+  const {
+    selectedArtboardId, selectArtboard, workspaceId, projectId,
+    setArtboardLive, setFiberRoot, selectComponent,
+    selectedComponentId,
+  } = useCanvas();
   const selected = selectedArtboardId === id;
   const queryClient = useQueryClient();
 
@@ -305,6 +309,7 @@ export function Artboard({ id, label, x, y, width, height, renderUrl }: Artboard
               src={renderUrl}
               width={width}
               height={height}
+              selectedComponentId={selectedComponentId}
               onFiberTreeUpdate={handleFiberUpdate}
               onComponentSelected={handleComponentSelected}
             />
@@ -360,6 +365,7 @@ function EmptyArtboardContent({
 
   return (
     <div
+      data-tour="artboard-empty"
       style={{
         width, height, display: 'flex', flexDirection: 'column',
         alignItems: 'center', justifyContent: 'center',
@@ -432,6 +438,7 @@ function EmptyArtboardContent({
             npx @originmain/cli dev --target :3000
           </p>
           <button
+            data-tour="artboard-url-btn"
             onClick={() => setEditing(true)}
             style={{
               padding: '7px 14px', borderRadius: 6, border: '1px solid rgba(0,0,0,0.12)',
diff --git a/packages/app/src/components/canvas/LiveArtboard.tsx b/packages/app/src/components/canvas/LiveArtboard.tsx
index ddaea3e..205bfd7 100644
--- a/packages/app/src/components/canvas/LiveArtboard.tsx
+++ b/packages/app/src/components/canvas/LiveArtboard.tsx
@@ -17,7 +17,12 @@ export interface LiveArtboardProps {
   src: string;
   width?: number;
   height?: number;
+  /** DLF design tokens to inject into the iframe as CSS custom properties. */
   designTokens?: Record<string, string>;
+  /** The currently selected component node ID (from the canvas store).
+   *  When set, sends SELECT_COMPONENT to the iframe so the fiber hook renders
+   *  a blue highlight ring over that component's DOM element. */
+  selectedComponentId?: string | null;
   onReady?: () => void;
   onFiberTreeUpdate?: (root: FiberNode) => void;
   onComponentSelected?: (nodeId: string) => void;
@@ -32,25 +37,31 @@ export function LiveArtboard({
   width = 1280,
   height = 720,
   designTokens,
+  selectedComponentId,
   onReady,
   onFiberTreeUpdate,
   onComponentSelected,
   style,
 }: LiveArtboardProps) {
   const iframeRef = useRef<HTMLIFrameElement>(null);
+  // Track whether the iframe has sent READY so we don't send messages too early.
+  const isReadyRef = useRef(false);
 
-  // Send a message to the iframe via the typed protocol
+  // ── Send a typed message to the iframe ───────────────────────────────────
   const sendMessage = useCallback(
     (type: Parameters<typeof createHostEnvelope>[1]['type'], payload?: Record<string, unknown>) => {
       const iframe = iframeRef.current;
       if (!iframe?.contentWindow) return;
-      const envelope = createHostEnvelope(id, { type, ...(payload ?? {}) } as Parameters<typeof createHostEnvelope>[1]);
+      const envelope = createHostEnvelope(
+        id,
+        { type, ...(payload ?? {}) } as Parameters<typeof createHostEnvelope>[1],
+      );
       iframe.contentWindow.postMessage(envelope, '*');
     },
-    [id]
+    [id],
   );
 
-  // Handle messages from the renderer iframe
+  // ── Handle messages from the renderer iframe ──────────────────────────────
   useEffect(() => {
     function handleMessage(event: MessageEvent) {
       if (!isRendererEnvelope(event.data)) return;
@@ -59,10 +70,13 @@ export function LiveArtboard({
       const msg: RendererMessage = event.data.message;
       switch (msg.type) {
         case 'READY':
-          // The fiber hook is already installed — either by the CLI proxy
-          // (injected into the HTML response) or by @originmain/live SDK
-          // (imported before React in the user's app). No injection needed.
+          isReadyRef.current = true;
+          // Push current design tokens into the iframe immediately.
           if (designTokens) sendMessage('SET_DESIGN_TOKENS', { tokens: designTokens });
+          // Restore any active selection that existed before the iframe loaded.
+          if (selectedComponentId) {
+            sendMessage('SELECT_COMPONENT', { nodeId: selectedComponentId });
+          }
           onReady?.();
           break;
         case 'FIBER_TREE_UPDATE':
@@ -76,26 +90,39 @@ export function LiveArtboard({
 
     window.addEventListener('message', handleMessage);
     return () => window.removeEventListener('message', handleMessage);
-  }, [id, designTokens, sendMessage, onReady, onFiberTreeUpdate, onComponentSelected]);
+  }, [id, designTokens, selectedComponentId, sendMessage, onReady, onFiberTreeUpdate, onComponentSelected]);
 
-  // Push updated design tokens whenever they change
+  // ── Push updated design tokens whenever they change ───────────────────────
   useEffect(() => {
-    if (!designTokens) return;
+    if (!isReadyRef.current || !designTokens) return;
     sendMessage('SET_DESIGN_TOKENS', { tokens: designTokens });
   }, [designTokens, sendMessage]);
 
+  // ── Sync selection changes into the iframe ────────────────────────────────
+  // Sends SELECT_COMPONENT on every selectedComponentId change so the blue
+  // highlight ring stays in sync with the canvas selection store.
+  useEffect(() => {
+    if (!isReadyRef.current) return;
+    if (selectedComponentId) {
+      sendMessage('SELECT_COMPONENT', { nodeId: selectedComponentId });
+    } else {
+      sendMessage('DESELECT');
+    }
+  }, [selectedComponentId, sendMessage]);
+
   return (
     <iframe
       ref={iframeRef}
       // The name attribute carries the artboard ID to the fiber hook.
-      // The hook reads window.name to tag postMessage envelopes.
+      // The hook reads window.name to tag postMessage envelopes and to
+      // guard against activating outside Originmain iframes.
       // Format: "om:<artboardId>"
       name={`om:${id}`}
       src={src}
       title={`artboard-${id}`}
-      // Security: allow-scripts required to run React; allow-same-origin required
-      // for postMessage with targeted origin validation. Do NOT combine these with
-      // untrusted third-party content.
+      // Security: allow-scripts required for React; allow-same-origin required
+      // for postMessage origin validation. Do NOT add allow-top-navigation or
+      // allow-popups unless explicitly needed — principle of least privilege.
       sandbox="allow-scripts allow-same-origin allow-forms"
       style={{
         width,
diff --git a/packages/app/src/components/chrome/AppChrome.tsx b/packages/app/src/components/chrome/AppChrome.tsx
index 261d897..651044c 100644
--- a/packages/app/src/components/chrome/AppChrome.tsx
+++ b/packages/app/src/components/chrome/AppChrome.tsx
@@ -12,6 +12,7 @@ import { useCanvas, type Tool } from '@/store/canvas';
 import { useViewport } from '@/store/viewport';
 import { useTheme } from '@/store/theme';
 import { useCanvasTheme } from '@/store/canvasTheme';
+import { useWalkthrough } from '@/store/walkthrough';
 
 interface AppChromeProps {
   workspaceId?: string;
@@ -26,6 +27,7 @@ export function AppChrome({ workspaceId, projectId, workspaceName, projectName }
   const setActiveTool      = useCanvas((s) => s.setActiveTool);
   const { mode: themeMode, toggle: toggleTheme } = useTheme();
   const CT = useCanvasTheme();
+  const startTour = useWalkthrough((s) => s.start);
 
   // Push workspace/project IDs into the store so Canvas and Navigator can read them.
   useEffect(() => {
@@ -168,6 +170,36 @@ export function AppChrome({ workspaceId, projectId, workspaceName, projectName }
 
           <div style={{ flex: 1 }} />
 
+          {/* Tour trigger */}
+          <button
+            onClick={startTour}
+            title="Start product tour"
+            aria-label="Start product tour"
+            style={{
+              background: 'none',
+              border: `1px solid ${CT.border}`,
+              cursor: 'pointer',
+              color: CT.fgMuted,
+              width: 22, height: 22, borderRadius: '50%',
+              display: 'flex', alignItems: 'center', justifyContent: 'center',
+              fontSize: '0.6875rem', fontWeight: 600, marginRight: 6,
+              transition: 'color 0.12s, background 0.12s, border-color 0.12s',
+              flexShrink: 0,
+            }}
+            onMouseEnter={e => {
+              e.currentTarget.style.color = CT.accent;
+              e.currentTarget.style.borderColor = `${CT.accent}66`;
+              e.currentTarget.style.background = `${CT.accent}14`;
+            }}
+            onMouseLeave={e => {
+              e.currentTarget.style.color = CT.fgMuted;
+              e.currentTarget.style.borderColor = CT.border;
+              e.currentTarget.style.background = 'none';
+            }}
+          >
+            ?
+          </button>
+
           {/* Theme toggle */}
           <button
             onClick={toggleTheme}
diff --git a/packages/app/src/components/inspector/Inspector.tsx b/packages/app/src/components/inspector/Inspector.tsx
index a862c22..4f64246 100644
--- a/packages/app/src/components/inspector/Inspector.tsx
+++ b/packages/app/src/components/inspector/Inspector.tsx
@@ -29,6 +29,7 @@ export function Inspector() {
 
   return (
     <div
+      data-tour="inspector-panel"
       className="dark-panel"
       style={{
         gridColumn: 3,
diff --git a/packages/app/src/components/navigator/ArtboardNavigator.tsx b/packages/app/src/components/navigator/ArtboardNavigator.tsx
index 5cb2983..eef20ce 100644
--- a/packages/app/src/components/navigator/ArtboardNavigator.tsx
+++ b/packages/app/src/components/navigator/ArtboardNavigator.tsx
@@ -109,6 +109,7 @@ export function ArtboardNavigator() {
 
   return (
     <div
+      data-tour="navigator-panel"
       className="dark-panel"
       style={{
         gridColumn: 1,
diff --git a/packages/app/src/components/shell/AppHeader.tsx b/packages/app/src/components/shell/AppHeader.tsx
index 3506806..e000161 100644
--- a/packages/app/src/components/shell/AppHeader.tsx
+++ b/packages/app/src/components/shell/AppHeader.tsx
@@ -3,6 +3,7 @@
 import Link from 'next/link';
 import { UserButton } from '@clerk/nextjs';
 import { useTheme } from '@/store/theme';
+import { useWalkthrough } from '@/store/walkthrough';
 
 interface Crumb { label: string; href?: string }
 
@@ -16,6 +17,7 @@ interface AppHeaderProps {
 
 export function AppHeader({ breadcrumbs = [], workspaceName, workspaceId }: AppHeaderProps) {
   const { mode, toggle } = useTheme();
+  const startTour = useWalkthrough((s) => s.start);
 
   // Back-compat: if old props are passed without breadcrumbs, synthesise them
   const crumbs: Crumb[] = breadcrumbs.length > 0
@@ -73,6 +75,34 @@ export function AppHeader({ breadcrumbs = [], workspaceName, workspaceId }: AppH
 
       <div style={{ flex: 1 }} />
 
+      {/* Tour trigger */}
+      <button
+        onClick={startTour}
+        title="Start product tour"
+        aria-label="Start product tour"
+        style={{
+          background: 'none', border: `1px solid ${mode === 'dark' ? 'rgba(255,255,255,0.12)' : 'rgba(0,0,0,0.10)'}`,
+          cursor: 'pointer',
+          color: mode === 'dark' ? 'rgba(255,255,255,0.4)' : '#A1A1AA',
+          width: 26, height: 26, borderRadius: '50%',
+          display: 'flex', alignItems: 'center', justifyContent: 'center',
+          fontSize: '0.75rem', fontWeight: 600, marginRight: 8,
+          transition: 'color 0.12s, background 0.12s, border-color 0.12s',
+        }}
+        onMouseEnter={e => {
+          e.currentTarget.style.color = '#3385FF';
+          e.currentTarget.style.borderColor = 'rgba(51,133,255,0.45)';
+          e.currentTarget.style.background = 'rgba(51,133,255,0.08)';
+        }}
+        onMouseLeave={e => {
+          e.currentTarget.style.color = mode === 'dark' ? 'rgba(255,255,255,0.4)' : '#A1A1AA';
+          e.currentTarget.style.borderColor = mode === 'dark' ? 'rgba(255,255,255,0.12)' : 'rgba(0,0,0,0.10)';
+          e.currentTarget.style.background = 'none';
+        }}
+      >
+        ?
+      </button>
+
       {/* Theme toggle */}
       <button
         onClick={toggle}
diff --git a/packages/app/src/components/shell/ProjectCard.tsx b/packages/app/src/components/shell/ProjectCard.tsx
index dbdf640..a5ee8a7 100644
--- a/packages/app/src/components/shell/ProjectCard.tsx
+++ b/packages/app/src/components/shell/ProjectCard.tsx
@@ -26,6 +26,7 @@ export function ProjectCard({ workspaceId, projectId, name, framework, appUrl, d
   return (
     <Link href={`/workspace/${workspaceId}/project/${projectId}`} style={{ textDecoration: 'none' }}>
       <div
+        data-tour="project-card"
         style={{
           background: 'var(--card-bg)',
           border: '1px solid var(--card-border)',
diff --git a/packages/app/src/components/walkthrough/TourAutoStart.tsx b/packages/app/src/components/walkthrough/TourAutoStart.tsx
new file mode 100644
index 0000000..125b3d8
--- /dev/null
+++ b/packages/app/src/components/walkthrough/TourAutoStart.tsx
@@ -0,0 +1,39 @@
+'use client';
+
+import { useEffect } from 'react';
+import { useWalkthrough } from '@/store/walkthrough';
+
+/**
+ * Invisible client component that auto-starts the product tour for
+ * first-time visitors.  Renders null — mount it anywhere on the page.
+ *
+ * Logic:
+ *  • Skip if the user has already completed the tour (persisted in localStorage).
+ *  • Skip if the tour is already active.
+ *  • Use a sessionStorage flag so the auto-start fires at most once per
+ *    browser session (prevents re-firing on every client navigation).
+ *  • A 900 ms delay lets the page fully paint before the overlay appears.
+ */
+export function TourAutoStart() {
+  const completed = useWalkthrough((s) => s.completed);
+  const active    = useWalkthrough((s) => s.active);
+  const start     = useWalkthrough((s) => s.start);
+
+  useEffect(() => {
+    // Already done or currently running — nothing to do.
+    if (completed || active) return;
+
+    const FLAG = 'originmain:tour-auto-started';
+    if (typeof sessionStorage !== 'undefined' && sessionStorage.getItem(FLAG)) return;
+
+    // Mark as fired for this session before the timeout so a fast re-render
+    // doesn't double-fire.
+    if (typeof sessionStorage !== 'undefined') sessionStorage.setItem(FLAG, '1');
+
+    const timer = setTimeout(start, 900);
+    return () => clearTimeout(timer);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []); // intentionally empty — run only on first mount
+
+  return null;
+}
diff --git a/packages/app/src/components/walkthrough/TourOverlay.tsx b/packages/app/src/components/walkthrough/TourOverlay.tsx
new file mode 100644
index 0000000..79bd023
--- /dev/null
+++ b/packages/app/src/components/walkthrough/TourOverlay.tsx
@@ -0,0 +1,441 @@
+'use client';
+
+import { useEffect, useState, useCallback } from 'react';
+import { createPortal } from 'react-dom';
+import { useWalkthrough } from '@/store/walkthrough';
+import { TOUR_STEPS } from './tourSteps';
+
+// ── Types ─────────────────────────────────────────────────────────────────────
+
+interface Rect { x: number; y: number; width: number; height: number }
+
+// ── Constants ─────────────────────────────────────────────────────────────────
+
+const TOOLTIP_WIDTH = 340;
+const SPOTLIGHT_PAD = 8;  // px of padding around the spotlight target
+const GAP           = 14; // px gap between spotlight and tooltip card
+
+// ── Component ─────────────────────────────────────────────────────────────────
+
+export function TourOverlay() {
+  const { active, stepIndex, next, prev, dismiss } = useWalkthrough();
+  const [mounted, setMounted]       = useState(false);
+  const [targetRect, setTargetRect] = useState<Rect | null>(null);
+  const [pathMismatch, setPathMismatch] = useState(false);
+
+  // Only render portals after client hydration.
+  useEffect(() => { setMounted(true); }, []);
+
+  const step = TOUR_STEPS[stepIndex];
+
+  // ── Measure the spotlight target element ─────────────────────────────────
+  const measureTarget = useCallback(() => {
+    if (!step) { setTargetRect(null); return; }
+
+    const { targetSelector, requiredPathPart } = step;
+
+    // Check we're on the right page for this step.
+    const onCorrectPage = !requiredPathPart ||
+      window.location.pathname.includes(requiredPathPart);
+    setPathMismatch(!onCorrectPage);
+
+    if (!targetSelector || !onCorrectPage) {
+      setTargetRect(null);
+      return;
+    }
+
+    const el = document.querySelector(targetSelector);
+    if (!el) {
+      setTargetRect(null);
+      return;
+    }
+
+    const r = el.getBoundingClientRect();
+    setTargetRect({ x: r.x, y: r.y, width: r.width, height: r.height });
+  }, [step]);
+
+  useEffect(() => {
+    if (!active) { setTargetRect(null); return; }
+    measureTarget();
+
+    // Re-measure on resize and scroll so the spotlight stays aligned.
+    window.addEventListener('resize', measureTarget);
+    window.addEventListener('scroll', measureTarget, true);
+    return () => {
+      window.removeEventListener('resize', measureTarget);
+      window.removeEventListener('scroll', measureTarget, true);
+    };
+  }, [active, measureTarget]);
+
+  // ── Keyboard navigation ───────────────────────────────────────────────────
+  useEffect(() => {
+    if (!active) return;
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === 'Escape')     { e.preventDefault(); dismiss(); }
+      if (e.key === 'ArrowRight') { e.preventDefault(); next(TOUR_STEPS.length); }
+      if (e.key === 'ArrowLeft')  { e.preventDefault(); prev(); }
+    };
+    window.addEventListener('keydown', onKey);
+    return () => window.removeEventListener('keydown', onKey);
+  }, [active, next, prev, dismiss]);
+
+  // ── Compute tooltip position ──────────────────────────────────────────────
+  const tooltipStyle = computeTooltipPosition(targetRect, step?.placement ?? 'auto');
+
+  if (!mounted || !active || !step) return null;
+
+  const isFirstStep = stepIndex === 0;
+  const isLastStep  = stepIndex === TOUR_STEPS.length - 1;
+  const progress    = ((stepIndex + 1) / TOUR_STEPS.length) * 100;
+
+  // Spotlight rect with padding applied.
+  const spotlight = targetRect ? {
+    x:      targetRect.x      - SPOTLIGHT_PAD,
+    y:      targetRect.y      - SPOTLIGHT_PAD,
+    width:  targetRect.width  + SPOTLIGHT_PAD * 2,
+    height: targetRect.height + SPOTLIGHT_PAD * 2,
+  } : null;
+
+  return createPortal(
+    <>
+      {/* ── Dim backdrop (click outside = dismiss) ─────────────────────── */}
+      <div
+        aria-hidden="true"
+        onClick={dismiss}
+        style={{
+          position: 'fixed', inset: 0,
+          zIndex: 9990,
+          // When there's a spotlight, the backdrop darkness is created by the
+          // spotlight element's box-shadow, so we only need a backdrop when
+          // the tour card is centered (no spotlight).
+          background: spotlight ? 'transparent' : 'rgba(0,0,0,0.55)',
+        }}
+      />
+
+      {/* ── Spotlight ring (box-shadow creates dark outside the rect) ────── */}
+      {spotlight && (
+        <div
+          aria-hidden="true"
+          style={{
+            position:  'fixed',
+            left:      spotlight.x,
+            top:       spotlight.y,
+            width:     spotlight.width,
+            height:    spotlight.height,
+            borderRadius: 8,
+            // 9999px box-shadow fills the entire viewport outside this rect.
+            boxShadow: '0 0 0 9999px rgba(0,0,0,0.55)',
+            border:    '2px solid rgba(51,133,255,0.7)',
+            zIndex:    9991,
+            pointerEvents: 'none',
+            transition: 'all 0.12s ease',
+          }}
+        />
+      )}
+
+      {/* ── Tooltip card ──────────────────────────────────────────────────── */}
+      <div
+        role="dialog"
+        aria-modal="true"
+        aria-label={step.id}
+        style={{
+          position: 'fixed',
+          zIndex:   9999,
+          width:    TOOLTIP_WIDTH,
+          ...tooltipStyle,
+          background:   'var(--card-bg)',
+          border:       '1px solid var(--card-border)',
+          borderRadius: 16,
+          padding:      '22px 24px 20px',
+          boxShadow:    '0 12px 40px rgba(0,0,0,0.22), 0 2px 8px rgba(0,0,0,0.12)',
+          fontFamily:   "'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif",
+        }}
+        // Prevent click from propagating to the backdrop (which would dismiss)
+        onClick={(e) => e.stopPropagation()}
+      >
+        {/* ── Progress bar ─────────────────────────────────────────────── */}
+        <div style={{
+          height: 2, borderRadius: 2,
+          background: 'var(--card-border)',
+          marginBottom: 18,
+          overflow: 'hidden',
+        }}>
+          <div style={{
+            height: '100%', borderRadius: 2,
+            background: '#3385FF',
+            width: `${progress}%`,
+            transition: 'width 0.25s ease',
+          }} />
+        </div>
+
+        {/* ── Step counter ─────────────────────────────────────────────── */}
+        <div style={{
+          display: 'flex', alignItems: 'center', justifyContent: 'space-between',
+          marginBottom: 10,
+        }}>
+          <span style={{
+            fontSize: '0.6875rem', fontWeight: 600, letterSpacing: '0.06em',
+            textTransform: 'uppercase', color: '#3385FF',
+          }}>
+            Step {stepIndex + 1} of {TOUR_STEPS.length}
+          </span>
+          <button
+            onClick={dismiss}
+            aria-label="Close tour"
+            style={{
+              background: 'none', border: 'none', cursor: 'pointer',
+              color: 'var(--card-muted)', padding: '2px 4px',
+              display: 'flex', alignItems: 'center', borderRadius: 4,
+              lineHeight: 1,
+            }}
+          >
+            <svg width="12" height="12" viewBox="0 0 12 12" fill="none">
+              <path d="M1 1l10 10M11 1L1 11" stroke="currentColor" strokeWidth="1.5" strokeLinecap="round"/>
+            </svg>
+          </button>
+        </div>
+
+        {/* ── Title ────────────────────────────────────────────────────── */}
+        <h3 style={{
+          fontSize: '1rem', fontWeight: 700, letterSpacing: '-0.025em',
+          color: 'var(--card-text)', margin: '0 0 10px',
+        }}>
+          {step.title}
+        </h3>
+
+        {/* ── Body ─────────────────────────────────────────────────────── */}
+        <div style={{
+          fontSize: '0.8125rem', color: 'var(--card-muted)',
+          lineHeight: 1.65, margin: '0 0 14px',
+        }}>
+          {step.body}
+        </div>
+
+        {/* ── Path mismatch hint ───────────────────────────────────────── */}
+        {pathMismatch && step.requiredPathPart && (
+          <div style={{
+            padding: '8px 10px', borderRadius: 7, marginBottom: 14,
+            background: 'rgba(51,133,255,0.08)',
+            border: '1px solid rgba(51,133,255,0.2)',
+            fontSize: '0.75rem', color: 'var(--card-muted)', lineHeight: 1.5,
+          }}>
+            💡 Navigate to the{' '}
+            <strong style={{ color: 'var(--card-text)' }}>
+              {step.requiredPathPart.includes('/project/') ? 'canvas' : 'workspace dashboard'}
+            </strong>{' '}
+            to follow this step interactively.
+          </div>
+        )}
+
+        {/* ── CLI code block ───────────────────────────────────────────── */}
+        {step.codeBlock && (
+          <pre style={{
+            background: 'var(--card-subtle)',
+            border: '1px solid var(--card-border)',
+            borderRadius: 8, padding: '10px 12px',
+            fontSize: '0.6875rem', lineHeight: 1.7,
+            fontFamily: "'JetBrains Mono', 'SF Mono', ui-monospace, monospace",
+            color: 'var(--card-text)',
+            margin: '0 0 14px',
+            overflow: 'auto', whiteSpace: 'pre',
+          }}>
+            {step.codeBlock}
+          </pre>
+        )}
+
+        {/* ── Navigation ───────────────────────────────────────────────── */}
+        <div style={{ display: 'flex', gap: 8, alignItems: 'center', marginTop: 4 }}>
+          {/* Back button */}
+          {!isFirstStep && (
+            <button
+              onClick={prev}
+              style={{
+                padding: '8px 14px', borderRadius: 8,
+                border: '1px solid var(--card-border)',
+                background: 'var(--btn-idle-bg)',
+                color: 'var(--btn-idle-fg)',
+                fontSize: '0.8125rem', fontWeight: 500,
+                cursor: 'pointer', fontFamily: 'inherit',
+              }}
+            >
+              ← Back
+            </button>
+          )}
+
+          {/* Next / Finish button */}
+          <button
+            onClick={() => next(TOUR_STEPS.length)}
+            style={{
+              flex: 1,
+              padding: '9px 16px', borderRadius: 8,
+              border: 'none',
+              background: isLastStep ? '#10B981' : '#3385FF',
+              color: '#FFFFFF',
+              fontSize: '0.8125rem', fontWeight: 600,
+              cursor: 'pointer', fontFamily: 'inherit',
+              letterSpacing: '-0.01em',
+              transition: 'background 0.12s',
+            }}
+          >
+            {isFirstStep
+              ? "Let's go →"
+              : isLastStep
+                ? 'Start building ✓'
+                : 'Next →'}
+          </button>
+
+          {/* Skip tour */}
+          {!isLastStep && (
+            <button
+              onClick={dismiss}
+              style={{
+                padding: '8px 10px', background: 'none', border: 'none',
+                color: 'var(--card-muted)', fontSize: '0.75rem',
+                cursor: 'pointer', fontFamily: 'inherit',
+              }}
+            >
+              Skip
+            </button>
+          )}
+        </div>
+      </div>
+
+      {/* ── Spotlight arrow (pointer from tooltip toward the target) ────── */}
+      {spotlight && <SpotlightArrow spotlight={spotlight} tooltipStyle={tooltipStyle} />}
+    </>,
+    document.body,
+  );
+}
+
+// ── Spotlight arrow ───────────────────────────────────────────────────────────
+// A small triangle that connects the tooltip card to the spotlit element.
+
+function SpotlightArrow({
+  spotlight,
+  tooltipStyle,
+}: {
+  spotlight: Rect;
+  tooltipStyle: React.CSSProperties;
+}) {
+  // Determine rough position of tooltip relative to spotlight centre to pick
+  // the correct arrow direction.
+  const slCX = spotlight.x + spotlight.width  / 2;
+  const slCY = spotlight.y + spotlight.height / 2;
+
+  // Resolve tooltip top-left from the style object (may use numbers or strings)
+  const ttTop  = typeof tooltipStyle.top    === 'number' ? tooltipStyle.top    : 0;
+  const ttLeft = typeof tooltipStyle.left   === 'number' ? tooltipStyle.left   : 0;
+  const ttCX   = ttLeft + TOOLTIP_WIDTH / 2;
+
+  // Arrow placed on the edge of the spotlight nearest the tooltip.
+  const above = ttTop < slCY;  // tooltip is above spotlight
+
+  const arrowX = Math.min(
+    Math.max(ttCX, spotlight.x + 12),
+    spotlight.x + spotlight.width - 12,
+  );
+
+  if (above) {
+    // Arrow at bottom of tooltip (pointing down toward spotlight)
+    return (
+      <div aria-hidden="true" style={{
+        position: 'fixed',
+        left:    arrowX - 7,
+        top:     Number(ttTop) + /* tooltip est. height */ 260,
+        width: 14, height: 8,
+        zIndex: 9999,
+        pointerEvents: 'none',
+        overflow: 'hidden',
+      }}>
+        <div style={{
+          width: 14, height: 14,
+          background: 'var(--card-bg)',
+          border: '1px solid var(--card-border)',
+          transform: 'rotate(45deg) translateY(-7px)',
+        }} />
+      </div>
+    );
+  }
+
+  // Arrow at top of tooltip (pointing up toward spotlight — tooltip is below)
+  const arrowTop = typeof tooltipStyle.top === 'number' ? tooltipStyle.top - 8 : 0;
+  return (
+    <div aria-hidden="true" style={{
+      position: 'fixed',
+      left:    arrowX - 7,
+      top:     arrowTop,
+      width: 14, height: 8,
+      zIndex: 9999,
+      pointerEvents: 'none',
+      overflow: 'hidden',
+    }}>
+      <div style={{
+        width: 14, height: 14,
+        background: 'var(--card-bg)',
+        border: '1px solid var(--card-border)',
+        transform: 'rotate(45deg) translateY(1px)',
+      }} />
+    </div>
+  );
+}
+
+// ── Tooltip positioning ───────────────────────────────────────────────────────
+
+function computeTooltipPosition(
+  rect: Rect | null,
+  placement: TourStep['placement'],
+): React.CSSProperties {
+  const vw  = typeof window !== 'undefined' ? window.innerWidth  : 1280;
+  const vh  = typeof window !== 'undefined' ? window.innerHeight : 800;
+  const pad = 16;
+
+  if (!rect) {
+    // Centered card
+    return {
+      left: Math.max(pad, (vw - TOOLTIP_WIDTH) / 2),
+      top:  Math.max(pad, vh / 2 - 160),
+    };
+  }
+
+  const sl = {
+    x:      rect.x      - SPOTLIGHT_PAD,
+    y:      rect.y      - SPOTLIGHT_PAD,
+    width:  rect.width  + SPOTLIGHT_PAD * 2,
+    height: rect.height + SPOTLIGHT_PAD * 2,
+  };
+
+  // Clamp a horizontal position to stay within viewport.
+  const clampLeft = (l: number) =>
+    Math.max(pad, Math.min(vw - TOOLTIP_WIDTH - pad, l));
+
+  const centredLeft = clampLeft(sl.x + sl.width / 2 - TOOLTIP_WIDTH / 2);
+
+  const spaceBelow = vh - (sl.y + sl.height);
+  const spaceAbove = sl.y;
+  const spaceRight = vw - (sl.x + sl.width);
+  const spaceLeft  = sl.x;
+
+  const effectivePlacement = placement === 'auto' || !placement
+    ? spaceBelow >= 240 ? 'bottom'
+    : spaceAbove >= 240 ? 'top'
+    : spaceRight >= TOOLTIP_WIDTH + GAP ? 'right'
+    : spaceLeft  >= TOOLTIP_WIDTH + GAP ? 'left'
+    : 'bottom'
+    : placement;
+
+  switch (effectivePlacement) {
+    case 'bottom':
+      return { left: centredLeft, top: sl.y + sl.height + GAP };
+    case 'top':
+      return { left: centredLeft, top: Math.max(pad, sl.y - GAP - 280) };
+    case 'right':
+      return { left: sl.x + sl.width + GAP, top: Math.max(pad, sl.y) };
+    case 'left':
+      return { left: Math.max(pad, sl.x - TOOLTIP_WIDTH - GAP), top: Math.max(pad, sl.y) };
+    default:
+      return { left: centredLeft, top: sl.y + sl.height + GAP };
+  }
+}
+
+// Imported only for the type — avoids a circular import.
+import type { TourStep } from './tourSteps';
diff --git a/packages/app/src/components/walkthrough/tourSteps.tsx b/packages/app/src/components/walkthrough/tourSteps.tsx
new file mode 100644
index 0000000..662c6cf
--- /dev/null
+++ b/packages/app/src/components/walkthrough/tourSteps.tsx
@@ -0,0 +1,189 @@
+import type { ReactNode } from 'react';
+
+export interface TourStep {
+  /** Unique key — also used as aria-label. */
+  id: string;
+  title: string;
+  body: ReactNode;
+  /** Optional shell command shown in a monospace code block. */
+  codeBlock?: string;
+  /** CSS selector for the element to spotlight. Falls back to centered modal. */
+  targetSelector?: string;
+  /** Which side of the spotlight to place the tooltip.
+   *  'auto' (default): below if space available, otherwise above. */
+  placement?: 'top' | 'bottom' | 'left' | 'right' | 'auto';
+  /** URL substring — if present and current URL does NOT include it,
+   *  the spotlight is skipped and the card shows a navigation hint. */
+  requiredPathPart?: string;
+}
+
+// ── Tour steps ─────────────────────────────────────────────────────────────────
+// Steps walk the user from the workspace dashboard all the way through live
+// component inspection on the canvas. Descriptions are concise (< 3 sentences).
+
+export const TOUR_STEPS: TourStep[] = [
+  {
+    id: 'welcome',
+    title: 'Welcome to Originmain',
+    body: (
+      <>
+        Originmain gives you a live visual canvas for your running React apps —
+        inspect components, generate intent diffs, and ship changes with AI. Let&apos;s
+        get you set up in under 2 minutes.
+      </>
+    ),
+    // No target — renders as a centered welcome card.
+  },
+
+  {
+    id: 'workspace-projects',
+    title: 'Your workspace',
+    body: (
+      <>
+        This is your workspace. It holds all your projects, team members, and
+        design language files. Each project connects to a single running
+        application — local, staging, or preview.
+      </>
+    ),
+    targetSelector: '[data-tour="projects-section"]',
+    placement: 'bottom',
+    requiredPathPart: '/workspace/',
+  },
+
+  {
+    id: 'new-project',
+    title: 'Create a project',
+    body: (
+      <>
+        Click <strong>New project</strong> to create your first project.
+        You&apos;ll give it a name, an optional URL, and a framework — you can
+        always change these later in project settings.
+      </>
+    ),
+    targetSelector: '[data-tour="new-project-btn"]',
+    placement: 'bottom',
+    requiredPathPart: '/workspace/',
+  },
+
+  {
+    id: 'open-canvas',
+    title: 'Open the canvas',
+    body: (
+      <>
+        Click any project card to open its visual canvas editor. The canvas is
+        where live rendering, component inspection, diff generation, and AI
+        queries all live.
+      </>
+    ),
+    targetSelector: '[data-tour="project-card"]',
+    placement: 'bottom',
+    requiredPathPart: '/workspace/',
+  },
+
+  {
+    id: 'canvas-overview',
+    title: 'The canvas editor',
+    body: (
+      <>
+        Left panel: artboard navigator and file tree. Center: infinite canvas
+        with your artboards. Right: the inspector — props, diffs, and the live
+        component graph. Press <kbd style={{ fontFamily: 'inherit' }}>V</kbd>,{' '}
+        <kbd style={{ fontFamily: 'inherit' }}>H</kbd>,{' '}
+        <kbd style={{ fontFamily: 'inherit' }}>A</kbd> to switch tools.
+      </>
+    ),
+    // No target — full-canvas overview shown as a centered card.
+    requiredPathPart: '/project/',
+  },
+
+  {
+    id: 'connect-app',
+    title: 'Connect your app',
+    body: (
+      <>
+        Run the CLI proxy in a second terminal. It strips iframing headers and
+        injects the Originmain fiber hook into your dev server&apos;s HTML — zero
+        changes to your app code needed.
+      </>
+    ),
+    codeBlock: `# Terminal 2 — keep your dev server running in Terminal 1
+npx @originmain/cli dev --target http://localhost:3000
+
+# ✓ Proxy listening on http://localhost:4170
+# Paste http://localhost:4170 into the artboard URL input`,
+    targetSelector: '[data-tour="artboard-empty"]',
+    placement: 'right',
+    requiredPathPart: '/project/',
+  },
+
+  {
+    id: 'enter-url',
+    title: 'Enter the proxy URL',
+    body: (
+      <>
+        Click <strong>Enter proxy URL</strong>, paste{' '}
+        <code
+          style={{
+            fontFamily: "'JetBrains Mono', ui-monospace, monospace",
+            fontSize: '0.8em',
+            background: 'var(--card-subtle)',
+            padding: '1px 4px',
+            borderRadius: 3,
+          }}
+        >
+          http://localhost:4170
+        </code>
+        , and press Connect. The artboard will render your live app and begin
+        streaming the React fiber tree.
+      </>
+    ),
+    targetSelector: '[data-tour="artboard-url-btn"]',
+    placement: 'top',
+    requiredPathPart: '/project/',
+  },
+
+  {
+    id: 'navigator-live',
+    title: 'Live connection established',
+    body: (
+      <>
+        A pulsing green dot in the navigator means Originmain has an active
+        fiber connection. Every React commit — including HMR hot updates —
+        streams the full component tree to the canvas in real time.
+      </>
+    ),
+    targetSelector: '[data-tour="navigator-panel"]',
+    placement: 'right',
+    requiredPathPart: '/project/',
+  },
+
+  {
+    id: 'inspector',
+    title: 'Inspect any component',
+    body: (
+      <>
+        Click any element in the canvas to select it. The inspector shows its
+        live props, lets you export an intent diff, and gives you a full
+        component graph. The AI query bar runs cross-artboard analysis.
+      </>
+    ),
+    targetSelector: '[data-tour="inspector-panel"]',
+    placement: 'left',
+    requiredPathPart: '/project/',
+  },
+
+  {
+    id: 'done',
+    title: "You're all set 🎉",
+    body: (
+      <>
+        You know how to connect an app, inspect components, and navigate the
+        canvas. Explore the diff tab to generate intent diffs, or add more
+        artboards with{' '}
+        <kbd style={{ fontFamily: 'inherit' }}>A</kbd> and connect different
+        routes.
+      </>
+    ),
+    // Centered finish card — no spotlight.
+  },
+];
diff --git a/packages/app/src/store/walkthrough.ts b/packages/app/src/store/walkthrough.ts
new file mode 100644
index 0000000..9309414
--- /dev/null
+++ b/packages/app/src/store/walkthrough.ts
@@ -0,0 +1,48 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+interface WalkthroughStore {
+  /** Whether the tour overlay is currently visible. */
+  active: boolean;
+  /** Zero-based index of the current step. */
+  stepIndex: number;
+  /** True once the user reaches the final step and closes the tour. */
+  completed: boolean;
+  start: () => void;
+  next: (totalSteps: number) => void;
+  prev: () => void;
+  dismiss: () => void;
+  restart: () => void;
+}
+
+export const useWalkthrough = create<WalkthroughStore>()(
+  persist(
+    (set) => ({
+      active:    false,
+      stepIndex: 0,
+      completed: false,
+
+      start: () => set({ active: true, stepIndex: 0 }),
+
+      next: (totalSteps: number) =>
+        set((s) => {
+          const next = s.stepIndex + 1;
+          if (next >= totalSteps) {
+            // Reached the end — mark complete and close.
+            return { active: false, completed: true, stepIndex: 0 };
+          }
+          return { stepIndex: next };
+        }),
+
+      prev: () =>
+        set((s) => ({ stepIndex: Math.max(0, s.stepIndex - 1) })),
+
+      dismiss: () => set({ active: false }),
+
+      restart: () => set({ active: true, stepIndex: 0, completed: false }),
+    }),
+    {
+      name: 'originmain:tour',
+    },
+  ),
+);
diff --git a/packages/live-sdk/src/hook.ts b/packages/live-sdk/src/hook.ts
index e623046..e8a062b 100644
--- a/packages/live-sdk/src/hook.ts
+++ b/packages/live-sdk/src/hook.ts
@@ -1,28 +1,37 @@
-// ── Originmain Fiber Hook ────────────────────────────────────────────────────
-// This module installs a React DevTools–compatible global hook BEFORE React
-// evaluates its module body. React checks for __REACT_DEVTOOLS_GLOBAL_HOOK__
-// exactly once at import time; any later installation is too late.
+// ── Originmain Fiber Hook (Live SDK) ─────────────────────────────────────────
+// Installs a React DevTools–compatible global hook BEFORE React evaluates its
+// module body. React checks for __REACT_DEVTOOLS_GLOBAL_HOOK__ exactly once at
+// import time; any later installation is too late.
 //
-// The hook only activates when the app is iframed by Originmain (detected by
-// the `om:` prefix in `window.name`, which LiveArtboard.tsx sets on the
-// <iframe> element). Outside an Originmain iframe the module is a no-op.
+// Full bidirectional protocol:
+//   Renderer → Host : READY, FIBER_TREE_UPDATE, COMPONENT_SELECTED, ERROR
+//   Host → Renderer : SET_DESIGN_TOKENS, NAVIGATE, SELECT_COMPONENT, DESELECT
 //
-// This file is intentionally self-contained — no imports from other
-// @originmain/* packages — because it ships as a public npm package.
+// Node IDs are stable path strings: "Component:idx/Child:idx/…"
+// This survives re-renders as long as the component tree structure is unchanged.
+//
+// Guard: only activates when window.name starts with "om:" — the prefix set by
+// LiveArtboard.tsx on the <iframe name="om:{id}"> element. Outside Originmain
+// iframes this module is a complete no-op.
+//
+// This file is intentionally self-contained (no @originmain/* imports) because
+// it ships as a public npm package and must work standalone.
 
 const RENDERER_SOURCE = 'originmain-renderer';
-const NAME_PREFIX = 'om:';
+const HOST_SOURCE     = 'originmain-host';
+const NAME_PREFIX     = 'om:';
 
-// ── Guard: only run inside an Originmain iframe ──────────────────────────────
+// ── Guard ─────────────────────────────────────────────────────────────────────
 
 function isOriginmainIframe(): boolean {
   try {
-    return window.parent !== window
-      && typeof window.name === 'string'
-      && window.name.startsWith(NAME_PREFIX);
+    return (
+      window.parent !== window &&
+      typeof window.name === 'string' &&
+      window.name.startsWith(NAME_PREFIX)
+    );
   } catch {
-    // Accessing window.parent can throw in certain sandboxed contexts.
-    return false;
+    return false; // Accessing window.parent can throw in certain sandboxed contexts.
   }
 }
 
@@ -30,11 +39,12 @@ if (isOriginmainIframe()) {
   installFiberHook();
 }
 
-// ── Core ─────────────────────────────────────────────────────────────────────
+// ── Core ──────────────────────────────────────────────────────────────────────
 
 function installFiberHook(): void {
   const artboardId = window.name.slice(NAME_PREFIX.length);
 
+  // ── postMessage helper ────────────────────────────────────────────────────
   function post(msg: Record<string, unknown>): void {
     try {
       window.parent.postMessage(
@@ -46,8 +56,13 @@ function installFiberHook(): void {
     }
   }
 
-  // Install or wrap the global hook. If React DevTools is already present,
-  // we wrap its onCommitFiberRoot so both receive commits.
+  // ── Runtime state ─────────────────────────────────────────────────────────
+  let currentTree: SerializedNode | null = null;
+  const nodeMap = new Map<string, { domRect: DomRect | null }>();
+  let selectedNodeId: string | null = null;
+  let highlightEl: HTMLElement | null = null;
+
+  // ── React DevTools global hook ─────────────────────────────────────────────
   type Hook = {
     renderers: Map<unknown, unknown>;
     supportsFiber: boolean;
@@ -64,31 +79,248 @@ function installFiberHook(): void {
     g.__REACT_DEVTOOLS_GLOBAL_HOOK__ = hook;
   }
 
-  const originalOnCommit = hook.onCommitFiberRoot;
+  const _prevCommit = hook.onCommitFiberRoot;
 
   hook.onCommitFiberRoot = function onCommitFiberRoot(...args: unknown[]) {
-    // Delegate to the previous handler (React DevTools) first.
-    if (typeof originalOnCommit === 'function') {
-      try { originalOnCommit.apply(this, args); }
-      catch { /* don't break DevTools */ }
+    // Delegate to any pre-existing handler (React DevTools extension) first.
+    if (typeof _prevCommit === 'function') {
+      try { _prevCommit.apply(this, args); }
+      catch { /* don't break existing DevTools */ }
     }
 
     try {
-      // args[1] is the FiberRoot — { current: Fiber }
+      // args[1] is the FiberRoot object — { current: Fiber }
       const root = args[1] as { current: FiberLike } | undefined;
       if (!root?.current) return;
-      const tree = serializeFiber(root.current);
+
+      const tree = serializeFiber(root.current, '');
+      currentTree = tree;
+      rebuildNodeMap(tree);
       post({ type: 'FIBER_TREE_UPDATE', root: tree });
+      // Re-sync the highlight ring after each React commit (component may move).
+      if (selectedNodeId) updateHighlight();
     } catch (err) {
       post({ type: 'ERROR', message: String(err) });
     }
   };
 
-  // Signal readiness.
+  // ── Fiber serialization (stable path-based IDs) ───────────────────────────
+
+  function serializeFiber(
+    fiber: FiberLike | null,
+    parentId: string,
+  ): SerializedNode | null {
+    if (!fiber) return null;
+
+    const name = getDisplayName(fiber);
+    if (!name) {
+      // Unnamed fiber — skip level but keep walking children.
+      let child = fiber.child;
+      while (child) {
+        const s = serializeFiber(child, parentId);
+        if (s) return s;
+        child = child.sibling;
+      }
+      return null;
+    }
+
+    const nodeId = (parentId ? parentId + '/' : '') + name + ':' + String(fiber.index);
+    const rect   = getDomRect(fiber);
+    const node: SerializedNode = {
+      id:       nodeId,
+      name,
+      props:    serializeProps(fiber.memoizedProps),
+      children: [],
+    };
+    if (rect) node.domRect = rect;
+
+    let child = fiber.child;
+    while (child) {
+      const serialized = serializeFiber(child, nodeId);
+      if (serialized) node.children.push(serialized);
+      child = child.sibling;
+    }
+    return node;
+  }
+
+  function getDisplayName(fiber: FiberLike): string | null {
+    const type = fiber.type;
+    if (!type) return null;
+    if (typeof type === 'string') return type;
+    if (typeof type === 'function') {
+      return (type as { displayName?: string; name?: string }).displayName
+        ?? (type as { name?: string }).name
+        ?? null;
+    }
+    if (typeof type === 'object' && type !== null && '$$typeof' in type) {
+      return (type as { displayName?: string; name?: string }).displayName
+        ?? (type as { name?: string }).name
+        ?? null;
+    }
+    return null;
+  }
+
+  function getDomRect(fiber: FiberLike): DomRect | null {
+    try {
+      const dom = fiber.stateNode;
+      if (dom && typeof dom === 'object' && 'getBoundingClientRect' in dom) {
+        const r = (dom as Element).getBoundingClientRect();
+        return { x: r.x, y: r.y, width: r.width, height: r.height };
+      }
+    } catch { /* stateNode has no layout */ }
+    return null;
+  }
+
+  function serializeProps(
+    props: Record<string, unknown> | null,
+  ): Record<string, string | number | boolean | null> {
+    if (!props || typeof props !== 'object') return {};
+    const out: Record<string, string | number | boolean | null> = {};
+    for (const key in props) {
+      if (key === 'children') continue;
+      const val = props[key];
+      const t = typeof val;
+      if (t === 'string' || t === 'number' || t === 'boolean' || val === null) {
+        out[key] = val as string | number | boolean | null;
+      }
+    }
+    return out;
+  }
+
+  // ── Node map: flat O(1) lookup by stable ID ───────────────────────────────
+
+  function rebuildNodeMap(node: SerializedNode | null): void {
+    nodeMap.clear();
+    fillMap(node);
+  }
+
+  function fillMap(node: SerializedNode | null): void {
+    if (!node) return;
+    nodeMap.set(node.id, { domRect: node.domRect ?? null });
+    for (const child of node.children) fillMap(child);
+  }
+
+  // ── Highlight overlay (blue ring inside the iframe) ───────────────────────
+
+  function updateHighlight(): void {
+    const info = selectedNodeId ? nodeMap.get(selectedNodeId) : undefined;
+    if (info?.domRect) renderHighlight(info.domRect);
+    else removeHighlight();
+  }
+
+  function renderHighlight(rect: DomRect): void {
+    if (!highlightEl) {
+      highlightEl = document.createElement('div');
+      highlightEl.id = '__om_sel__';
+      highlightEl.setAttribute('aria-hidden', 'true');
+      highlightEl.style.cssText = [
+        'position:fixed', 'pointer-events:none', 'z-index:2147483647',
+        'box-shadow:0 0 0 2px #3385FF',
+        'outline:3px solid rgba(51,133,255,0.18)',
+        'border-radius:3px',
+        'transition:left .07s ease,top .07s ease,width .07s ease,height .07s ease',
+      ].join(';');
+      document.body.appendChild(highlightEl);
+    }
+    highlightEl.style.left   = `${rect.x}px`;
+    highlightEl.style.top    = `${rect.y}px`;
+    highlightEl.style.width  = `${rect.width}px`;
+    highlightEl.style.height = `${rect.height}px`;
+  }
+
+  function removeHighlight(): void {
+    if (highlightEl?.parentNode) {
+      highlightEl.parentNode.removeChild(highlightEl);
+      highlightEl = null;
+    }
+  }
+
+  // ── Click-to-select (capturing phase) ────────────────────────────────────
+
+  document.addEventListener('click', (event: MouseEvent) => {
+    const node = findDeepestAt(currentTree, event.clientX, event.clientY);
+    if (node?.domRect) {
+      post({ type: 'COMPONENT_SELECTED', nodeId: node.id, rect: node.domRect });
+    }
+  }, true);
+
+  function findDeepestAt(
+    node: SerializedNode | null,
+    x: number,
+    y: number,
+  ): SerializedNode | null {
+    if (!node) return null;
+    const r   = node.domRect;
+    const hit = r && x >= r.x && x <= r.x + r.width && y >= r.y && y <= r.y + r.height;
+
+    if (hit) {
+      for (const child of node.children) {
+        const deeper = findDeepestAt(child, x, y);
+        if (deeper) return deeper;
+      }
+      return node;
+    }
+
+    // No hit — still check children for overflow:visible scenarios.
+    for (const child of node.children) {
+      const found = findDeepestAt(child, x, y);
+      if (found) return found;
+    }
+    return null;
+  }
+
+  // ── Host → Renderer message handler ──────────────────────────────────────
+
+  window.addEventListener('message', (event: MessageEvent) => {
+    const data = event.data as {
+      source?: string;
+      artboardId?: string;
+      message?: { type: string; tokens?: Record<string, string>; path?: string; nodeId?: string };
+    };
+    if (!data || data.source !== HOST_SOURCE)    return;
+    if (data.artboardId !== artboardId)          return;
+    const msg = data.message;
+    if (!msg) return;
+
+    switch (msg.type) {
+      case 'SET_DESIGN_TOKENS':
+        if (msg.tokens) applyTokens(msg.tokens);
+        break;
+      case 'NAVIGATE':
+        if (msg.path) doNavigate(msg.path);
+        break;
+      case 'SELECT_COMPONENT':
+        if (msg.nodeId) {
+          selectedNodeId = msg.nodeId;
+          updateHighlight();
+        }
+        break;
+      case 'DESELECT':
+        selectedNodeId = null;
+        removeHighlight();
+        break;
+    }
+  });
+
+  function applyTokens(tokens: Record<string, string>): void {
+    const root = document.documentElement;
+    for (const [k, v] of Object.entries(tokens)) {
+      root.style.setProperty(k, v);
+    }
+  }
+
+  function doNavigate(path: string): void {
+    try {
+      history.pushState(null, '', path);
+      window.dispatchEvent(new PopStateEvent('popstate', { state: null }));
+    } catch { /* navigation not available */ }
+  }
+
+  // ── Ready signal ──────────────────────────────────────────────────────────
   post({ type: 'READY' });
 }
 
-// ── Fiber Serialization ──────────────────────────────────────────────────────
+// ── Internal types ────────────────────────────────────────────────────────────
 
 interface FiberLike {
   type: unknown;
@@ -99,80 +331,17 @@ interface FiberLike {
   memoizedProps: Record<string, unknown> | null;
 }
 
+interface DomRect {
+  x: number;
+  y: number;
+  width: number;
+  height: number;
+}
+
 interface SerializedNode {
-  id: string;
-  name: string;
-  props: Record<string, string | number | boolean | null>;
+  id:       string;
+  name:     string;
+  props:    Record<string, string | number | boolean | null>;
   children: SerializedNode[];
-  domRect?: { x: number; y: number; width: number; height: number };
-}
-
-function serializeFiber(fiber: FiberLike | null): SerializedNode | null {
-  if (!fiber) return null;
-
-  const name = getDisplayName(fiber);
-  if (!name) return serializeFiber(fiber.child);
-
-  const rect = getDomRect(fiber);
-  const node: SerializedNode = {
-    id: String(fiber.index || Math.random()),
-    name,
-    props: serializeProps(fiber.memoizedProps),
-    children: [],
-  };
-  if (rect) {
-    node.domRect = rect;
-  }
-
-  let child = fiber.child;
-  while (child) {
-    const serialized = serializeFiber(child);
-    if (serialized) node.children.push(serialized);
-    child = child.sibling;
-  }
-  return node;
-}
-
-function getDisplayName(fiber: FiberLike): string | null {
-  const type = fiber.type;
-  if (!type) return null;
-  if (typeof type === 'string') return type;
-  if (typeof type === 'function') {
-    return (type as { displayName?: string; name?: string }).displayName
-      ?? (type as { name?: string }).name
-      ?? null;
-  }
-  if (typeof type === 'object' && type !== null && '$$typeof' in type) {
-    return (type as { displayName?: string; name?: string }).displayName
-      ?? (type as { name?: string }).name
-      ?? null;
-  }
-  return null;
-}
-
-function getDomRect(fiber: FiberLike): { x: number; y: number; width: number; height: number } | null {
-  try {
-    const dom = fiber.stateNode;
-    if (dom && typeof dom === 'object' && 'getBoundingClientRect' in dom) {
-      const r = (dom as Element).getBoundingClientRect();
-      return { x: r.x, y: r.y, width: r.width, height: r.height };
-    }
-  } catch { /* no DOM node */ }
-  return null;
-}
-
-function serializeProps(
-  props: Record<string, unknown> | null,
-): Record<string, string | number | boolean | null> {
-  if (!props || typeof props !== 'object') return {};
-  const out: Record<string, string | number | boolean | null> = {};
-  for (const key in props) {
-    if (key === 'children') continue;
-    const val = props[key];
-    const t = typeof val;
-    if (t === 'string' || t === 'number' || t === 'boolean' || val === null) {
-      out[key] = val as string | number | boolean | null;
-    }
-  }
-  return out;
+  domRect?: DomRect;
 }
diff --git a/packages/renderer/src/fiber-hook.ts b/packages/renderer/src/fiber-hook.ts
index f9f0d48..37cb417 100644
--- a/packages/renderer/src/fiber-hook.ts
+++ b/packages/renderer/src/fiber-hook.ts
@@ -1,23 +1,15 @@
-import { RENDERER_SOURCE } from './protocol.js';
+import { RENDERER_SOURCE, HOST_SOURCE } from './protocol.js';
 import type { FiberNode, DOMRectLike } from './protocol.js';
 
-// ── Fiber hook script ─────────────────────────────────────────────────────────
-// This script is injected into the sandboxed iframe before the remote app
-// initialises. It installs a React DevTools global hook so React reports every
-// commit. On each commit, we walk the Fiber tree, serialize it to FiberNode[],
-// and postMessage the result to the host.
-//
-// The script must be self-contained (no imports) because it runs in the iframe.
-// We generate it as a string via buildFiberHookScript() so it can be injected
-// via a <script> tag or a blob URL.
+// ── Legacy fiber hook script ──────────────────────────────────────────────────
+// @deprecated Use buildProxyFiberHookScript() instead. This version bakes
+// the artboard ID into the script at generation time; the proxy-compatible
+// version reads it from window.name at runtime.
 
 export function buildFiberHookScript(artboardId: string): string {
-  // Inline the constants and logic — the iframe has no access to this module.
   return `(function(artboardId) {
   var SOURCE = ${JSON.stringify(RENDERER_SOURCE)};
 
-  // Install the React DevTools global hook BEFORE React loads.
-  // React checks for this object at module evaluation time and registers itself.
   var hook = window.__REACT_DEVTOOLS_GLOBAL_HOOK__;
   if (!hook) {
     hook = { renderers: new Map(), _isDisabled: false };
@@ -102,7 +94,6 @@ export function buildFiberHookScript(artboardId: string): string {
     return out;
   }
 
-  // Signal that the renderer iframe is ready.
   window.parent.postMessage(
     { source: SOURCE, artboardId: artboardId, message: { type: 'READY' } },
     '*'
@@ -111,76 +102,108 @@ export function buildFiberHookScript(artboardId: string): string {
 }
 
 // ── Proxy-compatible fiber hook script ────────────────────────────────────────
-// Unlike buildFiberHookScript (which bakes in an artboard ID), this version
-// reads the artboard ID from `window.name` at runtime. The iframe element sets
-// `name="om:<artboardId>"` and this script extracts the ID.
+// Reads the artboard ID from window.name at runtime (set by LiveArtboard:
+// <iframe name="om:{id}">). Supports full bidirectional protocol:
 //
-// This script is injected by the CLI proxy (`@originmain/cli`) into every HTML
-// response, and is also used by the `@originmain/live` SDK. It is fully
-// self-contained — no imports, no dependencies.
+//   Renderer → Host : READY, FIBER_TREE_UPDATE, COMPONENT_SELECTED, ERROR
+//   Host → Renderer : SET_DESIGN_TOKENS, NAVIGATE, SELECT_COMPONENT, DESELECT
+//
+// Node IDs are stable path strings: "Component:idx/Child:idx/…"
+// This survives re-renders as long as tree structure is unchanged.
+//
+// Used by @originmain/cli (proxy injection) and @originmain/live (SDK).
 
 export function buildProxyFiberHookScript(): string {
   return `(function() {
-  // Only activate inside an Originmain iframe
+  'use strict';
+
+  // ── Guard: only activate inside an Originmain iframe ─────────────────────
   if (window.parent === window) return;
 
   var NAME_PREFIX = 'om:';
-  var artboardId = '';
+  var artboardId  = '';
   try {
     if (typeof window.name === 'string' && window.name.indexOf(NAME_PREFIX) === 0) {
       artboardId = window.name.slice(NAME_PREFIX.length);
     }
-  } catch (e) { /* window.name access denied — not our iframe */ }
+  } catch (e) { /* sandboxed context — not our iframe */ }
   if (!artboardId) return;
 
-  var SOURCE = ${JSON.stringify(RENDERER_SOURCE)};
+  var RENDERER_SOURCE = ${JSON.stringify(RENDERER_SOURCE)};
+  var HOST_SOURCE     = ${JSON.stringify(HOST_SOURCE)};
 
+  // ── Runtime state ─────────────────────────────────────────────────────────
+  var currentTree    = null;   // latest serialized FiberNode tree
+  var nodeMap        = {};     // nodeId → { domRect }  (flat for O(1) lookup)
+  var selectedNodeId = null;   // currently highlighted component
+  var highlightEl    = null;   // the blue-ring DOM overlay element
+
+  // ── postMessage helper ────────────────────────────────────────────────────
   function post(msg) {
-    try { window.parent.postMessage({ source: SOURCE, artboardId: artboardId, message: msg }, '*'); }
-    catch (e) { /* parent unreachable */ }
+    try {
+      window.parent.postMessage(
+        { source: RENDERER_SOURCE, artboardId: artboardId, message: msg }, '*'
+      );
+    } catch (e) { /* parent unreachable — swallow silently */ }
   }
 
-  // Install the React DevTools global hook BEFORE React loads.
-  // If React DevTools extension is already present, wrap its handler.
+  // ── React DevTools global hook ────────────────────────────────────────────
+  // Must be installed before React evaluates its module body. React checks for
+  // __REACT_DEVTOOLS_GLOBAL_HOOK__ exactly once at import time.
   var hook = window.__REACT_DEVTOOLS_GLOBAL_HOOK__;
   if (!hook) {
     hook = { renderers: new Map(), supportsFiber: true, _isDisabled: false };
     window.__REACT_DEVTOOLS_GLOBAL_HOOK__ = hook;
   }
 
-  var originalOnCommit = hook.onCommitFiberRoot;
+  var _prevCommit = hook.onCommitFiberRoot;
 
   hook.onCommitFiberRoot = function(rendererId, root, priorityLevel, didError) {
-    if (typeof originalOnCommit === 'function') {
-      try { originalOnCommit.call(this, rendererId, root, priorityLevel, didError); }
-      catch (e) { /* don't break DevTools */ }
+    // Delegate to any pre-existing handler (e.g. React DevTools extension).
+    if (typeof _prevCommit === 'function') {
+      try { _prevCommit.call(this, rendererId, root, priorityLevel, didError); }
+      catch (e) { /* don't break existing DevTools */ }
     }
     try {
-      var fiberRoot = root.current;
-      var tree = serializeFiber(fiberRoot);
+      var tree = serializeFiber(root.current, '');
+      currentTree = tree;
+      rebuildNodeMap(tree);
       post({ type: 'FIBER_TREE_UPDATE', root: tree });
+      // Re-sync the highlight ring after each React commit (position may shift).
+      if (selectedNodeId) updateHighlight();
     } catch (err) {
       post({ type: 'ERROR', message: String(err) });
     }
   };
 
-  function serializeFiber(fiber) {
+  // ── Fiber serialization (stable path-based IDs) ───────────────────────────
+  // ID format: "ComponentName:siblingIndex/ChildName:siblingIndex/..."
+  // Stable across re-renders provided the tree structure doesn't change.
+
+  function serializeFiber(fiber, parentId) {
     if (!fiber) return null;
     var name = getDisplayName(fiber);
-    if (!name) return serializeFiber(fiber.child) || null;
 
-    var rect = getDomRect(fiber);
-    var node = {
-      id: String(fiber.index || Math.random()),
-      name: name,
-      props: serializeProps(fiber.memoizedProps),
-      children: [],
-    };
+    if (!name) {
+      // Unnamed fiber (Fragment, Context, Provider) — skip this level,
+      // but keep walking children so named descendants are not lost.
+      var c = fiber.child;
+      while (c) {
+        var s = serializeFiber(c, parentId);
+        if (s) return s;
+        c = c.sibling;
+      }
+      return null;
+    }
+
+    var nodeId = (parentId ? parentId + '/' : '') + name + ':' + String(fiber.index);
+    var rect   = getDomRect(fiber);
+    var node   = { id: nodeId, name: name, props: serializeProps(fiber.memoizedProps), children: [] };
     if (rect) node.domRect = rect;
 
     var child = fiber.child;
     while (child) {
-      var serialized = serializeFiber(child);
+      var serialized = serializeFiber(child, nodeId);
       if (serialized) node.children.push(serialized);
       child = child.sibling;
     }
@@ -192,7 +215,7 @@ export function buildProxyFiberHookScript(): string {
     if (!type) return null;
     if (typeof type === 'string') return type;
     if (typeof type === 'function') return type.displayName || type.name || null;
-    if (type.$$typeof) return type.displayName || type.name || null;
+    if (type && type.$$typeof) return type.displayName || type.name || null;
     return null;
   }
 
@@ -203,7 +226,7 @@ export function buildProxyFiberHookScript(): string {
         var r = dom.getBoundingClientRect();
         return { x: r.x, y: r.y, width: r.width, height: r.height };
       }
-    } catch (e) { /* no DOM node */ }
+    } catch (e) { /* stateNode has no layout (Context, Memo, etc.) */ }
     return null;
   }
 
@@ -214,14 +237,144 @@ export function buildProxyFiberHookScript(): string {
       if (key === 'children') continue;
       var val = props[key];
       var t = typeof val;
-      if (t === 'string' || t === 'number' || t === 'boolean' || val === null) {
-        out[key] = val;
-      }
+      if (t === 'string' || t === 'number' || t === 'boolean' || val === null) out[key] = val;
     }
     return out;
   }
 
-  // Signal that the fiber hook is installed and the iframe is ready.
+  // ── Node map: flat O(1) lookup by stable ID ───────────────────────────────
+  function rebuildNodeMap(node) {
+    nodeMap = {};
+    fillMap(node);
+  }
+  function fillMap(node) {
+    if (!node) return;
+    nodeMap[node.id] = { domRect: node.domRect || null };
+    var children = node.children;
+    for (var i = 0; i < children.length; i++) fillMap(children[i]);
+  }
+
+  // ── Highlight overlay (blue ring inside the iframe) ───────────────────────
+  function updateHighlight() {
+    var info = nodeMap[selectedNodeId];
+    if (info && info.domRect) renderHighlight(info.domRect);
+    else removeHighlight();
+  }
+
+  function renderHighlight(rect) {
+    if (!highlightEl) {
+      highlightEl = document.createElement('div');
+      highlightEl.id = '__om_sel__';
+      highlightEl.setAttribute('aria-hidden', 'true');
+      // CSS kept inline so no stylesheet dependency. Transition animates when
+      // the selected component moves (e.g. during a re-render or scroll).
+      highlightEl.style.cssText = [
+        'position:fixed', 'pointer-events:none', 'z-index:2147483647',
+        'box-shadow:0 0 0 2px #3385FF',
+        'outline:3px solid rgba(51,133,255,0.18)',
+        'border-radius:3px',
+        'transition:left .07s ease,top .07s ease,width .07s ease,height .07s ease',
+      ].join(';');
+      document.body.appendChild(highlightEl);
+    }
+    highlightEl.style.left   = rect.x + 'px';
+    highlightEl.style.top    = rect.y + 'px';
+    highlightEl.style.width  = rect.width + 'px';
+    highlightEl.style.height = rect.height + 'px';
+  }
+
+  function removeHighlight() {
+    if (highlightEl && highlightEl.parentNode) {
+      highlightEl.parentNode.removeChild(highlightEl);
+      highlightEl = null;
+    }
+  }
+
+  // ── Click-to-select (capturing phase) ────────────────────────────────────
+  // Finds the deepest named fiber node at the click point and reports it back.
+  // In normal canvas usage the SelectionOverlay sits on top of the iframe and
+  // this listener fires when the overlay is bypassed (e.g. direct preview mode).
+
+  document.addEventListener('click', function(event) {
+    var node = findDeepestAt(currentTree, event.clientX, event.clientY);
+    if (node && node.domRect) {
+      post({ type: 'COMPONENT_SELECTED', nodeId: node.id, rect: node.domRect });
+    }
+  }, true);
+
+  function findDeepestAt(node, x, y) {
+    if (!node) return null;
+    var r   = node.domRect;
+    var hit = r && x >= r.x && x <= r.x + r.width && y >= r.y && y <= r.y + r.height;
+
+    if (hit) {
+      // Matched — recurse children for a deeper (more specific) match.
+      var children = node.children;
+      for (var i = 0; i < children.length; i++) {
+        var deeper = findDeepestAt(children[i], x, y);
+        if (deeper) return deeper;
+      }
+      return node;
+    }
+
+    // No hit on this node — still check children for overflow:visible cases.
+    var children = node.children;
+    for (var i = 0; i < children.length; i++) {
+      var found = findDeepestAt(children[i], x, y);
+      if (found) return found;
+    }
+    return null;
+  }
+
+  // ── Host → Renderer message handler ──────────────────────────────────────
+  window.addEventListener('message', function(event) {
+    var data = event.data;
+    if (!data || typeof data !== 'object') return;
+    if (data.source !== HOST_SOURCE)    return;
+    if (data.artboardId !== artboardId) return;
+    var msg = data.message;
+    if (!msg) return;
+
+    switch (msg.type) {
+      case 'SET_DESIGN_TOKENS':
+        if (msg.tokens && typeof msg.tokens === 'object') applyTokens(msg.tokens);
+        break;
+      case 'NAVIGATE':
+        if (typeof msg.path === 'string') doNavigate(msg.path);
+        break;
+      case 'SELECT_COMPONENT':
+        if (typeof msg.nodeId === 'string') {
+          selectedNodeId = msg.nodeId;
+          updateHighlight();
+        }
+        break;
+      case 'DESELECT':
+        selectedNodeId = null;
+        removeHighlight();
+        break;
+    }
+  });
+
+  // Apply DLF design tokens as CSS custom properties on :root.
+  function applyTokens(tokens) {
+    var root = document.documentElement;
+    for (var k in tokens) {
+      if (Object.prototype.hasOwnProperty.call(tokens, k)) {
+        root.style.setProperty(k, String(tokens[k]));
+      }
+    }
+  }
+
+  // SPA-safe navigation: push to history and fire popstate so framework
+  // routers (React Router, Next.js) pick up the route change.
+  function doNavigate(path) {
+    try {
+      history.pushState(null, '', path);
+      window.dispatchEvent(new PopStateEvent('popstate', { state: null }));
+    } catch (e) { /* navigation not available in this context */ }
+  }
+
+  // ── Ready signal ──────────────────────────────────────────────────────────
   post({ type: 'READY' });
 })();`;
 }