diff --git a/web/hwlab-cloud-web/src/components/layout/AppShell.vue b/web/hwlab-cloud-web/src/components/layout/AppShell.vue
index 6f373937..475a10e4 100644
--- a/web/hwlab-cloud-web/src/components/layout/AppShell.vue
+++ b/web/hwlab-cloud-web/src/components/layout/AppShell.vue
@@ -10,16 +10,22 @@ const auth = useAuthStore();
 const app = useAppStore();
 
 const navSections = [
-  { title: "工作台", items: [{ name: "CodeWorkbench", label: "Code", path: "/workbench" }, { name: "Dashboard", label: "概览", path: "/dashboard" }] },
-  { title: "用户", items: [{ name: "ApiKeys", label: "API Keys", path: "/api-keys" }, { name: "Usage", label: "用量", path: "/usage" }, { name: "Billing", label: "充值", path: "/billing" }] },
-  { title: "管理", items: [{ name: "Access", label: "授权", path: "/admin/access" }, { name: "Users", label: "用户", path: "/admin/users" }, { name: "AdminBilling", label: "账务", path: "/admin/billing" }, { name: "HwpodGroups", label: "HWPOD", path: "/admin/hwpod-groups" }, { name: "ProviderProfiles", label: "Profiles", path: "/admin/provider-profiles" }] },
-  { title: "系统", items: [{ name: "Gate", label: "Gate", path: "/gate" }, { name: "Performance", label: "性能", path: "/performance" }, { name: "Skills", label: "Skills", path: "/skills" }, { name: "Settings", label: "设置", path: "/settings" }, { name: "Help", label: "帮助", path: "/help" }] }
+  { title: "工作台", items: [{ name: "CodeWorkbench", label: "Code", path: "/workbench", icon: "C" }, { name: "Dashboard", label: "概览", path: "/dashboard", icon: "D" }] },
+  { title: "用户", items: [{ name: "ApiKeys", label: "API Keys", path: "/api-keys", icon: "K" }, { name: "Usage", label: "用量", path: "/usage", icon: "U" }, { name: "Billing", label: "充值", path: "/billing", icon: "$" }] },
+  { title: "管理", items: [{ name: "Access", label: "授权", path: "/admin/access", icon: "A" }, { name: "Users", label: "用户", path: "/admin/users", icon: "P" }, { name: "AdminBilling", label: "账务", path: "/admin/billing", icon: "B" }, { name: "HwpodGroups", label: "HWPOD", path: "/admin/hwpod-groups", icon: "H" }, { name: "ProviderProfiles", label: "Profiles", path: "/admin/provider-profiles", icon: "R" }] },
+  { title: "系统", items: [{ name: "Gate", label: "Gate", path: "/gate", icon: "G" }, { name: "Performance", label: "性能", path: "/performance", icon: "M" }, { name: "Skills", label: "Skills", path: "/skills", icon: "S" }, { name: "Settings", label: "设置", path: "/settings", icon: "T" }, { name: "Help", label: "帮助", path: "/help", icon: "?" }] }
 ];
 
 const shellless = computed(() => route.name === "Login" || route.name === "Register" || route.name === "NotFound");
 
-function go(path: string): void {
-  void router.push(path);
+async function go(path: string): Promise<void> {
+  if (route.path === path) return;
+  app.setLoading(true);
+  try {
+    await router.push(path);
+  } finally {
+    window.setTimeout(() => app.setLoading(false), 120);
+  }
 }
 </script>
 
@@ -27,7 +33,7 @@ function go(path: string): void {
   <main v-if="shellless" class="auth-main">
     <slot />
   </main>
-  <main v-else class="platform-shell">
+  <main v-else class="platform-shell" :class="{ 'is-sidebar-collapsed': app.sidebarCollapsed }">
     <aside class="platform-sidebar" :data-collapsed="app.sidebarCollapsed">
       <div class="brand-lockup">
         <span class="brand-mark">HW</span>
@@ -39,9 +45,9 @@ function go(path: string): void {
       <nav class="nav-groups" aria-label="主导航">
         <section v-for="section in navSections" :key="section.title" class="nav-section">
           <h2>{{ section.title }}</h2>
-          <button v-for="item in section.items" :key="item.name" class="nav-item" :data-active="route.name === item.name" type="button" @click="go(item.path)">
-            <span class="nav-dot" />
-            <span>{{ item.label }}</span>
+          <button v-for="item in section.items" :key="item.name" class="nav-item" :data-active="route.name === item.name" type="button" :title="item.label" :aria-label="item.label" @click="go(item.path)">
+            <span class="nav-icon" aria-hidden="true">{{ item.icon }}</span>
+            <span class="nav-label">{{ item.label }}</span>
           </button>
         </section>
       </nav>
@@ -50,6 +56,7 @@ function go(path: string): void {
       <header class="platform-topbar">
         <button class="icon-button" type="button" aria-label="折叠侧边栏" @click="app.sidebarCollapsed = !app.sidebarCollapsed">☰</button>
         <div class="topbar-status">
+          <span v-if="app.loading" class="topbar-progress" aria-live="polite"><span aria-hidden="true" /></span>
           <span>同源 API</span>
           <strong>{{ auth.user?.displayName || auth.user?.username || auth.user?.name || "HWLAB 用户" }}</strong>
         </div>
diff --git a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
index 898e4f52..89510455 100644
--- a/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
+++ b/web/hwlab-cloud-web/src/components/workbench/ConversationPanel.vue
@@ -1,4 +1,5 @@
 <script setup lang="ts">
+import { computed, ref } from "vue";
 import type { ChatMessage } from "@/types";
 import StatusBadge from "@/components/common/StatusBadge.vue";
 import TraceTimeline from "@/components/agent/TraceTimeline.vue";
@@ -11,6 +12,12 @@ import { traceIdentityText } from "./message-rendering";
 
 const workbench = useWorkbenchStore();
 const clipboard = useClipboard();
+const detailMessageId = ref<string | null>(null);
+const detailMessage = computed(() => workbench.messages.find((message) => message.id === detailMessageId.value) ?? null);
+
+function openDetails(message: ChatMessage): void {
+  detailMessageId.value = message.id;
+}
 </script>
 
 <template>
@@ -18,22 +25,36 @@ const clipboard = useClipboard();
     <article v-for="message in workbench.messages" :key="message.id" class="message-card" :data-role="message.role" :data-status="message.status">
       <header>
         <strong>{{ message.title }}</strong>
-        <StatusBadge :status="message.status" />
+        <div class="message-header-actions">
+          <StatusBadge :status="message.status" />
+          <button v-if="message.role === 'agent'" class="message-detail-button" type="button" aria-label="消息详情" title="消息详情" @click="openDetails(message)">i</button>
+        </div>
       </header>
       <MessageMarkdown class="message-text" :source="message.text" />
-      <TraceTimeline :trace="message.runnerTrace" />
-      <CodeAgentStatusSummary :message="message" />
-      <MessageActions
-        :message="message"
-        @cancel="workbench.cancelAgentMessage"
-        @retry="workbench.retryAgentMessage"
-        @replay-trace="workbench.replayAgentTrace"
-        @copy-trace="(target: ChatMessage) => clipboard.copy(traceIdentityText(target))"
-      />
     </article>
     <article v-if="workbench.messages.length === 0" class="message-card empty-message">
       <header><strong>等待会话</strong><StatusBadge status="source" label="SOURCE" /></header>
       <MessageMarkdown class="message-text" source="请先显式新建或选择 session。Code Agent 不会自动滚动新 session 掩盖失败。" />
     </article>
+    <div v-if="detailMessage" class="workbench-dialog-backdrop" role="presentation" @click.self="detailMessageId = null">
+      <section id="message-detail-dialog" class="workbench-dialog wide" role="dialog" aria-modal="true" aria-labelledby="message-detail-title">
+        <header>
+          <div class="dialog-title-stack">
+            <h2 id="message-detail-title">消息详情</h2>
+            <p>{{ detailMessage.traceId || detailMessage.runnerTrace?.traceId || 'trace 未观测' }}</p>
+          </div>
+          <button type="button" class="dialog-close" aria-label="关闭" @click="detailMessageId = null">x</button>
+        </header>
+        <TraceTimeline :trace="detailMessage.runnerTrace" />
+        <CodeAgentStatusSummary :message="detailMessage" />
+        <MessageActions
+          :message="detailMessage"
+          @cancel="workbench.cancelAgentMessage"
+          @retry="workbench.retryAgentMessage"
+          @replay-trace="workbench.replayAgentTrace"
+          @copy-trace="(target: ChatMessage) => clipboard.copy(traceIdentityText(target))"
+        />
+      </section>
+    </div>
   </section>
 </template>
diff --git a/web/hwlab-cloud-web/src/stores/workbench.ts b/web/hwlab-cloud-web/src/stores/workbench.ts
index 97eb382b..f11ed2dd 100644
--- a/web/hwlab-cloud-web/src/stores/workbench.ts
+++ b/web/hwlab-cloud-web/src/stores/workbench.ts
@@ -21,13 +21,14 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   const gatewayShellTimeoutMs = ref(readNumber("hwlab.workbench.gatewayShellTimeoutMs.v1", DEFAULT_GATEWAY_TIMEOUT_MS));
   const live = ref<LiveSurface | null>(null);
   const loading = ref(false);
+  const switchingConversationId = ref<string | null>(null);
   const chatPending = ref(false);
   const error = ref<string | null>(null);
   const activityRef = ref({ lastActivityAt: Date.now(), lastActivityIso: new Date().toISOString(), waitingFor: "idle", lastEventLabel: null as string | null });
   const activeAbort = ref<AbortController | null>(null);
   const currentRequest = ref<{ traceId: string; conversationId: string | null; sessionId: string | null; threadId: string | null; status?: string | null } | null>(null);
 
-  const activeConversationId = computed(() => firstNonEmptyString(workspace.value?.selectedConversationId, workspace.value?.workspace?.selectedConversationId, messages.value.find((message) => message.conversationId)?.conversationId));
+  const activeConversationId = computed(() => firstNonEmptyString(switchingConversationId.value, workspace.value?.selectedConversationId, workspace.value?.workspace?.selectedConversationId, messages.value.find((message) => message.conversationId)?.conversationId));
   const selectedSessionId = computed(() => firstNonEmptyString(workspace.value?.selectedAgentSessionId, workspace.value?.workspace?.selectedAgentSessionId, activeConversation.value?.sessionId));
   const selectedThreadId = computed(() => firstNonEmptyString(workspace.value?.workspace?.threadId, activeConversation.value?.threadId));
   const activeConversation = computed(() => conversations.value.find((item) => item.conversationId === activeConversationId.value) ?? null);
@@ -75,7 +76,9 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   async function createSession(): Promise<void> {
     const current = await ensureWorkspace();
     if (!current) return;
+    loading.value = true;
     const response = await api.workbench.selectConversation(current.workspaceId, { projectId: activeProjectId.value, create: true, updatedByClient: "cloud-web-vue" });
+    loading.value = false;
     if (response.ok) {
       workspace.value = response.data?.workspace ?? current;
       messages.value = messagesFromWorkspace(workspace.value);
@@ -87,12 +90,24 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   async function selectConversation(conversation: ConversationRecord): Promise<void> {
     const current = await ensureWorkspace();
     if (!current) return;
+    const previousWorkspace = workspace.value;
+    const previousMessages = messages.value;
     const tabProjectId = conversation.projectId ?? activeProjectId.value;
+    switchingConversationId.value = conversation.conversationId;
+    workspace.value = optimisticWorkspaceSelection(current, conversation, tabProjectId);
+    messages.value = messagesFromConversation(conversation);
+    loading.value = true;
     const response = await api.workbench.selectConversation(current.workspaceId, { projectId: tabProjectId, conversationId: conversation.conversationId, sessionId: conversation.sessionId, threadId: conversation.threadId, updatedByClient: "cloud-web-vue" });
+    loading.value = false;
+    switchingConversationId.value = null;
     if (response.ok) {
       workspace.value = response.data?.workspace ?? current;
       messages.value = messagesFromWorkspace(workspace.value);
       currentRequest.value = null;
+    } else {
+      workspace.value = previousWorkspace;
+      messages.value = previousMessages;
+      error.value = response.error ?? "session switch failed";
     }
   }
 
@@ -314,6 +329,28 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   return { projectId, workspace, conversations, messages, providerProfile, providerOptions, recentDrafts, codeAgentTimeoutMs, gatewayShellTimeoutMs, live, loading, chatPending, error, activeConversationId, selectedSessionId, selectedThreadId, sessionTabs, composer, hydrate, refreshLive, createSession, selectConversation, deleteCurrentSession, refreshConversations, submitMessage, cancelAgentMessage, cancelRunningTrace, retryAgentMessage, replayAgentTrace, setProviderProfile, refreshProviderOptions, pickDraft, clearRecentDrafts, clearConversation, recordActivity };
 });
 
+function optimisticWorkspaceSelection(current: WorkspaceRecord, conversation: ConversationRecord, projectId: string): WorkspaceRecord {
+  return {
+    ...current,
+    projectId,
+    selectedConversationId: conversation.conversationId,
+    selectedAgentSessionId: conversation.sessionId ?? current.selectedAgentSessionId,
+    selectedConversation: conversation,
+    workspace: {
+      ...(current.workspace ?? {}),
+      projectId,
+      selectedConversationId: conversation.conversationId,
+      selectedAgentSessionId: conversation.sessionId ?? current.workspace?.selectedAgentSessionId,
+      threadId: conversation.threadId ?? current.workspace?.threadId,
+      messages: conversation.messages ?? []
+    }
+  };
+}
+
+function messagesFromConversation(conversation: ConversationRecord): ChatMessage[] {
+  return (conversation.messages ?? []).map((message) => ({ ...message, id: message.id ?? nextProtocolId("msg"), title: message.title ?? (message.role === "user" ? "用户" : "Code Agent"), createdAt: message.createdAt ?? new Date().toISOString(), status: message.status ?? "source" }));
+}
+
 function messagesFromWorkspace(workspace: WorkspaceRecord | null): ChatMessage[] {
   const selected = workspace?.selectedConversation?.messages;
   const embedded = workspace?.workspace?.messages;
diff --git a/web/hwlab-cloud-web/src/styles/workbench.css b/web/hwlab-cloud-web/src/styles/workbench.css
index fac45a52..8c926e1e 100644
--- a/web/hwlab-cloud-web/src/styles/workbench.css
+++ b/web/hwlab-cloud-web/src/styles/workbench.css
@@ -1,10 +1,16 @@
 .platform-shell {
   display: grid;
+  height: 100dvh;
   min-height: 100vh;
   grid-template-columns: 248px minmax(0, 1fr);
+  overflow: hidden;
   background: #eef3f8;
 }
 
+.platform-shell.is-sidebar-collapsed {
+  grid-template-columns: 76px minmax(0, 1fr);
+}
+
 .platform-sidebar {
   position: sticky;
   top: 0;
@@ -18,13 +24,17 @@
 }
 
 .platform-sidebar[data-collapsed="true"] {
-  width: 72px;
+  width: auto;
   overflow: hidden;
+  align-items: center;
+  padding-right: 8px;
+  padding-left: 8px;
 }
 
 .platform-main {
   display: grid;
   min-width: 0;
+  min-height: 0;
   grid-template-rows: 58px minmax(0, 1fr);
 }
 
@@ -39,10 +49,17 @@
 }
 
 .platform-content {
+  display: grid;
+  min-height: 0;
   min-width: 0;
+  overflow: hidden;
   padding: 22px;
 }
 
+.platform-content > * {
+  min-height: 0;
+}
+
 .brand-lockup {
   display: flex;
   min-width: 0;
@@ -91,6 +108,18 @@
   gap: 16px;
 }
 
+.route-stack {
+  overflow: auto;
+}
+
+.workbench-route {
+  height: 100%;
+  min-height: 0;
+  grid-template-rows: auto minmax(0, 1fr);
+  gap: 12px;
+  overflow: hidden;
+}
+
 .nav-section h2 {
   margin: 0 0 4px;
   color: #94a3b8;
@@ -113,6 +142,36 @@
   text-align: left;
 }
 
+.nav-icon {
+  display: inline-flex;
+  width: 24px;
+  height: 24px;
+  flex: 0 0 auto;
+  align-items: center;
+  justify-content: center;
+  border-radius: 7px;
+  background: #e2e8f0;
+  color: #334155;
+  font-size: 12px;
+  font-weight: 850;
+}
+
+.nav-item[data-active="true"] .nav-icon {
+  background: #bae6fd;
+  color: #075985;
+}
+
+.platform-sidebar[data-collapsed="true"] .brand-lockup div,
+.platform-sidebar[data-collapsed="true"] .nav-section h2,
+.platform-sidebar[data-collapsed="true"] .nav-label {
+  display: none;
+}
+
+.platform-sidebar[data-collapsed="true"] .nav-item {
+  justify-content: center;
+  padding: 9px;
+}
+
 .nav-item[data-active="true"] {
   background: #e0f2fe;
   color: #0c4a6e;
@@ -139,6 +198,27 @@
   gap: 10px;
 }
 
+.topbar-progress {
+  display: inline-flex;
+  width: 18px;
+  height: 18px;
+  align-items: center;
+  justify-content: center;
+}
+
+.topbar-progress span {
+  width: 14px;
+  height: 14px;
+  border: 2px solid #bae6fd;
+  border-top-color: #0e7490;
+  border-radius: 999px;
+  animation: workbench-spin 0.8s linear infinite;
+}
+
+@keyframes workbench-spin {
+  to { transform: rotate(360deg); }
+}
+
 .auth-main,
 .login-shell {
   display: grid;
@@ -190,22 +270,81 @@
   color: #b91c1c;
 }
 
-.workbench-status-row {
+.workbench-diagnostics-bar {
   display: flex;
-  flex-wrap: wrap;
-  align-items: center;
-  gap: 10px;
-  color: #475569;
-  font-size: 13px;
+  justify-content: flex-end;
+  min-height: 34px;
 }
 
-.workbench-live-strip {
-  display: flex;
-  flex-wrap: wrap;
-  align-items: stretch;
+.workbench-diagnostics-toggle {
+  display: inline-flex;
+  min-height: 34px;
+  align-items: center;
+  gap: 8px;
+  border: 1px solid #cbd5e1;
+  border-radius: 8px;
+  background: white;
+  color: #334155;
+  padding: 4px 8px;
+  font-weight: 800;
+}
+
+.workbench-diagnostics-toggle > span:first-child,
+.message-detail-button {
+  display: inline-flex;
+  width: 22px;
+  height: 22px;
+  align-items: center;
+  justify-content: center;
+  border-radius: 999px;
+  background: #e0f2fe;
+  color: #0c4a6e;
+  font-size: 12px;
+  font-weight: 850;
+}
+
+.workbench-diagnostics-grid {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
   gap: 10px;
 }
 
+.workbench-diagnostics-summary {
+  display: grid;
+  grid-column: 1 / -1;
+  grid-template-columns: repeat(4, minmax(0, 1fr));
+  gap: 8px;
+  margin: 0;
+}
+
+.workbench-diagnostics-summary div {
+  min-width: 0;
+  border: 1px solid #e2e8f0;
+  border-radius: 8px;
+  background: #f8fafc;
+  padding: 8px;
+}
+
+.workbench-diagnostics-summary dt,
+.workbench-diagnostics-summary dd {
+  min-width: 0;
+  margin: 0;
+  overflow-wrap: anywhere;
+}
+
+.workbench-diagnostics-summary dt {
+  color: #64748b;
+  font-size: 11px;
+  font-weight: 800;
+  text-transform: uppercase;
+}
+
+.workbench-diagnostics-summary dd {
+  color: #0f172a;
+  font-size: 12px;
+  font-weight: 750;
+}
+
 .probe-card,
 .live-build-summary {
   min-width: min(320px, 100%);
@@ -373,8 +512,9 @@
 
 .workbench-grid {
   display: grid;
-  min-height: calc(100vh - 180px);
-  grid-template-columns: minmax(220px, 300px) minmax(0, 1fr) minmax(280px, 360px);
+  min-height: 0;
+  height: 100%;
+  grid-template-columns: auto minmax(0, 1fr) minmax(280px, 360px);
   gap: 14px;
 }
 
@@ -393,6 +533,8 @@
 
 .workbench-center {
   display: grid;
+  height: 100%;
+  min-height: 0;
   min-width: 0;
   grid-template-rows: minmax(0, 1fr) auto;
   overflow: hidden;
@@ -402,6 +544,8 @@
 .hwpod-panel {
   position: relative;
   display: grid;
+  height: 100%;
+  min-height: 0;
   min-width: 0;
   align-content: start;
   gap: 12px;
@@ -409,6 +553,14 @@
   overflow: hidden;
 }
 
+.session-rail {
+  grid-template-rows: auto auto minmax(0, 1fr) auto auto;
+}
+
+.hwpod-panel {
+  grid-template-rows: auto auto minmax(0, auto) auto minmax(0, 1fr);
+}
+
 .panel-header {
   display: flex;
   align-items: center;
@@ -424,6 +576,7 @@
 .session-list,
 .conversation-panel {
   display: grid;
+  min-height: 0;
   gap: 10px;
   overflow: auto;
 }
@@ -488,6 +641,19 @@
   gap: 10px;
 }
 
+.message-header-actions {
+  display: inline-flex;
+  flex: 0 0 auto;
+  align-items: center;
+  gap: 8px;
+}
+
+.message-detail-button {
+  border: 0;
+  cursor: pointer;
+  padding: 0;
+}
+
 .message-text,
 .message-markdown {
   margin: 0;
@@ -865,9 +1031,18 @@
 .hwpod-node-status,
 .hwpod-event-panel {
   display: grid;
+  min-height: 0;
   gap: 10px;
 }
 
+.hwpod-node-status {
+  overflow: auto;
+}
+
+.hwpod-event-panel {
+  grid-template-rows: auto minmax(0, 1fr);
+}
+
 .hwpod-node-summary {
   display: grid;
   grid-template-columns: repeat(2, minmax(0, 1fr));
@@ -971,7 +1146,8 @@
 }
 
 .hwpod-event-scroll {
-  max-height: 210px;
+  min-height: 0;
+  max-height: none;
   overflow: auto;
   border: 1px solid #d8e1eb;
   border-radius: 8px;
@@ -1686,7 +1862,7 @@
 
   .platform-sidebar .brand-lockup div,
   .nav-section h2,
-  .nav-item span:not(.nav-dot) {
+  .nav-label {
     display: none;
   }
 
@@ -1701,6 +1877,22 @@
     grid-template-columns: 1fr;
   }
 
+  .workbench-route {
+    height: auto;
+    overflow: auto;
+  }
+
+  .workbench-grid,
+  .session-rail,
+  .workbench-center,
+  .hwpod-panel {
+    height: auto;
+  }
+
+  .hwpod-event-scroll {
+    max-height: 260px;
+  }
+
   .field-grid,
   .form-grid.two-col,
   .compact-form-grid {
@@ -1711,6 +1903,8 @@
 @media (max-width: 720px) {
   .platform-shell {
     grid-template-columns: 1fr;
+    height: auto;
+    overflow: auto;
   }
 
   .platform-sidebar {
@@ -1724,6 +1918,7 @@
 
   .platform-content {
     padding: 14px;
+    overflow: visible;
   }
 
   .platform-topbar {
diff --git a/web/hwlab-cloud-web/src/views/workbench/CodeWorkbenchView.vue b/web/hwlab-cloud-web/src/views/workbench/CodeWorkbenchView.vue
index e0ccd3f1..aa97ec2d 100644
--- a/web/hwlab-cloud-web/src/views/workbench/CodeWorkbenchView.vue
+++ b/web/hwlab-cloud-web/src/views/workbench/CodeWorkbenchView.vue
@@ -1,6 +1,5 @@
 <script setup lang="ts">
-import { onMounted } from "vue";
-import PageHeader from "@/components/common/PageHeader.vue";
+import { onMounted, ref } from "vue";
 import StatusBadge from "@/components/common/StatusBadge.vue";
 import CommandComposer from "@/components/workbench/CommandComposer.vue";
 import ConversationPanel from "@/components/workbench/ConversationPanel.vue";
@@ -12,22 +11,18 @@ import { useAutoRefresh } from "@/composables/useAutoRefresh";
 import { useWorkbenchStore } from "@/stores/workbench";
 
 const workbench = useWorkbenchStore();
+const diagnosticsOpen = ref(false);
 onMounted(() => void workbench.hydrate());
 useAutoRefresh(() => workbench.refreshLive(), 30_000);
 </script>
 
 <template>
   <section id="workspace" class="workbench-route">
-    <PageHeader eyebrow="Workbench" title="Code Workbench" description="Code Agent 是平台控制台中的一个应用页面；session、trace、HWPOD evidence 仍走 Cloud Web 同源 API。" />
-    <div class="workbench-status-row">
-      <StatusBadge :status="workbench.chatPending ? 'running' : 'source'" :label="workbench.chatPending ? '处理中' : 'SOURCE'" />
-      <span>Provider: {{ workbench.providerProfile }}</span>
-      <span>Composer: {{ workbench.composer.submitMode }}{{ workbench.composer.targetTraceId ? ` ${workbench.composer.targetTraceId}` : '' }}</span>
-      <span>Timeout: inactivity {{ Math.round(workbench.codeAgentTimeoutMs / 1000) }}s</span>
-    </div>
-    <div class="workbench-live-strip" aria-label="Workbench live status">
-      <WorkbenchProbePanel :live="workbench.live" />
-      <WorkbenchBuildSummary :live="workbench.live" />
+    <div class="workbench-diagnostics-bar">
+      <button id="workbench-diagnostics-toggle" class="workbench-diagnostics-toggle" type="button" aria-haspopup="dialog" @click="diagnosticsOpen = true">
+        <span aria-hidden="true">i</span>
+        <StatusBadge :status="workbench.chatPending ? 'running' : 'source'" :label="workbench.chatPending ? '处理中' : '诊断'" />
+      </button>
     </div>
     <div class="workbench-grid">
       <SessionRail />
@@ -37,5 +32,26 @@ useAutoRefresh(() => workbench.refreshLive(), 30_000);
       </main>
       <HwpodNodeOpsPanel />
     </div>
+    <div v-if="diagnosticsOpen" class="workbench-dialog-backdrop" role="presentation" @click.self="diagnosticsOpen = false">
+      <section id="workbench-diagnostics-dialog" class="workbench-dialog wide" role="dialog" aria-modal="true" aria-labelledby="workbench-diagnostics-title">
+        <header>
+          <div class="dialog-title-stack">
+            <h2 id="workbench-diagnostics-title">Workbench 诊断</h2>
+            <p>Code Agent session、trace、HWPOD evidence 仍走 Cloud Web 同源 API。</p>
+          </div>
+          <button type="button" class="dialog-close" aria-label="关闭" @click="diagnosticsOpen = false">x</button>
+        </header>
+        <div class="workbench-diagnostics-grid">
+          <dl class="workbench-diagnostics-summary">
+            <div><dt>Provider</dt><dd>{{ workbench.providerProfile }}</dd></div>
+            <div><dt>Composer</dt><dd>{{ workbench.composer.submitMode }}{{ workbench.composer.targetTraceId ? ` ${workbench.composer.targetTraceId}` : '' }}</dd></div>
+            <div><dt>Timeout</dt><dd>inactivity {{ Math.round(workbench.codeAgentTimeoutMs / 1000) }}s</dd></div>
+            <div><dt>Session</dt><dd>{{ workbench.selectedSessionId || '未选择' }}</dd></div>
+          </dl>
+          <WorkbenchProbePanel :live="workbench.live" />
+          <WorkbenchBuildSummary :live="workbench.live" />
+        </div>
+      </section>
+    </div>
   </section>
 </template>