diff --git a/extension/background.js b/extension/background.js
index 6b5b08b7..e17834db 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -3,10 +3,13 @@
  *
  * Polls /health every 10s to detect browse server.
  * Fetches /refs on snapshot completion, relays to content script.
- * Updates badge: green (connected), gray (disconnected).
+ * Proxies commands from sidebar → browse server.
+ * Updates badge: amber (connected), gray (disconnected).
  */
 
+const DEFAULT_PORT = 34567;  // Well-known port used by `$B connect`
 let serverPort = null;
+let authToken = null;
 let isConnected = false;
 let healthInterval = null;
 
@@ -14,7 +17,7 @@ let healthInterval = null;
 
 async function loadPort() {
   const data = await chrome.storage.local.get('port');
-  serverPort = data.port || null;
+  serverPort = data.port || DEFAULT_PORT;
   return serverPort;
 }
 
@@ -41,6 +44,8 @@ async function checkHealth() {
     if (!resp.ok) { setDisconnected(); return; }
     const data = await resp.json();
     if (data.status === 'healthy') {
+      // Capture auth token from health response
+      if (data.token) authToken = data.token;
       setConnected(data);
     } else {
       setDisconnected();
@@ -53,7 +58,7 @@ async function checkHealth() {
 function setConnected(healthData) {
   const wasDisconnected = !isConnected;
   isConnected = true;
-  chrome.action.setBadgeBackgroundColor({ color: '#4ade80' });
+  chrome.action.setBadgeBackgroundColor({ color: '#F59E0B' });
   chrome.action.setBadgeText({ text: ' ' });
 
   // Broadcast health to popup and side panel
@@ -68,6 +73,7 @@ function setConnected(healthData) {
 function setDisconnected() {
   const wasConnected = isConnected;
   isConnected = false;
+  authToken = null;
   chrome.action.setBadgeText({ text: '' });
 
   chrome.runtime.sendMessage({ type: 'health', data: null }).catch(() => {});
@@ -89,6 +95,31 @@ async function notifyContentScripts(type) {
   } catch {}
 }
 
+// ─── Command Proxy ─────────────────────────────────────────────
+
+async function executeCommand(command, args) {
+  const base = getBaseUrl();
+  if (!base || !authToken) {
+    return { error: 'Not connected to browse server' };
+  }
+
+  try {
+    const resp = await fetch(`${base}/command`, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'Authorization': `Bearer ${authToken}`,
+      },
+      body: JSON.stringify({ command, args }),
+      signal: AbortSignal.timeout(30000),
+    });
+    const data = await resp.json();
+    return data;
+  } catch (err) {
+    return { error: err.message || 'Command failed' };
+  }
+}
+
 // ─── Refs Relay ─────────────────────────────────────────────────
 
 async function fetchAndRelayRefs() {
@@ -135,11 +166,41 @@ chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
     fetchAndRelayRefs().then(() => sendResponse({ ok: true }));
     return true;
   }
+
+  // Sidebar → browse server command proxy
+  if (msg.type === 'command') {
+    executeCommand(msg.command, msg.args).then(result => sendResponse(result));
+    return true;
+  }
+
+  // Sidebar → Claude Code (file-based message queue)
+  if (msg.type === 'sidebar-command') {
+    const base = getBaseUrl();
+    if (!base || !authToken) {
+      sendResponse({ error: 'Not connected' });
+      return true;
+    }
+    fetch(`${base}/sidebar-command`, {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        'Authorization': `Bearer ${authToken}`,
+      },
+      body: JSON.stringify({ message: msg.message }),
+    })
+      .then(r => r.json())
+      .then(data => sendResponse(data))
+      .catch(err => sendResponse({ error: err.message }));
+    return true;
+  }
 });
 
 // ─── Side Panel ─────────────────────────────────────────────────
 
-chrome.sidePanel.setPanelBehavior({ openPanelOnActionClick: false }).catch(() => {});
+// Click extension icon → open side panel directly (no popup)
+if (chrome.sidePanel && chrome.sidePanel.setPanelBehavior) {
+  chrome.sidePanel.setPanelBehavior({ openPanelOnActionClick: true }).catch(() => {});
+}
 
 // ─── Startup ────────────────────────────────────────────────────
 
diff --git a/extension/manifest.json b/extension/manifest.json
index 3a28d5ed..ea710e14 100644
--- a/extension/manifest.json
+++ b/extension/manifest.json
@@ -6,7 +6,6 @@
   "permissions": ["sidePanel", "storage", "activeTab"],
   "host_permissions": ["http://127.0.0.1:*/"],
   "action": {
-    "default_popup": "popup.html",
     "default_icon": {
       "16": "icons/icon-16.png",
       "48": "icons/icon-48.png",
diff --git a/extension/sidepanel.css b/extension/sidepanel.css
index 87ecf7b7..c5aea6ac 100644
--- a/extension/sidepanel.css
+++ b/extension/sidepanel.css
@@ -1,32 +1,54 @@
-/* gstack browse — Side Panel dark theme */
-/* Design tokens from cookie picker, extended */
+/* gstack browse — Side Panel
+ * Design system: DESIGN.md (Industrial/Utilitarian, amber accent, zinc neutrals)
+ */
 
 * { margin: 0; padding: 0; box-sizing: border-box; }
 
 :root {
-  --bg-body: #0a0a0a;
-  --bg-header: #0f0f0f;
-  --bg-surface: #1a1a1a;
-  --bg-hover: #151515;
-  --border: #222;
-  --border-inactive: #333;
-  --border-hover: #555;
-  --text-heading: #fff;
+  /* Brand — amber accent, rare and meaningful */
+  --amber-400: #FBBF24;
+  --amber-500: #F59E0B;
+  --amber-600: #D97706;
+
+  /* Neutrals — cool zinc */
+  --zinc-50: #FAFAFA;
+  --zinc-400: #A1A1AA;
+  --zinc-600: #52525B;
+  --zinc-800: #27272A;
+
+  /* Surfaces */
+  --bg-base: #0C0C0C;
+  --bg-surface: #141414;
+  --bg-hover: #1a1a1a;
+  --border: #262626;
+  --border-subtle: #1f1f1f;
+
+  /* Text hierarchy */
+  --text-heading: #FAFAFA;
   --text-body: #e0e0e0;
-  --text-label: #888;
-  --text-meta: #666;
-  --text-disabled: #555;
-  --green: #4ade80;
-  --red: #f87171;
-  --blue: #60a5fa;
-  --purple: #a78bfa;
-  --amber: #fbbf24;
+  --text-label: #A1A1AA;
+  --text-meta: #52525B;
+  --text-disabled: #3f3f46;
+
+  /* Semantic */
+  --success: #22C55E;
+  --warning: #F59E0B;
+  --error: #EF4444;
+  --info: #3B82F6;
+
+  /* Typography */
   --font-system: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
-  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
+  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
+
+  /* Radius */
+  --radius-sm: 4px;
+  --radius-md: 8px;
+  --radius-lg: 12px;
+  --radius-full: 9999px;
 }
 
 body {
-  background: var(--bg-body);
+  background: var(--bg-base);
   color: var(--text-body);
   font-family: var(--font-system);
   font-size: 13px;
@@ -36,55 +58,145 @@ body {
   overflow: hidden;
 }
 
-/* ─── Header ──────────────────────────────────────────── */
-header {
-  height: 40px;
-  background: var(--bg-header);
-  border-bottom: 1px solid var(--border);
-  display: flex;
-  align-items: center;
-  justify-content: space-between;
-  padding: 0 12px;
-  flex-shrink: 0;
+/* Grain texture overlay */
+body::after {
+  content: '';
+  position: fixed;
+  top: 0; left: 0; right: 0; bottom: 0;
+  pointer-events: none;
+  z-index: 9999;
+  opacity: 0.03;
+  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
 }
-.header-left { display: flex; align-items: center; gap: 8px; }
-.monogram {
-  width: 22px;
-  height: 22px;
-  background: var(--green);
-  color: #000;
-  font-weight: 700;
-  font-size: 13px;
-  border-radius: 4px;
-  display: flex;
-  align-items: center;
-  justify-content: center;
-}
-.title { color: var(--text-heading); font-weight: 600; font-size: 14px; letter-spacing: -0.3px; }
-.header-right { display: flex; align-items: center; gap: 6px; }
-.header-port { color: var(--text-meta); font-family: var(--font-mono); font-size: 11px; }
 
 /* ─── Status Dot ──────────────────────────────────────── */
 .dot {
   width: 8px; height: 8px;
-  border-radius: 50%;
+  border-radius: var(--radius-full);
   background: var(--text-disabled);
   flex-shrink: 0;
+  transition: background 150ms;
 }
-.dot.connected { background: var(--green); }
+.dot.connected { background: var(--success); }
 .dot.reconnecting {
-  background: var(--amber);
-  animation: pulse 1.5s ease-in-out infinite;
+  background: var(--amber-500);
+  animation: pulse 2s ease-in-out infinite;
 }
 @keyframes pulse {
   0%, 100% { opacity: 0.4; }
   50% { opacity: 1; }
 }
 
+/* ─── Chat Messages ───────────────────────────────────── */
+.chat-messages {
+  flex: 1;
+  overflow-y: auto;
+  padding: 12px;
+  display: flex;
+  flex-direction: column;
+  gap: 8px;
+}
+.chat-welcome {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  height: 100%;
+  text-align: center;
+  color: var(--text-label);
+  gap: 8px;
+  padding: 24px;
+}
+.chat-welcome-icon {
+  width: 40px;
+  height: 40px;
+  background: var(--amber-500);
+  color: #000;
+  font-weight: 800;
+  font-size: 22px;
+  border-radius: var(--radius-md);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  margin-bottom: 8px;
+}
+.chat-welcome .muted { color: var(--text-meta); font-size: 12px; }
+
+.chat-bubble {
+  max-width: 90%;
+  padding: 8px 12px;
+  border-radius: var(--radius-lg);
+  font-size: 13px;
+  line-height: 1.5;
+  word-break: break-word;
+  animation: slideIn 150ms ease-out;
+}
+.chat-bubble.user {
+  align-self: flex-end;
+  background: var(--amber-500);
+  color: #000;
+  border-bottom-right-radius: var(--radius-sm);
+}
+.chat-bubble.assistant {
+  align-self: flex-start;
+  background: var(--bg-surface);
+  color: var(--text-body);
+  border: 1px solid var(--border);
+  border-bottom-left-radius: var(--radius-sm);
+}
+.chat-bubble.assistant pre {
+  background: var(--bg-base);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  padding: 6px 8px;
+  margin: 6px 0;
+  overflow-x: auto;
+  font-family: var(--font-mono);
+  font-size: 12px;
+  white-space: pre-wrap;
+}
+.chat-bubble .chat-time {
+  font-size: 10px;
+  opacity: 0.5;
+  margin-top: 4px;
+  display: block;
+}
+
+/* ─── Debug Toggle ────────────────────────────────────── */
+.debug-toggle {
+  background: none;
+  border: 1px solid var(--border);
+  border-radius: var(--radius-sm);
+  color: var(--text-meta);
+  font-family: var(--font-mono);
+  font-size: 10px;
+  padding: 2px 6px;
+  cursor: pointer;
+  transition: all 150ms;
+}
+.debug-toggle:hover {
+  color: var(--text-label);
+  border-color: var(--zinc-600);
+}
+.debug-toggle.active {
+  color: var(--amber-400);
+  border-color: var(--amber-500);
+}
+.debug-tabs {
+  border-top: 1px solid var(--border);
+}
+.close-debug {
+  width: 36px;
+  flex: none !important;
+  font-size: 16px;
+  color: var(--text-meta) !important;
+}
+.close-debug:hover { color: var(--text-label) !important; }
+
 /* ─── Tab Bar ─────────────────────────────────────────── */
 .tabs {
   height: 36px;
-  background: var(--bg-header);
+  background: var(--bg-surface);
   border-bottom: 1px solid var(--border);
   display: flex;
   flex-shrink: 0;
@@ -98,12 +210,12 @@ header {
   font-weight: 500;
   cursor: pointer;
   border-bottom: 2px solid transparent;
-  transition: all 0.15s;
+  transition: all 150ms;
 }
-.tab:hover:not(.disabled) { color: #ccc; }
+.tab:hover:not(.disabled) { color: var(--zinc-50); }
 .tab.active {
   color: var(--text-heading);
-  border-bottom-color: var(--green);
+  border-bottom-color: var(--amber-500);
 }
 .tab.disabled {
   color: var(--text-disabled);
@@ -125,10 +237,10 @@ header {
 .activity-entry {
   padding: 8px 12px;
   border-left: 3px solid var(--border);
-  border-bottom: 1px solid var(--border);
+  border-bottom: 1px solid var(--border-subtle);
   cursor: pointer;
-  transition: background 0.15s;
-  animation: slideIn 0.15s ease;
+  transition: background 150ms;
+  animation: slideIn 150ms ease-out;
 }
 .activity-entry:hover { background: var(--bg-hover); }
 
@@ -142,17 +254,17 @@ header {
 }
 
 /* Left border colors by type */
-.activity-entry.nav { border-left-color: var(--blue); }
-.activity-entry.interaction { border-left-color: var(--green); }
-.activity-entry.observe { border-left-color: var(--purple); }
-.activity-entry.error { border-left-color: var(--red); }
+.activity-entry.nav { border-left-color: var(--info); }
+.activity-entry.interaction { border-left-color: var(--success); }
+.activity-entry.observe { border-left-color: var(--amber-400); }
+.activity-entry.error { border-left-color: var(--error); }
 .activity-entry.pending {
-  border-left-color: var(--amber);
-  animation: slideIn 0.15s ease, borderPulse 1.5s ease-in-out infinite;
+  border-left-color: var(--amber-500);
+  animation: slideIn 150ms ease-out, borderPulse 2s ease-in-out infinite;
 }
 @keyframes borderPulse {
-  0%, 100% { border-left-color: rgba(251, 191, 36, 0.4); }
-  50% { border-left-color: rgba(251, 191, 36, 1); }
+  0%, 100% { border-left-color: rgba(245, 158, 11, 0.3); }
+  50% { border-left-color: rgba(245, 158, 11, 1); }
 }
 
 .entry-header {
@@ -188,8 +300,8 @@ header {
   align-items: center;
   gap: 4px;
 }
-.entry-status .ok { color: var(--green); }
-.entry-status .err { color: var(--red); }
+.entry-status .ok { color: var(--success); }
+.entry-status .err { color: var(--error); }
 .entry-status .duration { color: var(--text-meta); }
 
 /* Expanded state */
@@ -202,7 +314,7 @@ header {
 .activity-entry.expanded .entry-detail { display: block; }
 .activity-entry.expanded .entry-args { white-space: normal; }
 .entry-result {
-  color: #aaa;
+  color: var(--zinc-400);
   font-family: var(--font-mono);
   font-size: 12px;
   white-space: pre-wrap;
@@ -216,11 +328,11 @@ header {
   align-items: center;
   gap: 8px;
   padding: 0 12px;
-  border-bottom: 1px solid var(--border);
+  border-bottom: 1px solid var(--border-subtle);
   font-size: 12px;
 }
 .ref-id {
-  color: var(--green);
+  color: var(--amber-400);
   font-family: var(--font-mono);
   font-weight: 600;
   min-width: 32px;
@@ -271,29 +383,97 @@ header {
 .empty-state code {
   background: var(--bg-surface);
   padding: 2px 6px;
-  border-radius: 3px;
+  border-radius: var(--radius-sm);
   font-family: var(--font-mono);
   font-size: 12px;
 }
 
 /* ─── Gap Banner ──────────────────────────────────────── */
 .gap-banner {
-  background: rgba(251, 191, 36, 0.1);
-  border-bottom: 1px solid var(--amber);
-  color: var(--amber);
+  background: rgba(245, 158, 11, 0.08);
+  border-bottom: 1px solid var(--amber-500);
+  color: var(--amber-400);
   font-size: 11px;
   padding: 6px 12px;
-  animation: bannerSlide 0.2s ease;
+  animation: bannerSlide 250ms ease-out;
 }
 @keyframes bannerSlide {
   from { transform: translateY(-100%); }
   to { transform: translateY(0); }
 }
 
+/* ─── Command Bar ─────────────────────────────────────── */
+.command-bar {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+  padding: 8px 12px;
+  background: var(--bg-surface);
+  border-top: 1px solid var(--border);
+  flex-shrink: 0;
+}
+.command-prompt {
+  color: var(--amber-500);
+  font-family: var(--font-mono);
+  font-size: 14px;
+  font-weight: 700;
+  flex-shrink: 0;
+  user-select: none;
+}
+.command-input {
+  flex: 1;
+  background: var(--bg-base);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-md);
+  padding: 8px 10px;
+  color: var(--text-heading);
+  font-family: var(--font-system);
+  font-size: 13px;
+  outline: none;
+  transition: border-color 150ms;
+}
+.command-input:focus { border-color: var(--amber-500); }
+.command-input::placeholder { color: var(--text-disabled); font-size: 12px; }
+.command-input.sent {
+  border-color: var(--success);
+  transition: border-color 150ms;
+}
+.command-input.error {
+  border-color: var(--error);
+  animation: shake 300ms ease;
+}
+@keyframes shake {
+  0%, 100% { transform: translateX(0); }
+  25% { transform: translateX(-4px); }
+  75% { transform: translateX(4px); }
+}
+.send-btn {
+  width: 32px;
+  height: 32px;
+  background: var(--amber-500);
+  border: none;
+  border-radius: var(--radius-md);
+  color: #000;
+  font-size: 16px;
+  font-weight: 700;
+  cursor: pointer;
+  flex-shrink: 0;
+  transition: all 150ms;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+}
+.send-btn:hover { background: var(--amber-400); }
+.send-btn:active { transform: scale(0.93); }
+.send-btn:disabled {
+  opacity: 0.3;
+  cursor: not-allowed;
+}
+
 /* ─── Footer ──────────────────────────────────────────── */
 footer {
   height: 32px;
-  background: var(--bg-header);
+  background: var(--bg-surface);
   border-top: 1px solid var(--border);
   display: flex;
   align-items: center;
@@ -307,11 +487,37 @@ footer {
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
-  max-width: 60%;
+  max-width: 50%;
 }
+.footer-right {
+  display: flex;
+  align-items: center;
+  gap: 6px;
+}
+.footer-port {
+  color: var(--text-meta);
+  font-family: var(--font-mono);
+  font-size: 11px;
+  cursor: pointer;
+  transition: color 150ms;
+}
+.footer-port:hover { color: var(--text-label); }
+.port-input {
+  width: 56px;
+  padding: 2px 6px;
+  background: var(--bg-base);
+  border: 1px solid var(--zinc-600);
+  border-radius: var(--radius-sm);
+  color: var(--text-heading);
+  font-family: var(--font-mono);
+  font-size: 11px;
+  outline: none;
+  transition: border-color 150ms;
+}
+.port-input:focus { border-color: var(--amber-500); }
 
 /* ─── Accessibility ───────────────────────────────────── */
 :focus-visible {
-  outline: 2px solid var(--green);
+  outline: 2px solid var(--amber-500);
   outline-offset: 1px;
 }
diff --git a/extension/sidepanel.html b/extension/sidepanel.html
index ca519ea3..16cb6483 100644
--- a/extension/sidepanel.html
+++ b/extension/sidepanel.html
@@ -5,27 +5,19 @@
   <link rel="stylesheet" href="sidepanel.css">
 </head>
 <body>
-  <!-- Header -->
-  <header>
-    <div class="header-left">
-      <span class="monogram">G</span>
-      <span class="title">gstack</span>
+  <!-- Chat Tab (default, full height) -->
+  <main id="tab-chat" class="tab-content active">
+    <div class="chat-messages" id="chat-messages">
+      <div class="chat-welcome">
+        <div class="chat-welcome-icon">G</div>
+        <p>Send a message to Claude Code.</p>
+        <p class="muted">Your agent will see it and act on it.</p>
+      </div>
     </div>
-    <div class="header-right">
-      <span class="dot" id="header-dot"></span>
-      <span class="header-port" id="header-port"></span>
-    </div>
-  </header>
+  </main>
 
-  <!-- Tab Bar -->
-  <nav class="tabs" role="tablist">
-    <button class="tab active" role="tab" aria-selected="true" data-tab="activity">Activity</button>
-    <button class="tab" role="tab" aria-selected="false" data-tab="refs">Refs</button>
-    <button class="tab disabled" role="tab" aria-selected="false" data-tab="session" disabled title="Requires Conductor">Session</button>
-  </nav>
-
-  <!-- Activity Tab -->
-  <main id="tab-activity" class="tab-content active" role="log" aria-live="polite">
+  <!-- Debug: Activity Tab (hidden by default) -->
+  <main id="tab-activity" class="tab-content" role="log" aria-live="polite">
     <div class="empty-state" id="empty-state">
       <p>Waiting for commands...</p>
       <p class="muted">Run a browse command to see activity here.</p>
@@ -33,7 +25,7 @@
     <div id="activity-feed"></div>
   </main>
 
-  <!-- Refs Tab -->
+  <!-- Debug: Refs Tab (hidden by default) -->
   <main id="tab-refs" class="tab-content">
     <div class="empty-state" id="refs-empty">
       <p>No refs yet</p>
@@ -43,20 +35,29 @@
     <div class="refs-footer" id="refs-footer"></div>
   </main>
 
-  <!-- Session Tab -->
-  <main id="tab-session" class="tab-content">
-    <div class="session-placeholder">
-      <p>Full session view requires Conductor.</p>
-      <p class="muted">Activity tab shows browse commands.</p>
-    </div>
-  </main>
+  <!-- Command Bar -->
+  <div class="command-bar">
+    <input type="text" class="command-input" id="command-input" placeholder="Message Claude Code..." autocomplete="off" spellcheck="false">
+    <button class="send-btn" id="send-btn" title="Send">&#x2191;</button>
+  </div>
 
-  <!-- Footer -->
+  <!-- Footer with connection + debug toggle -->
   <footer>
-    <span id="footer-url"></span>
-    <span id="footer-info"></span>
+    <button class="debug-toggle" id="debug-toggle" title="Toggle debug panels">debug</button>
+    <div class="footer-right">
+      <span class="dot" id="footer-dot"></span>
+      <span class="footer-port" id="footer-port" title="Click to change port"></span>
+      <input type="text" class="port-input" id="port-input" placeholder="34567" autocomplete="off" style="display:none">
+    </div>
   </footer>
 
+  <!-- Debug tab bar (hidden by default) -->
+  <nav class="tabs debug-tabs" id="debug-tabs" role="tablist" style="display:none">
+    <button class="tab" role="tab" data-tab="activity">Activity</button>
+    <button class="tab" role="tab" data-tab="refs">Refs</button>
+    <button class="tab close-debug" id="close-debug" title="Close debug">&times;</button>
+  </nav>
+
   <script src="sidepanel.js"></script>
 </body>
 </html>
diff --git a/extension/sidepanel.js b/extension/sidepanel.js
index 007e22c4..2a56cbf2 100644
--- a/extension/sidepanel.js
+++ b/extension/sidepanel.js
@@ -1,9 +1,9 @@
 /**
  * gstack browse — Side Panel
  *
- * Connects to browse server SSE stream for live activity.
- * Fetches /refs for the Refs tab.
- * Cursor-based replay ensures no missed events on reconnect.
+ * Chat tab: two-way messaging with Claude Code via file queue.
+ * Debug tabs: activity feed (SSE) + refs (REST).
+ * Polls /sidebar-chat for new messages every 1s.
  */
 
 const NAV_COMMANDS = new Set(['goto', 'back', 'forward', 'reload']);
@@ -13,23 +13,146 @@ const OBSERVE_COMMANDS = new Set(['snapshot', 'screenshot', 'diff', 'console', '
 let lastId = 0;
 let eventSource = null;
 let serverUrl = null;
-let pendingEntries = new Map(); // id → entry element (for command_start without command_end)
+let chatLineCount = 0;
+let chatPollInterval = null;
 
-// ─── Tab Switching ─────────────────────────────────────────────
+// ─── Chat ───────────────────────────────────────────────────────
 
-document.querySelectorAll('.tab:not(.disabled)').forEach(tab => {
+const chatMessages = document.getElementById('chat-messages');
+const commandInput = document.getElementById('command-input');
+const sendBtn = document.getElementById('send-btn');
+const commandHistory = [];
+let historyIndex = -1;
+
+function formatChatTime(ts) {
+  const d = new Date(ts);
+  return d.toLocaleTimeString('en-US', { hour12: false, hour: '2-digit', minute: '2-digit' });
+}
+
+function addChatBubble(entry) {
+  // Remove welcome message on first real message
+  const welcome = chatMessages.querySelector('.chat-welcome');
+  if (welcome) welcome.remove();
+
+  const bubble = document.createElement('div');
+  bubble.className = `chat-bubble ${entry.role}`;
+
+  let content = escapeHtml(entry.message);
+  // Simple markdown-ish: wrap ```...``` in <pre>
+  content = content.replace(/```([\s\S]*?)```/g, '<pre>$1</pre>');
+  // Bold **text**
+  content = content.replace(/\*\*(.*?)\*\*/g, '<strong>$1</strong>');
+  // Line breaks
+  content = content.replace(/\n/g, '<br>');
+
+  bubble.innerHTML = `${content}<span class="chat-time">${formatChatTime(entry.ts)}</span>`;
+  chatMessages.appendChild(bubble);
+  bubble.scrollIntoView({ behavior: 'smooth', block: 'end' });
+}
+
+async function sendMessage() {
+  const msg = commandInput.value.trim();
+  if (!msg) return;
+
+  commandHistory.push(msg);
+  historyIndex = commandHistory.length;
+  commandInput.value = '';
+  commandInput.disabled = true;
+  sendBtn.disabled = true;
+
+  const result = await new Promise((resolve) => {
+    chrome.runtime.sendMessage({ type: 'sidebar-command', message: msg }, resolve);
+  });
+
+  commandInput.disabled = false;
+  sendBtn.disabled = false;
+  commandInput.focus();
+
+  if (result?.ok) {
+    // Immediately poll to show the user's own message
+    pollChat();
+  } else {
+    commandInput.classList.add('error');
+    commandInput.placeholder = result?.error || 'Failed to send';
+    setTimeout(() => {
+      commandInput.classList.remove('error');
+      commandInput.placeholder = 'Message Claude Code...';
+    }, 2000);
+  }
+}
+
+commandInput.addEventListener('keydown', (e) => {
+  if (e.key === 'Enter') { e.preventDefault(); sendMessage(); }
+  if (e.key === 'ArrowUp') {
+    e.preventDefault();
+    if (historyIndex > 0) { historyIndex--; commandInput.value = commandHistory[historyIndex]; }
+  }
+  if (e.key === 'ArrowDown') {
+    e.preventDefault();
+    if (historyIndex < commandHistory.length - 1) { historyIndex++; commandInput.value = commandHistory[historyIndex]; }
+    else { historyIndex = commandHistory.length; commandInput.value = ''; }
+  }
+});
+
+sendBtn.addEventListener('click', sendMessage);
+
+// Poll for new chat messages
+async function pollChat() {
+  if (!serverUrl) return;
+  try {
+    const resp = await fetch(`${serverUrl}/sidebar-chat?after=${chatLineCount}`, {
+      signal: AbortSignal.timeout(3000),
+    });
+    if (!resp.ok) return;
+    const data = await resp.json();
+    if (data.entries && data.entries.length > 0) {
+      for (const entry of data.entries) {
+        addChatBubble(entry);
+      }
+      chatLineCount = data.total;
+    }
+  } catch {}
+}
+
+// ─── Debug Tabs ─────────────────────────────────────────────────
+
+const debugToggle = document.getElementById('debug-toggle');
+const debugTabs = document.getElementById('debug-tabs');
+const closeDebug = document.getElementById('close-debug');
+let debugOpen = false;
+
+debugToggle.addEventListener('click', () => {
+  debugOpen = !debugOpen;
+  debugToggle.classList.toggle('active', debugOpen);
+  debugTabs.style.display = debugOpen ? 'flex' : 'none';
+  if (!debugOpen) {
+    // Close debug panels, show chat
+    document.querySelectorAll('.tab-content').forEach(c => c.classList.remove('active'));
+    document.getElementById('tab-chat').classList.add('active');
+    document.querySelectorAll('.debug-tabs .tab').forEach(t => t.classList.remove('active'));
+  }
+});
+
+closeDebug.addEventListener('click', () => {
+  debugOpen = false;
+  debugToggle.classList.remove('active');
+  debugTabs.style.display = 'none';
+  document.querySelectorAll('.tab-content').forEach(c => c.classList.remove('active'));
+  document.getElementById('tab-chat').classList.add('active');
+});
+
+document.querySelectorAll('.debug-tabs .tab:not(.close-debug)').forEach(tab => {
   tab.addEventListener('click', () => {
-    document.querySelectorAll('.tab').forEach(t => { t.classList.remove('active'); t.setAttribute('aria-selected', 'false'); });
+    document.querySelectorAll('.debug-tabs .tab').forEach(t => t.classList.remove('active'));
     document.querySelectorAll('.tab-content').forEach(c => c.classList.remove('active'));
     tab.classList.add('active');
-    tab.setAttribute('aria-selected', 'true');
     document.getElementById(`tab-${tab.dataset.tab}`).classList.add('active');
 
     if (tab.dataset.tab === 'refs') fetchRefs();
   });
 });
 
-// ─── Activity Feed ─────────────────────────────────────────────
+// ─── Activity Feed ──────────────────────────────────────────────
 
 function getEntryClass(entry) {
   if (entry.status === 'error') return 'error';
@@ -46,6 +169,8 @@ function formatTime(ts) {
   return d.toLocaleTimeString('en-US', { hour12: false, hour: '2-digit', minute: '2-digit', second: '2-digit' });
 }
 
+let pendingEntries = new Map();
+
 function createEntryElement(entry) {
   const div = document.createElement('div');
   div.className = `activity-entry ${getEntryClass(entry)}`;
@@ -76,17 +201,7 @@ function createEntryElement(entry) {
     ` : ''}
   `;
 
-  // Click to expand/collapse
   div.addEventListener('click', () => div.classList.toggle('expanded'));
-  div.addEventListener('keydown', (e) => {
-    if (e.key === 'Enter') div.classList.toggle('expanded');
-    if (e.key === 'Escape') div.classList.remove('expanded');
-  });
-
-  // Screen reader label
-  const srLabel = `${entry.command || entry.type} ${argsText} ${statusIcon ? (entry.status === 'ok' ? 'succeeded' : 'failed') : 'in progress'} ${duration ? 'in ' + duration : ''}`;
-  div.setAttribute('aria-label', srLabel);
-
   return div;
 }
 
@@ -95,9 +210,7 @@ function addEntry(entry) {
   const empty = document.getElementById('empty-state');
   if (empty) empty.style.display = 'none';
 
-  // If command_end, update the matching pending entry
   if (entry.type === 'command_end') {
-    // Remove the pending command_start for this command
     for (const [id, el] of pendingEntries) {
       if (el.querySelector('.entry-command')?.textContent === entry.command) {
         el.remove();
@@ -109,21 +222,10 @@ function addEntry(entry) {
 
   const el = createEntryElement(entry);
   feed.appendChild(el);
-
-  if (entry.type === 'command_start') {
-    pendingEntries.set(entry.id, el);
-  }
-
-  // Auto-scroll
+  if (entry.type === 'command_start') pendingEntries.set(entry.id, el);
   el.scrollIntoView({ behavior: 'smooth', block: 'end' });
 
-  // Update footer
-  if (entry.url) document.getElementById('footer-url').textContent = new URL(entry.url).hostname;
-  const parts = [];
-  if (entry.tabs) parts.push(`${entry.tabs} tabs`);
-  if (entry.mode) parts.push(entry.mode);
-  if (parts.length) document.getElementById('footer-info').textContent = parts.join(' \u00b7 ');
-
+  if (entry.url) document.getElementById('footer-url')?.textContent && (document.getElementById('footer-url').textContent = new URL(entry.url).hostname);
   lastId = Math.max(lastId, entry.id);
 }
 
@@ -133,24 +235,17 @@ function escapeHtml(str) {
   return div.innerHTML;
 }
 
-// ─── SSE Connection ────────────────────────────────────────────
+// ─── SSE Connection ─────────────────────────────────────────────
 
 function connectSSE() {
   if (!serverUrl) return;
-
-  if (eventSource) {
-    eventSource.close();
-    eventSource = null;
-  }
+  if (eventSource) { eventSource.close(); eventSource = null; }
 
   const url = `${serverUrl}/activity/stream?after=${lastId}`;
   eventSource = new EventSource(url);
 
   eventSource.addEventListener('activity', (e) => {
-    try {
-      const entry = JSON.parse(e.data);
-      addEntry(entry);
-    } catch {}
+    try { addEntry(JSON.parse(e.data)); } catch {}
   });
 
   eventSource.addEventListener('gap', (e) => {
@@ -159,17 +254,13 @@ function connectSSE() {
       const feed = document.getElementById('activity-feed');
       const banner = document.createElement('div');
       banner.className = 'gap-banner';
-      banner.textContent = `Missed ${data.availableFrom - data.gapFrom} events (buffer overflow)`;
+      banner.textContent = `Missed ${data.availableFrom - data.gapFrom} events`;
       feed.appendChild(banner);
     } catch {}
   });
-
-  eventSource.onerror = () => {
-    // EventSource auto-reconnects
-  };
 }
 
-// ─── Refs Tab ──────────────────────────────────────────────────
+// ─── Refs Tab ───────────────────────────────────────────────────
 
 async function fetchRefs() {
   if (!serverUrl) return;
@@ -197,29 +288,65 @@ async function fetchRefs() {
         <span class="ref-name">"${escapeHtml(r.name)}"</span>
       </div>
     `).join('');
-    footer.textContent = `${data.refs.length} refs \u00b7 ${data.url ? new URL(data.url).hostname : ''}`;
+    footer.textContent = `${data.refs.length} refs`;
   } catch {}
 }
 
-// ─── Server Discovery ──────────────────────────────────────────
+// ─── Server Discovery ───────────────────────────────────────────
 
 function updateConnection(url) {
   serverUrl = url;
   if (url) {
-    document.getElementById('header-dot').className = 'dot connected';
+    document.getElementById('footer-dot').className = 'dot connected';
     const port = new URL(url).port;
-    document.getElementById('header-port').textContent = `:${port}`;
+    document.getElementById('footer-port').textContent = `:${port}`;
     connectSSE();
+    // Start chat polling
+    if (chatPollInterval) clearInterval(chatPollInterval);
+    chatPollInterval = setInterval(pollChat, 1000);
+    pollChat();  // immediate first poll
   } else {
-    document.getElementById('header-dot').className = 'dot';
-    document.getElementById('header-port').textContent = '';
+    document.getElementById('footer-dot').className = 'dot';
+    document.getElementById('footer-port').textContent = '';
+    if (chatPollInterval) { clearInterval(chatPollInterval); chatPollInterval = null; }
   }
 }
 
+// ─── Port Configuration ─────────────────────────────────────────
+
+const portLabel = document.getElementById('footer-port');
+const portInput = document.getElementById('port-input');
+
+portLabel.addEventListener('click', () => {
+  portLabel.style.display = 'none';
+  portInput.style.display = '';
+  chrome.runtime.sendMessage({ type: 'getPort' }, (resp) => {
+    portInput.value = resp?.port || '';
+    portInput.focus();
+    portInput.select();
+  });
+});
+
+function savePort() {
+  const port = parseInt(portInput.value, 10);
+  if (port > 0 && port < 65536) {
+    chrome.runtime.sendMessage({ type: 'setPort', port });
+  }
+  portInput.style.display = 'none';
+  portLabel.style.display = '';
+}
+portInput.addEventListener('blur', savePort);
+portInput.addEventListener('keydown', (e) => {
+  if (e.key === 'Enter') savePort();
+  if (e.key === 'Escape') { portInput.style.display = 'none'; portLabel.style.display = ''; }
+});
+
 chrome.runtime.sendMessage({ type: 'getServerUrl' }, (resp) => {
   if (resp && resp.url) updateConnection(resp.url);
 });
 
+// ─── Message Listener ───────────────────────────────────────────
+
 chrome.runtime.onMessage.addListener((msg) => {
   if (msg.type === 'health') {
     chrome.runtime.sendMessage({ type: 'getServerUrl' }, (resp) => {
@@ -227,7 +354,6 @@ chrome.runtime.onMessage.addListener((msg) => {
     });
   }
   if (msg.type === 'refs') {
-    // Auto-refresh refs tab if visible
     if (document.querySelector('.tab[data-tab="refs"].active')) {
       fetchRefs();
     }