diff --git a/frontend/src/components/copilot/CopilotMessage.vue b/frontend/src/components/copilot/CopilotMessage.vue
new file mode 100644
index 0000000..9fdf9bc
--- /dev/null
+++ b/frontend/src/components/copilot/CopilotMessage.vue
@@ -0,0 +1,117 @@
+<template>
+  <div
+    class="flex mb-3"
+    :class="message.role === 'user' ? 'justify-end' : 'justify-start'"
+  >
+    <div
+      class="max-w-[90%] rounded-lg px-3 py-2 text-sm bg-[#161b22] border-l-2"
+      :class="message.role === 'user' ? 'border-[#58a6ff]' : 'border-[#3fb950]'"
+    >
+      <!-- Rendered content -->
+      <div
+        v-if="message.role === 'assistant'"
+        class="copilot-md text-[#e0e0e0] leading-relaxed break-words"
+        v-html="renderedContent"
+      />
+      <div v-else class="text-[#e0e0e0] leading-relaxed break-words whitespace-pre-wrap">
+        {{ message.content }}
+      </div>
+
+      <!-- Tool call visualizations (assistant only) -->
+      <CopilotToolViz
+        v-for="tc in message.toolCalls"
+        :key="tc.id"
+        :tool-call="tc"
+      />
+
+      <!-- Streaming cursor -->
+      <span
+        v-if="isStreaming && message.role === 'assistant'"
+        class="inline-block w-2 h-4 bg-[#3fb950] align-middle animate-pulse ml-0.5"
+      />
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed } from "vue";
+import type { Message } from "@/stores/copilot.store";
+import CopilotToolViz from "./CopilotToolViz.vue";
+
+const props = defineProps<{
+  message: Message;
+  isStreaming?: boolean;
+}>();
+
+/**
+ * Simple regex-based markdown renderer.
+ * Handles: bold, inline code, code blocks, list items, newlines.
+ * No external library needed.
+ */
+const renderedContent = computed(() => {
+  let text = props.message.content;
+
+  // Escape HTML
+  text = text
+    .replace(/&/g, "&amp;")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;");
+
+  // Code blocks (```...```)
+  text = text.replace(
+    /```(\w*)\n?([\s\S]*?)```/g,
+    '<pre class="bg-[#0d1117] rounded p-2 my-1.5 overflow-x-auto text-xs font-mono"><code>$2</code></pre>',
+  );
+
+  // Inline code (`...`)
+  text = text.replace(
+    /`([^`]+)`/g,
+    '<code class="bg-[#0d1117] text-[#79c0ff] px-1 py-0.5 rounded text-xs font-mono">$1</code>',
+  );
+
+  // Bold (**...**)
+  text = text.replace(/\*\*(.+?)\*\*/g, "<strong>$1</strong>");
+
+  // Italic (*...*)
+  text = text.replace(/\*(.+?)\*/g, "<em>$1</em>");
+
+  // List items (- item)
+  text = text.replace(/^- (.+)$/gm, '<li class="ml-3 list-disc">$1</li>');
+
+  // Wrap consecutive <li> in <ul>
+  text = text.replace(
+    /(<li[^>]*>.*?<\/li>\n?)+/g,
+    '<ul class="my-1">$&</ul>',
+  );
+
+  // Newlines to <br> (except inside <pre>)
+  text = text.replace(/\n(?!<\/?pre|<\/?ul|<\/?li)/g, "<br>");
+
+  return text;
+});
+</script>
+
+<style scoped>
+/* Markdown styling within copilot messages */
+.copilot-md :deep(strong) {
+  color: #e0e0e0;
+  font-weight: 600;
+}
+
+.copilot-md :deep(em) {
+  color: #8b949e;
+  font-style: italic;
+}
+
+.copilot-md :deep(code) {
+  font-family: 'JetBrains Mono', 'Fira Code', monospace;
+}
+
+.copilot-md :deep(pre) {
+  font-family: 'JetBrains Mono', 'Fira Code', monospace;
+}
+
+.copilot-md :deep(ul) {
+  padding-left: 0.5rem;
+}
+</style>
diff --git a/frontend/src/components/copilot/CopilotPanel.vue b/frontend/src/components/copilot/CopilotPanel.vue
new file mode 100644
index 0000000..70c9fae
--- /dev/null
+++ b/frontend/src/components/copilot/CopilotPanel.vue
@@ -0,0 +1,237 @@
+<template>
+  <div
+    class="flex flex-col h-full bg-[#0d1117] border-l border-[#30363d] overflow-hidden"
+    :style="{ width: panelWidth + 'px' }"
+  >
+    <!-- Header -->
+    <div class="flex items-center justify-between px-3 py-2 bg-[#161b22] border-b border-[#30363d] shrink-0">
+      <div class="flex items-center gap-2">
+        <!-- Ghost icon -->
+        <span class="text-base" title="XO AI Copilot">{{ ghostIcon }}</span>
+        <span class="text-sm font-bold text-[#58a6ff]">XO</span>
+        <span class="text-[10px] text-[#484f58]">{{ modelShort }}</span>
+      </div>
+      <div class="flex items-center gap-2">
+        <!-- Token counter -->
+        <span class="text-[10px] text-[#484f58]">
+          {{ formatTokens(store.tokenUsage.input) }} / {{ formatTokens(store.tokenUsage.output) }}
+        </span>
+        <!-- Settings button -->
+        <button
+          class="text-[#8b949e] hover:text-[#e0e0e0] transition-colors cursor-pointer"
+          title="Settings"
+          @click="store.showSettings = true"
+        >
+          <svg class="w-3.5 h-3.5" viewBox="0 0 16 16" fill="currentColor">
+            <path fill-rule="evenodd" d="M7.429 1.525a6.593 6.593 0 011.142 0c.036.003.108.036.137.146l.289 1.105c.147.56.55.967.997 1.189.174.086.341.183.501.29.417.278.97.423 1.53.27l1.102-.303c.11-.03.175.016.195.046.219.31.41.641.573.989.014.031.022.11-.059.19l-.815.806c-.411.406-.562.957-.53 1.456a4.588 4.588 0 010 .582c-.032.499.119 1.05.53 1.456l.815.806c.08.08.073.159.059.19a6.494 6.494 0 01-.573.99c-.02.029-.086.074-.195.045l-1.103-.303c-.559-.153-1.112-.008-1.529.27-.16.107-.327.204-.5.29-.449.222-.851.628-.998 1.189l-.289 1.105c-.029.11-.101.143-.137.146a6.613 6.613 0 01-1.142 0c-.036-.003-.108-.037-.137-.146l-.289-1.105c-.147-.56-.55-.967-.997-1.189a4.502 4.502 0 01-.501-.29c-.417-.278-.97-.423-1.53-.27l-1.102.303c-.11.03-.175-.016-.195-.046a6.492 6.492 0 01-.573-.989c-.014-.031-.022-.11.059-.19l.815-.806c.411-.406.562-.957.53-1.456a4.587 4.587 0 010-.582c.032-.499-.119-1.05-.53-1.456l-.815-.806c-.08-.08-.073-.159-.059-.19a6.44 6.44 0 01.573-.99c.02-.029.086-.074.195-.045l1.103.303c.559.153 1.112.008 1.529-.27.16-.107.327-.204.5-.29.449-.222.851-.628.998-1.189l.289-1.105c.029-.11.101-.143.137-.146zM8 0c-.236 0-.47.01-.701.03-.743.065-1.29.615-1.458 1.261l-.29 1.106c-.017.066-.078.158-.211.224a5.994 5.994 0 00-.668.386c-.123.082-.233.117-.3.1L3.27 2.801c-.635-.175-1.322.017-1.768.681A7.963 7.963 0 00.767 4.905c-.324.627-.2 1.358.246 1.8l.816.806c.049.048.098.153.088.313a6.088 6.088 0 000 .352c.01.16-.04.265-.088.313l-.816.806c-.446.443-.57 1.173-.246 1.8a7.96 7.96 0 00.736 1.323c.446.664 1.133.856 1.768.681l1.103-.303c.066-.018.177.018.3.1.22.147.447.28.668.386.133.066.194.158.212.224l.289 1.106c.169.646.715 1.196 1.458 1.26a8.094 8.094 0 001.402 0c.743-.064 1.29-.614 1.458-1.26l.29-1.106c.017-.066.078-.158.211-.224a5.98 5.98 0 00.668-.386c.123-.082.233-.117.3-.1l1.102.302c.635.175 1.322-.017 1.768-.68a7.96 7.96 0 00.736-1.324c.324-.627.2-1.357-.246-1.8l-.816-.805c-.048-.048-.098-.153-.088-.313a6.15 6.15 0 000-.352c-.01-.16.04-.265.088-.313l.816-.806c.446-.443.57-1.173.246-1.8a7.963 7.963 0 00-.736-1.323c-.446-.664-1.133-.856-1.768-.681l-1.103.303c-.066.018-.176-.018-.3-.1a5.99 5.99 0 00-.667-.386c-.133-.066-.194-.158-.212-.224L10.16 1.29C9.99.645 9.444.095 8.701.031A8.094 8.094 0 008 0zm1.5 8a1.5 1.5 0 11-3 0 1.5 1.5 0 013 0zM11 8a3 3 0 11-6 0 3 3 0 016 0z" />
+          </svg>
+        </button>
+        <!-- Close button -->
+        <button
+          class="text-[#8b949e] hover:text-[#e0e0e0] transition-colors cursor-pointer"
+          title="Close panel (Ctrl+Shift+K)"
+          @click="store.togglePanel()"
+        >
+          <svg class="w-3.5 h-3.5" viewBox="0 0 16 16" fill="currentColor">
+            <path d="M3.72 3.72a.75.75 0 011.06 0L8 6.94l3.22-3.22a.75.75 0 111.06 1.06L9.06 8l3.22 3.22a.75.75 0 11-1.06 1.06L8 9.06l-3.22 3.22a.75.75 0 01-1.06-1.06L6.94 8 3.72 4.78a.75.75 0 010-1.06z" />
+          </svg>
+        </button>
+      </div>
+    </div>
+
+    <!-- Unauthenticated state -->
+    <div
+      v-if="!store.isAuthenticated"
+      class="flex-1 flex flex-col items-center justify-center px-6"
+    >
+      <span class="text-4xl mb-4">{{ ghostIcon }}</span>
+      <p class="text-sm text-[#8b949e] text-center mb-4">
+        Connect to Claude to activate the XO AI copilot.
+      </p>
+      <button
+        class="px-4 py-2 text-sm font-medium text-white bg-[#1f6feb] hover:bg-[#388bfd] rounded transition-colors cursor-pointer"
+        @click="store.startLogin()"
+      >
+        Connect to Claude
+      </button>
+    </div>
+
+    <!-- Message list -->
+    <div
+      v-else
+      ref="messageListRef"
+      class="flex-1 overflow-y-auto px-3 py-3"
+    >
+      <!-- Empty state -->
+      <div
+        v-if="store.messages.length === 0"
+        class="flex flex-col items-center justify-center h-full text-center"
+      >
+        <span class="text-3xl mb-3 opacity-40">{{ ghostIcon }}</span>
+        <p class="text-sm text-[#8b949e]">XO standing by.</p>
+        <p class="text-xs text-[#484f58] mt-1">Send a message to begin.</p>
+      </div>
+
+      <!-- Messages -->
+      <CopilotMessage
+        v-for="msg in store.messages"
+        :key="msg.id"
+        :message="msg"
+        :is-streaming="store.isStreaming && msg.id === lastAssistantId"
+      />
+    </div>
+
+    <!-- Input area (authenticated only) -->
+    <div
+      v-if="store.isAuthenticated"
+      class="shrink-0 border-t border-[#30363d] p-3 bg-[#161b22]"
+    >
+      <div class="flex gap-2">
+        <textarea
+          ref="inputRef"
+          v-model="inputText"
+          :disabled="store.isStreaming"
+          placeholder="Message the XO..."
+          rows="1"
+          class="flex-1 resize-none px-2.5 py-1.5 text-sm rounded bg-[#161b22] border border-[#30363d] text-[#e0e0e0] placeholder-[#484f58] outline-none focus:border-[#58a6ff] transition-colors disabled:opacity-50"
+          @keydown="handleInputKeydown"
+          @input="autoResize"
+        />
+        <button
+          class="shrink-0 px-2.5 py-1.5 rounded transition-colors cursor-pointer"
+          :class="
+            canSend
+              ? 'bg-[#1f6feb] hover:bg-[#388bfd] text-white'
+              : 'bg-[#21262d] text-[#484f58] cursor-not-allowed'
+          "
+          :disabled="!canSend"
+          title="Send message"
+          @click="handleSend"
+        >
+          <svg class="w-4 h-4" viewBox="0 0 16 16" fill="currentColor">
+            <path d="M.989 8 .064 2.68a1.342 1.342 0 0 1 1.85-1.462l13.402 5.744a1.13 1.13 0 0 1 0 2.076L1.913 14.782a1.343 1.343 0 0 1-1.85-1.463L.99 8Zm.603-5.108L2.18 7.25h4.57a.75.75 0 0 1 0 1.5H2.18l-.588 4.358L14.233 8 1.592 2.892Z" />
+          </svg>
+        </button>
+      </div>
+      <!-- Streaming indicator -->
+      <div v-if="store.isStreaming" class="flex items-center gap-1.5 mt-1.5 text-[10px] text-[#3fb950]">
+        <span class="w-1.5 h-1.5 rounded-full bg-[#3fb950] animate-pulse" />
+        XO is responding...
+      </div>
+    </div>
+
+    <!-- Settings modal -->
+    <CopilotSettings v-if="store.showSettings" @close="store.showSettings = false" />
+  </div>
+</template>
+
+<script setup lang="ts">
+import { ref, computed, watch, nextTick } from "vue";
+import { useCopilotStore } from "@/stores/copilot.store";
+import { useCopilot } from "@/composables/useCopilot";
+import CopilotMessage from "./CopilotMessage.vue";
+import CopilotSettings from "./CopilotSettings.vue";
+
+const store = useCopilotStore();
+const { processMessage } = useCopilot();
+
+const panelWidth = 320;
+const inputText = ref("");
+const inputRef = ref<HTMLTextAreaElement | null>(null);
+const messageListRef = ref<HTMLDivElement | null>(null);
+
+/** Short model name for header display. */
+const modelShort = computed(() => {
+  const m = store.model;
+  if (m.includes("sonnet")) return "sonnet";
+  if (m.includes("opus")) return "opus";
+  if (m.includes("haiku")) return "haiku";
+  return m;
+});
+
+/** Token formatter. */
+function formatTokens(n: number): string {
+  if (n >= 1000) return (n / 1000).toFixed(1) + "K";
+  return String(n);
+}
+
+/** ID of the last assistant message (for streaming cursor). */
+const lastAssistantId = computed(() => {
+  for (let i = store.messages.length - 1; i >= 0; i--) {
+    if (store.messages[i].role === "assistant") return store.messages[i].id;
+  }
+  return null;
+});
+
+/** Whether the send button should be active. */
+const canSend = computed(() => inputText.value.trim().length > 0 && !store.isStreaming);
+
+/** Send the message. */
+async function handleSend(): Promise<void> {
+  const text = inputText.value.trim();
+  if (!text || store.isStreaming) return;
+
+  inputText.value = "";
+  resetTextareaHeight();
+
+  store.sendMessage(text);
+  await nextTick();
+  scrollToBottom();
+
+  await processMessage(text);
+}
+
+/** Handle keyboard shortcuts in the input area. */
+function handleInputKeydown(event: KeyboardEvent): void {
+  if (event.key === "Enter" && !event.shiftKey) {
+    event.preventDefault();
+    handleSend();
+  }
+}
+
+/** Auto-resize textarea based on content. */
+function autoResize(): void {
+  const el = inputRef.value;
+  if (!el) return;
+  el.style.height = "auto";
+  el.style.height = Math.min(el.scrollHeight, 120) + "px";
+}
+
+/** Reset textarea height back to single line. */
+function resetTextareaHeight(): void {
+  const el = inputRef.value;
+  if (!el) return;
+  el.style.height = "auto";
+}
+
+/** Scroll the message list to the bottom. */
+function scrollToBottom(): void {
+  const el = messageListRef.value;
+  if (!el) return;
+  el.scrollTop = el.scrollHeight;
+}
+
+/** Auto-scroll when messages change or streaming content updates. */
+watch(
+  () => store.messages.length,
+  async () => {
+    await nextTick();
+    scrollToBottom();
+  },
+);
+
+watch(
+  () => {
+    const msgs = store.messages;
+    if (msgs.length === 0) return "";
+    return msgs[msgs.length - 1].content;
+  },
+  async () => {
+    await nextTick();
+    scrollToBottom();
+  },
+);
+
+// The ghost icon used in multiple places
+const ghostIcon = "\uD83D\uDC7B";
+</script>
diff --git a/frontend/src/components/copilot/CopilotSettings.vue b/frontend/src/components/copilot/CopilotSettings.vue
new file mode 100644
index 0000000..24ec541
--- /dev/null
+++ b/frontend/src/components/copilot/CopilotSettings.vue
@@ -0,0 +1,137 @@
+<template>
+  <!-- Backdrop -->
+  <div
+    class="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm"
+    @click.self="emit('close')"
+  >
+    <!-- Modal -->
+    <div class="w-80 bg-[#161b22] border border-[#30363d] rounded-lg shadow-2xl overflow-hidden">
+      <!-- Header -->
+      <div class="flex items-center justify-between px-4 py-3 border-b border-[#30363d]">
+        <h3 class="text-sm font-semibold text-[#e0e0e0]">XO Settings</h3>
+        <button
+          class="text-[#8b949e] hover:text-[#e0e0e0] transition-colors cursor-pointer"
+          @click="emit('close')"
+        >
+          <svg class="w-4 h-4" viewBox="0 0 16 16" fill="currentColor">
+            <path d="M3.72 3.72a.75.75 0 011.06 0L8 6.94l3.22-3.22a.75.75 0 111.06 1.06L9.06 8l3.22 3.22a.75.75 0 11-1.06 1.06L8 9.06l-3.22 3.22a.75.75 0 01-1.06-1.06L6.94 8 3.72 4.78a.75.75 0 010-1.06z" />
+          </svg>
+        </button>
+      </div>
+
+      <!-- Body -->
+      <div class="px-4 py-4 space-y-4">
+        <!-- Auth section -->
+        <div v-if="!store.isAuthenticated">
+          <button
+            class="w-full px-3 py-2 text-sm font-medium text-white bg-[#1f6feb] hover:bg-[#388bfd] rounded transition-colors cursor-pointer"
+            @click="handleLogin"
+          >
+            Connect to Claude
+          </button>
+
+          <div class="mt-3">
+            <label class="block text-xs text-[#8b949e] mb-1">Or enter API Key</label>
+            <input
+              v-model="apiKey"
+              type="password"
+              placeholder="sk-ant-..."
+              class="w-full px-2.5 py-1.5 text-xs rounded bg-[#0d1117] border border-[#30363d] text-[#e0e0e0] placeholder-[#484f58] outline-none focus:border-[#58a6ff] transition-colors"
+            />
+            <button
+              class="mt-2 w-full px-3 py-1.5 text-xs font-medium text-[#e0e0e0] bg-[#21262d] hover:bg-[#30363d] border border-[#30363d] rounded transition-colors cursor-pointer"
+              :disabled="!apiKey.trim()"
+              @click="handleApiKey"
+            >
+              Authenticate
+            </button>
+          </div>
+        </div>
+
+        <!-- Model selector -->
+        <div>
+          <label class="block text-xs text-[#8b949e] mb-1">Model</label>
+          <select
+            v-model="store.model"
+            class="w-full px-2.5 py-1.5 text-xs rounded bg-[#0d1117] border border-[#30363d] text-[#e0e0e0] outline-none focus:border-[#58a6ff] transition-colors cursor-pointer appearance-none"
+          >
+            <option value="claude-sonnet-4-5-20250514">claude-sonnet-4-5-20250514</option>
+            <option value="claude-opus-4-5-20250414">claude-opus-4-5-20250414</option>
+            <option value="claude-haiku-4-5-20251001">claude-haiku-4-5-20251001</option>
+          </select>
+        </div>
+
+        <!-- Token usage -->
+        <div>
+          <label class="block text-xs text-[#8b949e] mb-1">Token Usage</label>
+          <div class="flex items-center gap-3 text-xs text-[#e0e0e0]">
+            <span>
+              <span class="text-[#8b949e]">In:</span> {{ formatTokens(store.tokenUsage.input) }}
+            </span>
+            <span>
+              <span class="text-[#8b949e]">Out:</span> {{ formatTokens(store.tokenUsage.output) }}
+            </span>
+          </div>
+        </div>
+
+        <!-- Actions -->
+        <div class="space-y-2 pt-2 border-t border-[#30363d]">
+          <button
+            class="w-full px-3 py-1.5 text-xs font-medium text-[#e0e0e0] bg-[#21262d] hover:bg-[#30363d] border border-[#30363d] rounded transition-colors cursor-pointer"
+            @click="handleClearHistory"
+          >
+            Clear History
+          </button>
+          <button
+            v-if="store.isAuthenticated"
+            class="w-full px-3 py-1.5 text-xs font-medium text-[#f85149] bg-[#21262d] hover:bg-[#30363d] border border-[#30363d] rounded transition-colors cursor-pointer"
+            @click="handleDisconnect"
+          >
+            Disconnect
+          </button>
+        </div>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { ref } from "vue";
+import { useCopilotStore } from "@/stores/copilot.store";
+
+const store = useCopilotStore();
+const apiKey = ref("");
+
+const emit = defineEmits<{
+  (e: "close"): void;
+}>();
+
+function handleLogin(): void {
+  // TODO: Wails AIService.StartLogin()
+  store.startLogin();
+  emit("close");
+}
+
+function handleApiKey(): void {
+  if (!apiKey.value.trim()) return;
+  // TODO: Wails AIService.SetApiKey(apiKey)
+  store.isAuthenticated = true;
+  apiKey.value = "";
+  emit("close");
+}
+
+function handleClearHistory(): void {
+  store.clearHistory();
+  emit("close");
+}
+
+function handleDisconnect(): void {
+  store.disconnect();
+  emit("close");
+}
+
+function formatTokens(n: number): string {
+  if (n >= 1000) return (n / 1000).toFixed(1) + "K";
+  return String(n);
+}
+</script>
diff --git a/frontend/src/components/copilot/CopilotToolViz.vue b/frontend/src/components/copilot/CopilotToolViz.vue
new file mode 100644
index 0000000..90a6662
--- /dev/null
+++ b/frontend/src/components/copilot/CopilotToolViz.vue
@@ -0,0 +1,130 @@
+<template>
+  <div
+    class="rounded border overflow-hidden my-2 text-xs"
+    :class="borderClass"
+  >
+    <!-- Tool call header — clickable to expand -->
+    <button
+      class="w-full flex items-center gap-2 px-2.5 py-1.5 bg-[#21262d] hover:bg-[#282e36] transition-colors cursor-pointer text-left"
+      @click="expanded = !expanded"
+    >
+      <!-- Color bar -->
+      <span class="w-0.5 h-4 rounded-full shrink-0" :class="barColorClass" />
+
+      <!-- Status indicator -->
+      <span v-if="toolCall.status === 'pending'" class="shrink-0">
+        <svg class="w-3.5 h-3.5 animate-spin text-[#8b949e]" viewBox="0 0 24 24" fill="none">
+          <circle cx="12" cy="12" r="10" stroke="currentColor" stroke-width="3" class="opacity-25" />
+          <path d="M4 12a8 8 0 018-8" stroke="currentColor" stroke-width="3" stroke-linecap="round" class="opacity-75" />
+        </svg>
+      </span>
+      <span v-else-if="toolCall.status === 'done'" class="shrink-0 text-[#3fb950]">
+        <svg class="w-3.5 h-3.5" viewBox="0 0 16 16" fill="currentColor">
+          <path d="M13.78 4.22a.75.75 0 010 1.06l-7.25 7.25a.75.75 0 01-1.06 0L2.22 9.28a.75.75 0 011.06-1.06L6 10.94l6.72-6.72a.75.75 0 011.06 0z" />
+        </svg>
+      </span>
+      <span v-else class="shrink-0 text-[#f85149]">
+        <svg class="w-3.5 h-3.5" viewBox="0 0 16 16" fill="currentColor">
+          <path d="M3.72 3.72a.75.75 0 011.06 0L8 6.94l3.22-3.22a.75.75 0 111.06 1.06L9.06 8l3.22 3.22a.75.75 0 11-1.06 1.06L8 9.06l-3.22 3.22a.75.75 0 01-1.06-1.06L6.94 8 3.72 4.78a.75.75 0 010-1.06z" />
+        </svg>
+      </span>
+
+      <!-- Icon + summary -->
+      <span class="text-[#e0e0e0] truncate">{{ icon }} {{ summary }}</span>
+
+      <!-- Expand chevron -->
+      <svg
+        class="w-3 h-3 ml-auto shrink-0 text-[#8b949e] transition-transform"
+        :class="{ 'rotate-90': expanded }"
+        viewBox="0 0 16 16"
+        fill="currentColor"
+      >
+        <path d="M6.22 3.22a.75.75 0 011.06 0l4.25 4.25a.75.75 0 010 1.06l-4.25 4.25a.75.75 0 01-1.06-1.06L9.94 8 6.22 4.28a.75.75 0 010-1.06z" />
+      </svg>
+    </button>
+
+    <!-- Expanded details -->
+    <div v-if="expanded" class="border-t border-[#30363d] bg-[#161b22]">
+      <div class="px-2.5 py-2">
+        <div class="text-[10px] text-[#8b949e] mb-1 uppercase tracking-wide">Input</div>
+        <pre class="text-[11px] text-[#e0e0e0] whitespace-pre-wrap break-all font-mono bg-[#0d1117] rounded p-2">{{ formattedInput }}</pre>
+      </div>
+      <div v-if="toolCall.result !== undefined" class="px-2.5 pb-2">
+        <div class="text-[10px] text-[#8b949e] mb-1 uppercase tracking-wide">Result</div>
+        <pre class="text-[11px] text-[#e0e0e0] whitespace-pre-wrap break-all font-mono bg-[#0d1117] rounded p-2">{{ formattedResult }}</pre>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { ref, computed } from "vue";
+import type { ToolCall } from "@/stores/copilot.store";
+
+const props = defineProps<{
+  toolCall: ToolCall;
+}>();
+
+const expanded = ref(false);
+
+/** Border color class based on tool call status. */
+const borderClass = computed(() => {
+  if (props.toolCall.status === "error") return "border-[#f85149]/30";
+  return "border-[#30363d]";
+});
+
+/** Left color bar based on tool type. */
+const barColorClass = computed(() => {
+  const name = props.toolCall.name;
+  if (name.startsWith("terminal_") || name === "terminal_cwd") return "bg-[#3fb950]";
+  if (name.startsWith("sftp_")) return "bg-[#e3b341]";
+  if (name.startsWith("rdp_")) return "bg-[#1f6feb]";
+  return "bg-[#8b949e]";
+});
+
+/** Icon for the tool type. */
+const icon = computed(() => {
+  const name = props.toolCall.name;
+  const icons: Record<string, string> = {
+    terminal_write: "\u27E9",
+    terminal_read: "\u25CE",
+    terminal_cwd: "\u27E9",
+    sftp_read: "\uD83D\uDCC4",
+    sftp_write: "\uD83D\uDCBE",
+    rdp_screenshot: "\uD83D\uDCF8",
+    rdp_click: "\uD83D\uDDB1",
+    rdp_type: "\u2328",
+    list_sessions: "\u2261",
+    connect_session: "\u2192",
+    disconnect_session: "\u2717",
+  };
+  return icons[name] ?? "\u2022";
+});
+
+/** One-line summary of the tool call. */
+const summary = computed(() => {
+  const name = props.toolCall.name;
+  const input = props.toolCall.input;
+
+  if (name === "terminal_write") return `Typed \`${input.text}\` in session ${input.sessionId}`;
+  if (name === "terminal_read") return `Read ${input.lines ?? "?"} lines from session ${input.sessionId}`;
+  if (name === "terminal_cwd") return `Working directory in session ${input.sessionId}`;
+  if (name === "sftp_read") return `Read ${input.path}`;
+  if (name === "sftp_write") return `Wrote ${input.path}`;
+  if (name === "rdp_screenshot") return `Screenshot from session ${input.sessionId}`;
+  if (name === "rdp_click") return `Clicked at (${input.x}, ${input.y})`;
+  if (name === "rdp_type") return `Typed \`${input.text}\``;
+  if (name === "list_sessions") return "List active sessions";
+  if (name === "connect_session") return `Connect to session ${input.sessionId}`;
+  if (name === "disconnect_session") return `Disconnect session ${input.sessionId}`;
+
+  return name;
+});
+
+const formattedInput = computed(() => JSON.stringify(props.toolCall.input, null, 2));
+const formattedResult = computed(() =>
+  props.toolCall.result !== undefined
+    ? JSON.stringify(props.toolCall.result, null, 2)
+    : "",
+);
+</script>
diff --git a/frontend/src/composables/useCopilot.ts b/frontend/src/composables/useCopilot.ts
new file mode 100644
index 0000000..120d3f2
--- /dev/null
+++ b/frontend/src/composables/useCopilot.ts
@@ -0,0 +1,177 @@
+import { useCopilotStore } from "@/stores/copilot.store";
+import type { ToolCall } from "@/stores/copilot.store";
+
+/**
+ * Composable providing mock Wails binding wrappers for the AI copilot.
+ *
+ * All functions simulate Claude-style behavior until real Wails bindings
+ * (AIService.*) are connected.
+ */
+export function useCopilot() {
+  const store = useCopilotStore();
+
+  /** Simulate word-by-word streaming output. */
+  async function mockStream(
+    text: string,
+    onDelta: (word: string) => void,
+  ): Promise<void> {
+    const words = text.split(" ");
+    for (const word of words) {
+      await new Promise((r) => setTimeout(r, 30 + Math.random() * 70));
+      onDelta(word + " ");
+    }
+  }
+
+  /** Simulate a tool call execution with realistic delay. */
+  async function mockToolCall(
+    name: string,
+    _input: Record<string, unknown>,
+  ): Promise<unknown> {
+    await new Promise((r) => setTimeout(r, 500 + Math.random() * 1000));
+
+    if (name === "list_sessions") return [];
+    if (name === "terminal_read") {
+      return {
+        lines: [
+          "$ systemctl status nginx",
+          "● nginx.service - A high performance web server",
+          "   Loaded: loaded (/lib/systemd/system/nginx.service; enabled)",
+          "   Active: active (running) since Mon 2026-03-17 08:30:12 UTC",
+          "   Main PID: 1234 (nginx)",
+          "   Tasks: 5 (limit: 4915)",
+          "   Memory: 12.4M",
+        ],
+      };
+    }
+    if (name === "terminal_write") return { status: "ok" };
+    if (name === "rdp_screenshot") {
+      return { thumbnail: "data:image/jpeg;base64,/9j/4AAQ..." };
+    }
+    if (name === "rdp_click") return { status: "ok" };
+    if (name === "rdp_type") return { status: "ok" };
+    if (name === "sftp_read") return { content: "# example file content" };
+    if (name === "sftp_write") return { bytesWritten: 1024 };
+
+    return { status: "ok" };
+  }
+
+  /**
+   * Process a user message — route to the appropriate mock response.
+   *
+   * Routes:
+   * - "hello"/"hey" -> greeting
+   * - "ssh"/"server"/"check" -> terminal tool calls
+   * - "rdp"/"desktop"/"screen" -> RDP screenshot tool call
+   * - default -> list_sessions assessment
+   */
+  async function processMessage(text: string): Promise<void> {
+    const lower = text.toLowerCase();
+
+    store.isStreaming = true;
+    const assistantMsg = store.createAssistantMessage();
+
+    try {
+      if (/\b(hello|hey|hi)\b/.test(lower)) {
+        await mockStream(
+          "XO online. I have access to your active sessions. What's the mission, Commander?",
+          (word) => store.appendStreamDelta(word),
+        );
+      } else if (/\b(ssh|server|check|nginx|status)\b/.test(lower)) {
+        await mockStream(
+          "On it. Let me check the server status.",
+          (word) => store.appendStreamDelta(word),
+        );
+
+        // Tool call 1: terminal_write
+        const writeCallId = `tc-${Date.now()}-1`;
+        const writeCall: ToolCall = {
+          id: writeCallId,
+          name: "terminal_write",
+          input: { sessionId: "s1", text: "systemctl status nginx" },
+          status: "pending",
+        };
+        store.addToolCall(writeCall);
+
+        const writeResult = await mockToolCall("terminal_write", writeCall.input);
+        store.completeToolCall(writeCallId, writeResult);
+
+        // Tool call 2: terminal_read
+        const readCallId = `tc-${Date.now()}-2`;
+        const readCall: ToolCall = {
+          id: readCallId,
+          name: "terminal_read",
+          input: { sessionId: "s1", lines: 20 },
+          status: "pending",
+        };
+        store.addToolCall(readCall);
+
+        const readResult = await mockToolCall("terminal_read", readCall.input);
+        store.completeToolCall(readCallId, readResult);
+
+        // Summary
+        store.appendStreamDelta("\n\n");
+        await mockStream(
+          "Nginx is **active and running**. The service has been up since 08:30 UTC today, using 12.4M of memory with 5 active tasks. Everything looks healthy.",
+          (word) => store.appendStreamDelta(word),
+        );
+      } else if (/\b(rdp|desktop|screen|screenshot)\b/.test(lower)) {
+        await mockStream(
+          "Taking a screenshot of the remote desktop.",
+          (word) => store.appendStreamDelta(word),
+        );
+
+        // Tool call: rdp_screenshot
+        const callId = `tc-${Date.now()}`;
+        const call: ToolCall = {
+          id: callId,
+          name: "rdp_screenshot",
+          input: { sessionId: "s2" },
+          status: "pending",
+        };
+        store.addToolCall(call);
+
+        const result = await mockToolCall("rdp_screenshot", call.input);
+        store.completeToolCall(callId, result);
+
+        store.appendStreamDelta("\n\n");
+        await mockStream(
+          "I can see the Windows desktop. The screen shows the default wallpaper with a few application shortcuts. No error dialogs or unusual activity detected.",
+          (word) => store.appendStreamDelta(word),
+        );
+      } else {
+        await mockStream(
+          "Understood. Let me assess the situation.",
+          (word) => store.appendStreamDelta(word),
+        );
+
+        // Tool call: list_sessions
+        const callId = `tc-${Date.now()}`;
+        const call: ToolCall = {
+          id: callId,
+          name: "list_sessions",
+          input: {},
+          status: "pending",
+        };
+        store.addToolCall(call);
+
+        const result = await mockToolCall("list_sessions", call.input);
+        store.completeToolCall(callId, result);
+
+        store.appendStreamDelta("\n\n");
+        await mockStream(
+          "I've reviewed your current sessions. No active connections detected at the moment. Would you like me to connect to a specific server or run a diagnostic?",
+          (word) => store.appendStreamDelta(word),
+        );
+      }
+
+      // Track mock output tokens
+      store.tokenUsage.output += Math.ceil(
+        (assistantMsg.content.length) / 4,
+      );
+    } finally {
+      store.isStreaming = false;
+    }
+  }
+
+  return { mockStream, mockToolCall, processMessage };
+}
diff --git a/frontend/src/layouts/MainLayout.vue b/frontend/src/layouts/MainLayout.vue
index f5e4f7e..837ad6c 100644
--- a/frontend/src/layouts/MainLayout.vue
+++ b/frontend/src/layouts/MainLayout.vue
@@ -31,6 +31,25 @@
             <path d="M11.5 7a4.5 4.5 0 1 1-9 0 4.5 4.5 0 0 1 9 0zm-.82 4.74a6 6 0 1 1 1.06-1.06l3.04 3.04a.75.75 0 1 1-1.06 1.06l-3.04-3.04z" />
           </svg>
         </button>
+        <!-- XO Copilot toggle -->
+        <button
+          class="relative hover:text-[var(--wraith-text-primary)] transition-colors cursor-pointer"
+          :class="copilotStore.isPanelOpen ? 'text-[var(--wraith-accent-blue)]' : ''"
+          title="Toggle XO Copilot (Ctrl+Shift+K)"
+          @click="copilotStore.togglePanel()"
+        >
+          <span class="text-sm">&#x1F47B;</span>
+          <!-- Streaming indicator dot -->
+          <span
+            v-if="copilotStore.isStreaming"
+            class="absolute -top-0.5 -right-0.5 w-1.5 h-1.5 rounded-full bg-[var(--wraith-accent-blue)] animate-pulse"
+          />
+          <!-- Subtle glow when open -->
+          <span
+            v-if="copilotStore.isPanelOpen"
+            class="absolute inset-0 rounded-full bg-[var(--wraith-accent-blue)] opacity-15 blur-sm"
+          />
+        </button>
         <button
           class="hover:text-[var(--wraith-text-primary)] transition-colors cursor-pointer"
           title="Lock vault"
@@ -107,6 +126,11 @@
         <!-- Session area -->
         <SessionContainer />
       </div>
+
+      <!-- Copilot Panel (slides in from right) -->
+      <transition name="copilot-slide">
+        <CopilotPanel v-if="copilotStore.isPanelOpen" />
+      </transition>
     </div>
 
     <!-- Status bar -->
@@ -128,6 +152,7 @@ import { ref, onMounted, onUnmounted } from "vue";
 import { useAppStore } from "@/stores/app.store";
 import { useConnectionStore } from "@/stores/connection.store";
 import { useSessionStore } from "@/stores/session.store";
+import { useCopilotStore } from "@/stores/copilot.store";
 import SidebarToggle from "@/components/sidebar/SidebarToggle.vue";
 import ConnectionTree from "@/components/sidebar/ConnectionTree.vue";
 import FileTree from "@/components/sftp/FileTree.vue";
@@ -139,6 +164,7 @@ import EditorWindow from "@/components/editor/EditorWindow.vue";
 import CommandPalette from "@/components/common/CommandPalette.vue";
 import ThemePicker from "@/components/common/ThemePicker.vue";
 import ImportDialog from "@/components/common/ImportDialog.vue";
+import CopilotPanel from "@/components/copilot/CopilotPanel.vue";
 import type { ThemeDefinition } from "@/components/common/ThemePicker.vue";
 import type { SidebarTab } from "@/components/sidebar/SidebarToggle.vue";
 import type { FileEntry } from "@/composables/useSftp";
@@ -146,6 +172,7 @@ import type { FileEntry } from "@/composables/useSftp";
 const appStore = useAppStore();
 const connectionStore = useConnectionStore();
 const sessionStore = useSessionStore();
+const copilotStore = useCopilotStore();
 
 const sidebarWidth = ref(240);
 const sidebarTab = ref<SidebarTab>("connections");
@@ -247,6 +274,13 @@ function handleQuickConnect(): void {
 
 /** Global keyboard shortcut handler. */
 function handleKeydown(event: KeyboardEvent): void {
+  // Ctrl+Shift+K or Cmd+Shift+K — toggle copilot panel
+  if ((event.ctrlKey || event.metaKey) && event.shiftKey && event.key === "K") {
+    event.preventDefault();
+    copilotStore.togglePanel();
+    return;
+  }
+
   // Ctrl+K or Cmd+K — open command palette
   if ((event.ctrlKey || event.metaKey) && event.key === "k") {
     event.preventDefault();
@@ -262,3 +296,17 @@ onUnmounted(() => {
   document.removeEventListener("keydown", handleKeydown);
 });
 </script>
+
+<style scoped>
+.copilot-slide-enter-active,
+.copilot-slide-leave-active {
+  transition: width 0.3s ease, opacity 0.3s ease;
+  overflow: hidden;
+}
+
+.copilot-slide-enter-from,
+.copilot-slide-leave-to {
+  width: 0px !important;
+  opacity: 0;
+}
+</style>
diff --git a/frontend/src/stores/copilot.store.ts b/frontend/src/stores/copilot.store.ts
new file mode 100644
index 0000000..0272e7f
--- /dev/null
+++ b/frontend/src/stores/copilot.store.ts
@@ -0,0 +1,182 @@
+import { defineStore } from "pinia";
+import { ref } from "vue";
+
+export interface ToolCall {
+  id: string;
+  name: string;
+  input: Record<string, unknown>;
+  result?: unknown;
+  status: "pending" | "done" | "error";
+}
+
+export interface Message {
+  id: string;
+  role: "user" | "assistant";
+  content: string;
+  toolCalls?: ToolCall[];
+  timestamp: number;
+}
+
+export interface ConversationSummary {
+  id: string;
+  title: string;
+  model: string;
+  createdAt: string;
+  tokensIn: number;
+  tokensOut: number;
+}
+
+/**
+ * Copilot (XO) store.
+ * Manages the AI assistant panel state, messages, and streaming.
+ *
+ * All Wails AIService calls are TODOs with mock behavior for now.
+ */
+export const useCopilotStore = defineStore("copilot", () => {
+  const isPanelOpen = ref(false);
+  const isAuthenticated = ref(true); // default true for mock
+  const isStreaming = ref(false);
+  const activeConversationId = ref<string | null>(null);
+  const messages = ref<Message[]>([]);
+  const conversations = ref<ConversationSummary[]>([]);
+  const model = ref("claude-sonnet-4-5-20250514");
+  const tokenUsage = ref({ input: 0, output: 0 });
+  const showSettings = ref(false);
+
+  /** Toggle the copilot panel open/closed. */
+  function togglePanel(): void {
+    isPanelOpen.value = !isPanelOpen.value;
+  }
+
+  /** Start OAuth login flow. */
+  function startLogin(): void {
+    // TODO: Wails AIService.StartLogin()
+    isAuthenticated.value = true;
+  }
+
+  /** Start a new conversation. */
+  function newConversation(): void {
+    // TODO: Wails AIService.NewConversation()
+    activeConversationId.value = `conv-${Date.now()}`;
+    messages.value = [];
+    tokenUsage.value = { input: 0, output: 0 };
+  }
+
+  /** Send a user message and trigger a mock XO response. */
+  function sendMessage(text: string): void {
+    const userMsg: Message = {
+      id: `msg-${Date.now()}`,
+      role: "user",
+      content: text,
+      timestamp: Date.now(),
+    };
+    messages.value.push(userMsg);
+
+    // Track mock input tokens
+    tokenUsage.value.input += Math.ceil(text.length / 4);
+
+    if (!activeConversationId.value) {
+      activeConversationId.value = `conv-${Date.now()}`;
+    }
+  }
+
+  /** Append a streaming text delta to the latest assistant message. */
+  function appendStreamDelta(text: string): void {
+    const last = messages.value[messages.value.length - 1];
+    if (last && last.role === "assistant") {
+      last.content += text;
+    }
+  }
+
+  /** Create a new assistant message (for streaming start). */
+  function createAssistantMessage(): Message {
+    const msg: Message = {
+      id: `msg-${Date.now()}`,
+      role: "assistant",
+      content: "",
+      toolCalls: [],
+      timestamp: Date.now(),
+    };
+    messages.value.push(msg);
+    return msg;
+  }
+
+  /** Add a tool call to the latest assistant message. */
+  function addToolCall(call: ToolCall): void {
+    const last = messages.value[messages.value.length - 1];
+    if (last && last.role === "assistant") {
+      if (!last.toolCalls) last.toolCalls = [];
+      last.toolCalls.push(call);
+    }
+  }
+
+  /** Complete a pending tool call with a result. */
+  function completeToolCall(callId: string, result: unknown): void {
+    for (const msg of messages.value) {
+      if (!msg.toolCalls) continue;
+      const tc = msg.toolCalls.find((t) => t.id === callId);
+      if (tc) {
+        tc.result = result;
+        tc.status = "done";
+        break;
+      }
+    }
+  }
+
+  /** Mark a tool call as errored. */
+  function failToolCall(callId: string, error: unknown): void {
+    for (const msg of messages.value) {
+      if (!msg.toolCalls) continue;
+      const tc = msg.toolCalls.find((t) => t.id === callId);
+      if (tc) {
+        tc.result = error;
+        tc.status = "error";
+        break;
+      }
+    }
+  }
+
+  /** Load conversation list from backend. */
+  async function loadConversations(): Promise<void> {
+    // TODO: Wails AIService.ListConversations()
+    conversations.value = [];
+  }
+
+  /** Clear all messages in the current conversation. */
+  function clearHistory(): void {
+    messages.value = [];
+    activeConversationId.value = null;
+    tokenUsage.value = { input: 0, output: 0 };
+  }
+
+  /** Disconnect from Claude (reset auth state). */
+  function disconnect(): void {
+    // TODO: Wails AIService.Disconnect()
+    isAuthenticated.value = false;
+    clearHistory();
+  }
+
+  return {
+    isPanelOpen,
+    isAuthenticated,
+    isStreaming,
+    activeConversationId,
+    messages,
+    conversations,
+    model,
+    tokenUsage,
+    showSettings,
+    togglePanel,
+    startLogin,
+    newConversation,
+    sendMessage,
+    appendStreamDelta,
+    createAssistantMessage,
+    addToolCall,
+    completeToolCall,
+    failToolCall,
+    loadConversations,
+    clearHistory,
+    disconnect,
+  };
+});