diff --git a/frontend/src/assets/dropdown-menu.less b/frontend/src/assets/dropdown-menu.less
index 4c7ca3e5..61385f08 100644
--- a/frontend/src/assets/dropdown-menu.less
+++ b/frontend/src/assets/dropdown-menu.less
@@ -181,7 +181,38 @@
     padding: 4px;
     min-width: 148px;
     animation: dropdownSlideIn 0.18s cubic-bezier(0.2, 0, 0, 1) both;
-    overflow: hidden;
+    overflow-x: hidden;
+    overflow-y: auto;
+    scrollbar-width: thin;
+    scrollbar-color: transparent transparent;
+    transition: scrollbar-color 0.2s ease;
+
+    &::-webkit-scrollbar {
+      width: 6px;
+    }
+
+    &::-webkit-scrollbar-track {
+      background: transparent;
+    }
+
+    &::-webkit-scrollbar-thumb {
+      background-color: transparent;
+      border: none;
+      border-radius: 6px;
+      transition: background-color 0.2s ease;
+    }
+
+    &:hover {
+      scrollbar-color: var(--td-scrollbar-color, rgba(0, 0, 0, 0.18)) transparent;
+
+      &::-webkit-scrollbar-thumb {
+        background-color: var(--td-scrollbar-color, rgba(0, 0, 0, 0.18));
+      }
+    }
+
+    &::-webkit-scrollbar-thumb:hover {
+      background-color: var(--td-scrollbar-hover-color, rgba(0, 0, 0, 0.32));
+    }
   }
 
   .t-dropdown__item {
@@ -493,5 +524,17 @@
       0 0 0 0.5px rgba(255, 255, 255, 0.05),
       0 2px 4px rgba(0, 0, 0, 0.12),
       0 8px 32px rgba(0, 0, 0, 0.28);
+
+    &:hover {
+      scrollbar-color: rgba(255, 255, 255, 0.22) transparent;
+
+      &::-webkit-scrollbar-thumb {
+        background-color: rgba(255, 255, 255, 0.22);
+      }
+    }
+
+    &::-webkit-scrollbar-thumb:hover {
+      background-color: rgba(255, 255, 255, 0.38);
+    }
   }
 }
diff --git a/frontend/src/components/AgentSelector.vue b/frontend/src/components/AgentSelector.vue
index 4c418111..7848e61a 100644
--- a/frontend/src/components/AgentSelector.vue
+++ b/frontend/src/components/AgentSelector.vue
@@ -1,11 +1,7 @@
 <template>
   <Teleport to="body">
     <div v-if="visible" class="agent-selector-overlay" @click="$emit('close')">
-      <div
-        class="agent-selector-dropdown"
-        :style="dropdownStyle"
-        @click.stop
-      >
+      <div class="agent-selector-dropdown" :style="dropdownStyle" @click.stop>
         <div class="agent-selector-header">
           <span>{{ $t('agent.selectAgent') }}</span>
           <router-link to="/platform/agents" class="agent-selector-add" @click="$emit('close')">
@@ -18,32 +14,22 @@
           <!-- 内置智能体 -->
           <div class="agent-group">
             <div class="agent-group-title">{{ $t('agent.builtinAgents') }}</div>
-            <div
-              v-for="agent in builtinAgents"
-              :key="agent.id"
-              class="agent-option"
-              :class="{ selected: isMyAgentSelected(agent) }"
-              @mouseenter="onOptionEnter(agent, $event)"
-              @mouseleave="onOptionLeave"
-              @click="selectAgent(agent)"
-            >
-              <div
-                v-if="agent.id === BUILTIN_QUICK_ANSWER_ID || agent.id === BUILTIN_SMART_REASONING_ID"
-                class="builtin-icon"
-                :class="agent.config?.agent_mode === 'smart-reasoning' ? 'agent' : 'normal'"
-              >
-                <TIcon :name="agent.config?.agent_mode === 'smart-reasoning' ? 'control-platform' : 'chat'" size="14px" />
+            <div v-for="agent in builtinAgents" :key="agent.id" class="agent-option"
+              :class="{ selected: isMyAgentSelected(agent) }" @mouseenter="onOptionEnter(agent, $event)"
+              @mouseleave="onOptionLeave" @click="selectAgent(agent)">
+              <div v-if="agent.id === BUILTIN_QUICK_ANSWER_ID || agent.id === BUILTIN_SMART_REASONING_ID"
+                class="builtin-icon" :class="agent.config?.agent_mode === 'smart-reasoning' ? 'agent' : 'normal'">
+                <TIcon :name="agent.config?.agent_mode === 'smart-reasoning' ? 'control-platform' : 'chat'"
+                  size="13px" />
               </div>
               <div v-else-if="agent.avatar" class="builtin-avatar">{{ agent.avatar }}</div>
               <div v-else class="builtin-icon normal">
-                <TIcon name="app" size="14px" />
+                <TIcon name="app" size="13px" />
               </div>
               <span class="agent-option-name">{{ agent.name }}</span>
               <div v-if="getAgentNotReadyLabels(agent).length" class="agent-option-actions">
-                <t-tooltip
-                  :content="$t('agent.selector.notReadyHint', { items: formatNotReadyHint(agent) })"
-                  placement="top"
-                >
+                <t-tooltip :content="$t('agent.selector.notReadyHint', { items: formatNotReadyHint(agent) })"
+                  placement="top">
                   <TIcon name="error-circle" size="14px" class="not-ready-icon" @click.stop />
                 </t-tooltip>
               </div>
@@ -53,22 +39,14 @@
           <!-- 自定义智能体 -->
           <div v-if="customAgents.length > 0" class="agent-group">
             <div class="agent-group-title">{{ $t('agent.customAgents') }}</div>
-            <div
-              v-for="agent in customAgents"
-              :key="agent.id"
-              class="agent-option"
-              :class="{ selected: isMyAgentSelected(agent) }"
-              @mouseenter="onOptionEnter(agent, $event)"
-              @mouseleave="onOptionLeave"
-              @click="selectAgent(agent)"
-            >
+            <div v-for="agent in customAgents" :key="agent.id" class="agent-option"
+              :class="{ selected: isMyAgentSelected(agent) }" @mouseenter="onOptionEnter(agent, $event)"
+              @mouseleave="onOptionLeave" @click="selectAgent(agent)">
               <AgentAvatar :name="agent.name" size="small" />
               <span class="agent-option-name">{{ agent.name }}</span>
               <div v-if="getAgentNotReadyLabels(agent).length" class="agent-option-actions">
-                <t-tooltip
-                  :content="$t('agent.selector.notReadyHint', { items: formatNotReadyHint(agent) })"
-                  placement="top"
-                >
+                <t-tooltip :content="$t('agent.selector.notReadyHint', { items: formatNotReadyHint(agent) })"
+                  placement="top">
                   <TIcon name="error-circle" size="14px" class="not-ready-icon" @click.stop />
                 </t-tooltip>
               </div>
@@ -78,36 +56,26 @@
           <!-- 共享给我 -->
           <div v-if="sharedAgentsList.length > 0" class="agent-group">
             <div class="agent-group-title">{{ $t('agent.tabs.sharedToMe') }}</div>
-            <div
-              v-for="shared in sharedAgentsList"
-              :key="`${shared.agent.id}-${shared.source_tenant_id}`"
-              class="agent-option"
-              :class="{ selected: isSharedAgentSelected(shared) }"
-              @mouseenter="onSharedOptionEnter(shared, $event)"
-              @mouseleave="onOptionLeave"
-              @click="selectSharedAgent(shared)"
-            >
+            <div v-for="shared in sharedAgentsList" :key="`${shared.agent.id}-${shared.source_tenant_id}`"
+              class="agent-option" :class="{ selected: isSharedAgentSelected(shared) }"
+              @mouseenter="onSharedOptionEnter(shared, $event)" @mouseleave="onOptionLeave"
+              @click="selectSharedAgent(shared)">
               <AgentAvatar :name="shared.agent.name" size="small" />
               <span class="agent-option-name">{{ shared.agent.name }}</span>
               <span class="shared-tag">{{ $t('agent.selector.sharedLabel') }}</span>
-              <div
-                v-if="getAgentNotReadyLabels(shared.agent, String(shared.source_tenant_id)).length"
-                class="agent-option-actions"
-              >
+              <div v-if="getAgentNotReadyLabels(shared.agent, String(shared.source_tenant_id)).length"
+                class="agent-option-actions">
                 <t-tooltip
                   :content="$t('agent.selector.notReadyHint', { items: formatNotReadyHint(shared.agent, String(shared.source_tenant_id)) })"
-                  placement="top"
-                >
+                  placement="top">
                   <TIcon name="error-circle" size="14px" class="not-ready-icon" @click.stop />
                 </t-tooltip>
               </div>
             </div>
           </div>
 
-          <div
-            v-if="builtinAgents.length === 0 && customAgents.length === 0 && sharedAgentsList.length === 0"
-            class="agent-option empty"
-          >
+          <div v-if="builtinAgents.length === 0 && customAgents.length === 0 && sharedAgentsList.length === 0"
+            class="agent-option empty">
             {{ $t('agent.noAgents') }}
           </div>
         </div>
@@ -115,57 +83,41 @@
     </div>
 
     <!-- 详情浮层 -->
-    <div
-      v-if="visible && activeDetail"
-      class="agent-detail-panel"
-      :style="detailPanelStyle"
-      @mouseenter="onDetailPanelEnter"
-      @mouseleave="onDetailPanelLeave"
-      @click.stop
-    >
+    <div v-if="visible && activeDetail" ref="detailPanelRef" class="agent-detail-panel" :style="detailPanelStyle"
+      @mouseenter="onDetailPanelEnter" @mouseleave="onDetailPanelLeave" @click.stop>
       <div class="agent-detail-panel-inner">
         <div class="agent-detail-content">
           <div class="detail-header">
-            <template v-if="activeDetail.agent.id === BUILTIN_QUICK_ANSWER_ID || activeDetail.agent.id === BUILTIN_SMART_REASONING_ID">
-              <div
-                class="builtin-icon detail-icon"
-                :class="activeDetail.agent.config?.agent_mode === 'smart-reasoning' ? 'agent' : 'normal'"
-              >
-                <TIcon
-                  :name="activeDetail.agent.config?.agent_mode === 'smart-reasoning' ? 'control-platform' : 'chat'"
-                  size="14px"
-                />
+            <template
+              v-if="activeDetail.agent.id === BUILTIN_QUICK_ANSWER_ID || activeDetail.agent.id === BUILTIN_SMART_REASONING_ID">
+              <div class="builtin-icon detail-icon"
+                :class="activeDetail.agent.config?.agent_mode === 'smart-reasoning' ? 'agent' : 'normal'">
+                <TIcon :name="activeDetail.agent.config?.agent_mode === 'smart-reasoning' ? 'control-platform' : 'chat'"
+                  size="14px" />
               </div>
             </template>
-            <div v-else-if="activeDetail.agent.avatar" class="builtin-avatar detail-icon">{{ activeDetail.agent.avatar }}</div>
+            <div v-else-if="activeDetail.agent.avatar" class="builtin-avatar detail-icon">{{ activeDetail.agent.avatar
+              }}</div>
             <AgentAvatar v-else :name="activeDetail.agent.name" size="small" />
             <div class="detail-title-wrap">
               <div class="detail-title-row">
                 <span class="detail-name">{{ activeDetail.agent.name }}</span>
-                <button
-                  type="button"
-                  class="detail-header-action"
-                  :class="{ 'detail-header-action--warn': activeDetailNotReadyLabels.length }"
-                  :title="activeDetailNotReadyLabels.length
+                <button v-if="canShowDetailHeaderAction" type="button" class="detail-header-action"
+                  :class="{ 'detail-header-action--warn': activeDetailNotReadyLabels.length }" :title="activeDetailNotReadyLabels.length
                     ? $t('agent.selector.configureAction')
                     : $t('agent.selector.goToSettings')"
-                  @click="goToSettings(activeDetail.agent, activeDetail.sourceTenantId)"
-                >
-                  <TIcon
-                    :name="activeDetailNotReadyLabels.length ? 'jump' : 'setting'"
-                    size="14px"
-                  />
+                  @click="goToSettings(activeDetail.agent, activeDetail.sourceTenantId)">
+                  <TIcon :name="activeDetailNotReadyLabels.length ? 'jump' : 'setting'" size="14px" />
                 </button>
               </div>
               <span v-if="isDetailCurrent" class="detail-current">{{ $t('agent.selector.current') }}</span>
               <div v-else-if="activeDetailNotReadyLabels.length" class="detail-not-ready">
                 <TIcon name="error-circle" size="13px" class="detail-not-ready-icon" />
                 <span class="detail-not-ready-label">{{ $t('agent.selector.notReadyStatus') }}</span>
-                <span
-                  v-for="item in activeDetailNotReadyLabels"
-                  :key="item"
-                  class="detail-not-ready-item"
-                >{{ item }}</span>
+                <span v-for="item in activeDetailNotReadyLabels" :key="item" class="detail-not-ready-item">{{ item
+                  }}</span>
+                <span v-if="activeDetail.sourceTenantId && activeDetailNotReadyLabels.length"
+                  class="detail-not-ready-shared-hint">{{ $t('agent.selector.sharedNotReadyContact') }}</span>
               </div>
             </div>
           </div>
@@ -174,15 +126,23 @@
 
           <div class="detail-tags">
             <span class="detail-tag">
-              {{ activeDetail.agent.config?.agent_mode === 'smart-reasoning' ? $t('agent.type.agent') : $t('agent.type.normal') }}
+              {{ activeDetail.agent.config?.agent_mode === 'smart-reasoning' ? $t('agent.type.agent') :
+                $t('agent.type.normal') }}
             </span>
-            <span v-if="getKbCapability(activeDetail.agent)" class="detail-tag">{{ getKbCapability(activeDetail.agent) }}</span>
-            <span v-if="activeDetail.agent.config?.web_search_enabled" class="detail-tag">{{ $t('agent.capabilities.webSearchOn') }}</span>
-            <span v-if="getMcpCapability(activeDetail.agent)" class="detail-tag">{{ getMcpCapability(activeDetail.agent) }}</span>
-            <span v-if="activeDetail.agent.config?.multi_turn_enabled" class="detail-tag">{{ $t('agent.capabilities.multiTurn') }}</span>
+            <span v-if="getKbCapability(activeDetail.agent)" class="detail-tag">{{ getKbCapability(activeDetail.agent)
+              }}</span>
+            <span v-if="activeDetail.agent.config?.web_search_enabled" class="detail-tag">{{
+              $t('agent.capabilities.webSearchOn')
+              }}</span>
+            <span v-if="getMcpCapability(activeDetail.agent)" class="detail-tag">{{ getMcpCapability(activeDetail.agent)
+              }}</span>
+            <span v-if="activeDetail.agent.config?.multi_turn_enabled" class="detail-tag">{{
+              $t('agent.capabilities.multiTurn')
+              }}</span>
           </div>
 
-          <div v-if="activeDetail.sharedMeta?.org_name || activeDetail.sharedMeta?.shared_by_username" class="detail-meta">
+          <div v-if="activeDetail.sharedMeta?.org_name || activeDetail.sharedMeta?.shared_by_username"
+            class="detail-meta">
             <div v-if="activeDetail.sharedMeta.org_name" class="detail-meta-row">
               <img src="@/assets/img/organization-green.svg" class="detail-meta-icon" alt="" aria-hidden="true" />
               <span>{{ activeDetail.sharedMeta.org_name }}</span>
@@ -214,6 +174,7 @@ import {
   getAgentNotReadyReasonKeys,
   resolveAgentNotReadySection,
   resolveAgentNotReadyHighlight,
+  canLocallyConfigureAgent,
   type AgentNotReadyReasonKey,
 } from '@/utils/agent-readiness';
 import { formatLocalizedList } from '@/utils/format-list';
@@ -246,9 +207,14 @@ type AgentDetailTarget = {
 const dropdownStyle = ref<Record<string, string>>({});
 const activeDetail = ref<AgentDetailTarget | null>(null);
 const detailAnchorEl = ref<HTMLElement | null>(null);
+const detailPanelRef = ref<HTMLElement | null>(null);
 const detailPanelStyle = ref<Record<string, string>>({});
 let detailHideTimer: ReturnType<typeof setTimeout> | null = null;
 
+const DETAIL_PANEL_WIDTH = 200;
+const DETAIL_BRIDGE_OVERLAP = 10;
+const DETAIL_HIDE_DELAY_MS = 400;
+
 const agentsList = computed(() => props.agents ?? []);
 
 const builtinAgents = computed(() => {
@@ -294,6 +260,13 @@ const activeDetailNotReadyLabels = computed(() => {
   return getAgentNotReadyLabels(detail.agent, detail.sourceTenantId);
 });
 
+const canShowDetailHeaderAction = computed(() => {
+  const detail = activeDetail.value;
+  if (!detail) return false;
+  if (canLocallyConfigureAgent(detail.sourceTenantId)) return true;
+  return activeDetailNotReadyLabels.value.length === 0;
+});
+
 const getKbCapability = (agent: CustomAgent): string => {
   const config = agent.config || {};
   if (config.kb_selection_mode === 'none') return '';
@@ -371,34 +344,54 @@ const updateDetailPanelPosition = () => {
   if (!el || !activeDetail.value) return;
 
   const zoom = getRootZoom();
-  const rect = rectToCssPx(el.getBoundingClientRect(), zoom);
+  const rowRect = rectToCssPx(el.getBoundingClientRect(), zoom);
   const { width: vw, height: vh } = cssViewportSize(zoom);
-  const panelWidth = 200;
-  const gap = 6;
-  let left = rect.right + gap;
-  let top = rect.top;
 
-  if (left + panelWidth > vw - 8) {
-    left = Math.max(8, vw - panelWidth - 8);
+  // 向左重叠一段透明区域，避免鼠标从选项移向浮层时经过空隙触发 mouseleave
+  let left = rowRect.right - DETAIL_BRIDGE_OVERLAP;
+  if (left + DETAIL_PANEL_WIDTH > vw - 8) {
+    left = Math.max(8, vw - DETAIL_PANEL_WIDTH - 8);
   }
-  if (top + 240 > vh - 8) {
-    top = Math.max(8, vh - 248);
+
+  const panelHeight = detailPanelRef.value?.offsetHeight || 180;
+  const rowCenter = rowRect.top + rowRect.height / 2;
+  let top = rowCenter - panelHeight / 2;
+
+  const minTop = 8;
+  const maxTop = vh - panelHeight - 8;
+  if (top < minTop) {
+    top = minTop;
+  } else if (top > maxTop) {
+    // 贴近当前行：优先让浮层与 hover 行在垂直方向仍有交集
+    top = Math.min(rowRect.top, maxTop);
+    top = Math.max(minTop, Math.min(top, rowRect.bottom - panelHeight));
+    if (top + panelHeight < rowRect.top) {
+      top = rowRect.top;
+    }
+    top = Math.max(minTop, Math.min(top, maxTop));
   }
 
   detailPanelStyle.value = {
     position: 'fixed',
     left: `${Math.round(left)}px`,
     top: `${Math.round(top)}px`,
-    width: `${panelWidth}px`,
+    width: `${DETAIL_PANEL_WIDTH}px`,
     zIndex: '10002',
   };
 };
 
+const scheduleDetailPanelPosition = () => {
+  nextTick(() => {
+    updateDetailPanelPosition();
+    requestAnimationFrame(() => updateDetailPanelPosition());
+  });
+};
+
 const onOptionEnter = (agent: CustomAgent, event: MouseEvent, sourceTenantId?: string, sharedMeta?: AgentDetailTarget['sharedMeta']) => {
   clearDetailHideTimer();
   detailAnchorEl.value = event.currentTarget as HTMLElement;
   activeDetail.value = { agent, sourceTenantId, sharedMeta };
-  nextTick(() => updateDetailPanelPosition());
+  scheduleDetailPanelPosition();
 };
 
 const onSharedOptionEnter = (shared: SharedAgentInfo, event: MouseEvent) => {
@@ -412,7 +405,7 @@ const onOptionLeave = () => {
   detailHideTimer = setTimeout(() => {
     activeDetail.value = null;
     detailAnchorEl.value = null;
-  }, 300);
+  }, DETAIL_HIDE_DELAY_MS);
 };
 
 const onDetailPanelEnter = () => {
@@ -447,6 +440,9 @@ const selectSharedAgent = (shared: SharedAgentInfo) => {
 };
 
 const goToSettings = (agent: CustomAgent, sourceTenantId?: string) => {
+  if (!canLocallyConfigureAgent(sourceTenantId) && getAgentNotReadyLabels(agent, sourceTenantId).length > 0) {
+    return;
+  }
   const reasonKeys = getAgentNotReadyReasonKeysFor(agent, sourceTenantId);
   const section = reasonKeys.length > 0 ? resolveAgentNotReadySection(reasonKeys) : 'basic';
   const highlight = resolveAgentNotReadyHighlight(reasonKeys);
@@ -470,15 +466,15 @@ const updateDropdownPosition = () => {
   const rect = rectToCssPx(props.anchorEl.getBoundingClientRect(), zoom);
   const { width: vw, height: vh } = cssViewportSize(zoom);
 
-  const dropdownWidth = 240;
-  const offsetY = 8;
+  const dropdownWidth = 196;
+  const offsetY = 6;
 
   let left = Math.floor(rect.left);
   const minLeft = 16;
   const maxLeft = Math.max(16, vw - dropdownWidth - 16);
   left = Math.max(minLeft, Math.min(maxLeft, left));
 
-  const preferredDropdownHeight = 320;
+  const preferredDropdownHeight = 280;
   const minDropdownHeight = 100;
   const topMargin = 20;
   const spaceBelow = vh - rect.bottom;
@@ -520,6 +516,12 @@ watch(() => props.visible, (newVal) => {
     hideDetailPanel();
   }
 });
+
+watch(activeDetail, (detail) => {
+  if (detail) {
+    scheduleDetailPanelPosition();
+  }
+});
 </script>
 
 <style scoped lang="less">
@@ -542,7 +544,7 @@ watch(() => props.visible, (newVal) => {
   position: fixed !important;
   background: var(--td-bg-color-container);
   border: .5px solid var(--td-component-border);
-  border-radius: 10px;
+  border-radius: 8px;
   box-shadow: var(--td-shadow-2);
   display: flex;
   flex-direction: column;
@@ -553,32 +555,45 @@ watch(() => props.visible, (newVal) => {
 }
 
 @keyframes agentSelectorFadeIn {
-  from { opacity: 0; transform: scale(0.98); }
-  to { opacity: 1; transform: scale(1); }
+  from {
+    opacity: 0;
+    transform: scale(0.98);
+  }
+
+  to {
+    opacity: 1;
+    transform: scale(1);
+  }
 }
 
 .agent-selector-header {
   display: flex;
   align-items: center;
   justify-content: space-between;
-  padding: 8px 10px;
+  gap: 8px;
+  min-height: 32px;
+  padding: 0 8px;
   border-bottom: .5px solid var(--td-component-stroke);
   font-size: 12px;
   font-weight: 500;
+  line-height: 1;
   color: var(--td-text-color-secondary);
 }
 
 .agent-selector-add {
   display: inline-flex;
   align-items: center;
-  gap: 4px;
-  padding: 2px 8px;
-  border-radius: 6px;
+  gap: 2px;
+  height: 22px;
+  padding: 0 6px;
+  border-radius: 5px;
   color: var(--td-brand-color);
   font-size: 12px;
   font-weight: 500;
+  line-height: 1;
   cursor: pointer;
   text-decoration: none;
+  flex-shrink: 0;
 
   &:hover {
     background: var(--td-bg-color-secondarycontainer);
@@ -591,13 +606,13 @@ watch(() => props.visible, (newVal) => {
   overflow-y: auto;
   overscroll-behavior: contain;
   -webkit-overflow-scrolling: touch;
-  padding: 6px 8px;
+  padding: 4px 0;
 }
 
 .agent-group {
   &:not(:last-child) {
-    margin-bottom: 6px;
-    padding-bottom: 6px;
+    margin-bottom: 4px;
+    padding-bottom: 4px;
     border-bottom: .5px solid var(--td-component-stroke);
   }
 }
@@ -605,23 +620,20 @@ watch(() => props.visible, (newVal) => {
 .agent-group-title {
   font-size: 11px;
   color: var(--td-text-color-placeholder);
-  padding: 4px 8px 6px;
+  padding: 6px 8px 4px;
   font-weight: 600;
+  line-height: 16px;
 }
 
 .agent-option {
   display: flex;
   align-items: center;
   gap: 8px;
-  padding: 6px 8px;
+  min-height: 32px;
+  padding: 0 8px;
   cursor: pointer;
   transition: background 0.12s;
-  border-radius: 6px;
-  margin-bottom: 4px;
-
-  &:last-child {
-    margin-bottom: 0;
-  }
+  border-radius: 5px;
 
   &:hover,
   &.selected {
@@ -632,12 +644,19 @@ watch(() => props.visible, (newVal) => {
     color: var(--td-text-color-placeholder);
     cursor: default;
     text-align: center;
-    padding: 20px 8px;
+    padding: 16px 8px;
+    min-height: auto;
 
     &:hover {
       background: transparent;
     }
   }
+
+  :deep(.agent-avatar-small) {
+    width: 22px;
+    height: 22px;
+    border-radius: 5px;
+  }
 }
 
 .agent-option-name {
@@ -648,19 +667,22 @@ watch(() => props.visible, (newVal) => {
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
-  line-height: 1.4;
+  line-height: 22px;
 }
 
 .shared-tag {
   font-size: 10px;
   color: var(--td-text-color-placeholder);
   flex-shrink: 0;
+  line-height: 22px;
 }
 
 .agent-option-actions {
   display: flex;
   align-items: center;
-  gap: 4px;
+  justify-content: center;
+  width: 22px;
+  height: 22px;
   flex-shrink: 0;
 }
 
@@ -668,16 +690,24 @@ watch(() => props.visible, (newVal) => {
   flex-shrink: 0;
   color: var(--td-warning-color, #ed7b2f);
   cursor: default;
+  display: block;
+  line-height: 1;
 }
 
 .builtin-icon {
   display: flex;
   align-items: center;
   justify-content: center;
-  width: 24px;
-  height: 24px;
-  border-radius: 6px;
+  width: 22px;
+  height: 22px;
+  border-radius: 5px;
   flex-shrink: 0;
+  line-height: 1;
+
+  :deep(.t-icon) {
+    display: block;
+    line-height: 1;
+  }
 
   &.normal {
     background: var(--td-brand-color-light);
@@ -699,12 +729,14 @@ watch(() => props.visible, (newVal) => {
   display: flex;
   align-items: center;
   justify-content: center;
-  width: 24px;
-  height: 24px;
-  border-radius: 6px;
+  width: 22px;
+  height: 22px;
+  border-radius: 5px;
   flex-shrink: 0;
-  font-size: 16px;
+  font-size: 14px;
+  line-height: 1;
   background: var(--td-bg-color-secondarycontainer, #f5f5f5);
+  overflow: hidden;
 
   &.detail-icon {
     width: 28px;
@@ -716,6 +748,17 @@ watch(() => props.visible, (newVal) => {
 /* 详情浮层 */
 .agent-detail-panel {
   box-sizing: border-box;
+  position: relative;
+
+  // 左侧透明桥接区：承接从选项移入的鼠标，避免经过间隙时浮层消失
+  &::before {
+    content: '';
+    position: absolute;
+    left: -12px;
+    top: 0;
+    width: 12px;
+    height: 100%;
+  }
 }
 
 .agent-detail-panel-inner {
@@ -830,6 +873,15 @@ watch(() => props.visible, (newVal) => {
   background: var(--td-bg-color-container);
 }
 
+.detail-not-ready-shared-hint {
+  display: block;
+  width: 100%;
+  margin-top: 2px;
+  font-size: 10px;
+  line-height: 1.4;
+  color: var(--td-text-color-placeholder);
+}
+
 .detail-desc {
   margin: 0 0 8px;
   font-size: 12px;
diff --git a/frontend/src/components/Input-field.vue b/frontend/src/components/Input-field.vue
index fb48c969..d55ef050 100644
--- a/frontend/src/components/Input-field.vue
+++ b/frontend/src/components/Input-field.vue
@@ -30,6 +30,7 @@ import {
   getAgentNotReadyReasonKeys,
   resolveAgentNotReadySection,
   resolveAgentNotReadyHighlight,
+  canLocallyConfigureAgent,
   type AgentNotReadyReasonKey,
 } from '@/utils/agent-readiness';
 import { formatLocalizedList } from '@/utils/format-list';
@@ -2047,25 +2048,34 @@ const showAgentNotReadyMessage = (
   sourceTenantId?: string,
 ) => {
   const reasonsText = formatLocalizedList(reasons, locale.value)
-  const section = resolveAgentNotReadySection(reasonKeys || ['summary_model'])
-  const highlight = resolveAgentNotReadyHighlight(reasonKeys || ['summary_model'])
+  const isRemoteShared = !canLocallyConfigureAgent(sourceTenantId)
 
   const messageContent = h('div', { style: 'display: flex; flex-direction: column; gap: 8px; max-width: 320px;' }, [
-    h('span', { style: 'color: var(--td-text-color-primary); line-height: 1.5;' }, t('input.agentNotReadyDetail', { agentName: agent.name, reasons: reasonsText })),
-    h('a', {
-      href: '#',
-      onClick: (e: Event) => {
-        e.preventDefault();
-        goToAgentEditor(agent, section, highlight, sourceTenantId);
-      },
-      style: 'color: var(--td-brand-color); text-decoration: none; font-weight: 500; cursor: pointer; align-self: flex-start;',
-      onMouseenter: (e: Event) => {
-        (e.target as HTMLElement).style.textDecoration = 'underline';
-      },
-      onMouseleave: (e: Event) => {
-        (e.target as HTMLElement).style.textDecoration = 'none';
-      }
-    }, t('input.goToAgentEditor'))
+    h(
+      'span',
+      { style: 'color: var(--td-text-color-primary); line-height: 1.5;' },
+      isRemoteShared
+        ? t('input.sharedAgentNotReadyDetail', { agentName: agent.name, reasons: reasonsText })
+        : t('input.agentNotReadyDetail', { agentName: agent.name, reasons: reasonsText }),
+    ),
+    ...(isRemoteShared ? [] : [
+      h('a', {
+        href: '#',
+        onClick: (e: Event) => {
+          e.preventDefault();
+          const section = resolveAgentNotReadySection(reasonKeys || ['summary_model'])
+          const highlight = resolveAgentNotReadyHighlight(reasonKeys || ['summary_model'])
+          goToAgentEditor(agent, section, highlight, sourceTenantId);
+        },
+        style: 'color: var(--td-brand-color); text-decoration: none; font-weight: 500; cursor: pointer; align-self: flex-start;',
+        onMouseenter: (e: Event) => {
+          (e.target as HTMLElement).style.textDecoration = 'underline';
+        },
+        onMouseleave: (e: Event) => {
+          (e.target as HTMLElement).style.textDecoration = 'none';
+        }
+      }, t('input.goToAgentEditor')),
+    ]),
   ]);
 
   MessagePlugin.warning({
@@ -2233,9 +2243,7 @@ defineExpose({
           <!-- Agent 选择器下拉菜单 -->
           <AgentSelector :visible="showAgentModeSelector" :anchorEl="agentModeButtonRef"
             :currentAgentId="selectedAgentId" :agents="enabledAgents" :all-models="allModels"
-            @close="closeAgentModeSelector"
-            @select="handleSelectAgent"
-            @not-ready="handleAgentNotReady" />
+            @close="closeAgentModeSelector" @select="handleSelectAgent" @not-ready="handleAgentNotReady" />
 
           <!-- WebSearch 开关按钮 -->
           <t-tooltip placement="top" theme="light" :popupProps="{ overlayClassName: 'input-field-tooltip' }">
@@ -2243,7 +2251,7 @@ defineExpose({
               <div v-if="isWebSearchDisabledByAgent" class="tooltip-with-link">
                 <span>{{ $t('input.webSearchDisabledByAgent') }}</span>
                 <a href="#" @click.prevent="handleGoToAgentSettings('websearch')">{{ $t('input.goToAgentSettings')
-                  }}</a>
+                }}</a>
               </div>
               <span v-else-if="isWebSearchConfigured">{{ isWebSearchEnabled ? $t('input.webSearch.toggleOff') :
                 $t('input.webSearch.toggleOn') }}</span>
@@ -2308,7 +2316,7 @@ defineExpose({
                   d="M21.44 11.05l-9.19 9.19a6 6 0 0 1-8.49-8.49l9.19-9.19a4 4 0 0 1 5.66 5.66l-9.2 9.19a2 2 0 0 1-2.83-2.83l8.49-8.48" />
               </svg>
               <span v-if="uploadedAttachments.length > 0" class="attachment-count">{{ uploadedAttachments.length
-                }}</span>
+              }}</span>
             </div>
           </t-tooltip>
 
@@ -2318,7 +2326,7 @@ defineExpose({
               <div v-if="isKnowledgeBaseDisabledByAgent" class="tooltip-with-link">
                 <span>{{ $t('input.kbDisabledByAgent') }}</span>
                 <a href="#" @click.prevent="handleGoToAgentSettings('knowledge')">{{ $t('input.goToAgentSettings')
-                  }}</a>
+                }}</a>
               </div>
               <span v-else>{{ allSelectedItems.length > 0 ? $t('input.knowledgeBaseWithCount', {
                 count:
@@ -2368,13 +2376,8 @@ defineExpose({
                 </button>
               </div>
               <div class="model-selector-content">
-                <div
-                  v-for="model in availableModels"
-                  :key="model.id"
-                  class="model-option"
-                  :class="{ selected: model.id === selectedModelId }"
-                  @click="handleModelChange(model.id || '')"
-                >
+                <div v-for="model in availableModels" :key="model.id" class="model-option"
+                  :class="{ selected: model.id === selectedModelId }" @click="handleModelChange(model.id || '')">
                   <div class="model-option-left">
                     <div class="model-option-icon">
                       <t-icon name="chat" size="14px" />
@@ -3191,8 +3194,15 @@ const getImgSrc = (url: string) => {
 }
 
 @keyframes modelSelectorFadeIn {
-  from { opacity: 0; transform: scale(0.98); }
-  to { opacity: 1; transform: scale(1); }
+  from {
+    opacity: 0;
+    transform: scale(0.98);
+  }
+
+  to {
+    opacity: 1;
+    transform: scale(1);
+  }
 }
 
 .model-selector-header {
diff --git a/frontend/src/components/IntegrationsAgentFilter.vue b/frontend/src/components/IntegrationsAgentFilter.vue
index be12ebad..b662b2d5 100644
--- a/frontend/src/components/IntegrationsAgentFilter.vue
+++ b/frontend/src/components/IntegrationsAgentFilter.vue
@@ -1,18 +1,8 @@
 <template>
-  <t-dropdown
-    :options="options"
-    trigger="click"
-    placement="bottom-left"
-    attach="body"
-    :max-column-width="240"
-    @click="onSelect"
-  >
-    <button
-      type="button"
-      class="integrations-agent-filter"
-      :class="{ 'integrations-agent-filter--active': modelValue }"
-      :aria-label="ariaLabel"
-    >
+  <t-dropdown :options="options" trigger="click" placement="bottom-left" attach="body" :max-column-width="240"
+    :max-height="280" @click="onSelect">
+    <button type="button" class="integrations-agent-filter" :class="{ 'integrations-agent-filter--active': modelValue }"
+      :aria-label="ariaLabel">
       <t-icon name="filter" size="14px" class="integrations-agent-filter__icon" />
       <span v-if="selectedAgentName" class="integrations-agent-filter__name">{{ selectedAgentName }}</span>
       <t-icon name="chevron-down" size="12px" class="integrations-agent-filter__chevron" />
diff --git a/frontend/src/composables/useChatStreamHandler.ts b/frontend/src/composables/useChatStreamHandler.ts
index eb53763e..c3d59a89 100644
--- a/frontend/src/composables/useChatStreamHandler.ts
+++ b/frontend/src/composables/useChatStreamHandler.ts
@@ -500,7 +500,7 @@ export function useChatStreamHandler(options: UseChatStreamHandlerOptions) {
       onAgentChunkBound?.(message, true)
     }
 
-    message.isAgentMode = true
+    ensureAgentMessageShell(message, dataId)
 
     if (
       loading.value &&
diff --git a/frontend/src/i18n/locales/en-US.ts b/frontend/src/i18n/locales/en-US.ts
index 98c1c825..aa541590 100755
--- a/frontend/src/i18n/locales/en-US.ts
+++ b/frontend/src/i18n/locales/en-US.ts
@@ -1124,6 +1124,7 @@ export default {
       notReadyStatus: 'Setup needed',
       notReadyMissing: 'Missing: {items}',
       configureAction: 'Configure',
+      sharedNotReadyContact: 'Ask the sharing organization admin to finish setup',
     },
     // Built-in agent information
     builtinInfo: {
@@ -2131,6 +2132,7 @@ export default {
     customAgentMissingRerankModel: 'Rerank model',
     goToAgentEditor: 'Go to configure →',
     agentNotReadyDetail: 'Agent "{agentName}" is not ready. Please configure: {reasons}',
+    sharedAgentNotReadyDetail: 'Shared agent "{agentName}" is not ready (missing: {reasons}). Ask the sharing organization admin to finish setup.',
     builtinAgentNotReadyDetail: 'Built-in agent "{agentName}" is not ready. Please configure: {reasons}',
     builtinAgentSettingName: 'Intelligent Reasoning',
     builtinNormalSettingName: 'Quick Q&A',
diff --git a/frontend/src/i18n/locales/ko-KR.ts b/frontend/src/i18n/locales/ko-KR.ts
index e9df51cd..8690e40b 100755
--- a/frontend/src/i18n/locales/ko-KR.ts
+++ b/frontend/src/i18n/locales/ko-KR.ts
@@ -2120,6 +2120,7 @@ export default {
       notReadyStatus: "구성 필요",
       notReadyMissing: "누락: {items}",
       configureAction: "구성",
+      sharedNotReadyContact: "공유한 조직 관리자에게 구성을 요청하세요",
     },
     // 내장 에이전트 정보
     builtinInfo: {
@@ -3904,6 +3905,8 @@ export default {
     goToAgentEditor: "구성으로 이동 →",
     agentNotReadyDetail:
       'Agent "{agentName}"가 준비되지 않았습니다. 다음 항목을 설정해야 합니다: {reasons}',
+    sharedAgentNotReadyDetail:
+      '공유 Agent "{agentName}"가 준비되지 않았습니다(누락: {reasons}). 공유한 조직 관리자에게 구성을 요청하세요.',
     builtinAgentNotReadyDetail:
       '내장 에이전트 "{agentName}"가 준비되지 않았습니다. 다음 항목을 설정해야 합니다: {reasons}',
     builtinAgentSettingName: "에이전트 추론",
diff --git a/frontend/src/i18n/locales/ru-RU.ts b/frontend/src/i18n/locales/ru-RU.ts
index 6ae17300..29ebe476 100755
--- a/frontend/src/i18n/locales/ru-RU.ts
+++ b/frontend/src/i18n/locales/ru-RU.ts
@@ -1038,6 +1038,7 @@ export default {
       notReadyStatus: 'Setup needed',
       notReadyMissing: 'Missing: {items}',
       configureAction: 'Configure',
+      sharedNotReadyContact: 'Ask the sharing organization admin to finish setup',
     },
     builtinInfo: {
       quickAnswer: {
@@ -4242,6 +4243,7 @@ export default {
     agentModeDesc: 'Многошаговое мышление, глубокий анализ',
     agentNotReadyTooltip: 'Agent не готов. Пожалуйста, завершите настройку.',
     agentNotReadyDetail: 'Agent не готов. Пожалуйста, настройте следующее: {reasons}',
+    sharedAgentNotReadyDetail: 'Общий agent «{agentName}» не готов (отсутствует: {reasons}). Обратитесь к администратору организации, которая поделилась agent.',
     agentMissingAllowedTools: 'Разрешённые инструменты',
     agentMissingSummaryModel: 'Модель беседы',
     agentMissingRerankModel: 'Модель переранжирования',
diff --git a/frontend/src/i18n/locales/zh-CN.ts b/frontend/src/i18n/locales/zh-CN.ts
index 2c939c41..fd227988 100755
--- a/frontend/src/i18n/locales/zh-CN.ts
+++ b/frontend/src/i18n/locales/zh-CN.ts
@@ -2116,6 +2116,7 @@ export default {
       notReadyStatus: "待配置",
       notReadyMissing: "缺少 {items}",
       configureAction: "去配置",
+      sharedNotReadyContact: "请联系分享方管理员完成配置",
     },
     // 内置智能体信息
     builtinInfo: {
@@ -3912,6 +3913,7 @@ export default {
     customAgentMissingRerankModel: "重排模型",
     goToAgentEditor: "前往配置 →",
     agentNotReadyDetail: "智能体「{agentName}」未就绪，需要配置以下内容：{reasons}",
+    sharedAgentNotReadyDetail: "共享智能体「{agentName}」尚未就绪（缺少：{reasons}），请联系分享方管理员完成配置。",
     builtinAgentNotReadyDetail: "内置智能体「{agentName}」未就绪，需要配置以下内容：{reasons}",
     builtinAgentSettingName: "智能推理",
     builtinNormalSettingName: "快速问答",
diff --git a/frontend/src/stores/auth.ts b/frontend/src/stores/auth.ts
index 4e2d0d09..ec16f46c 100644
--- a/frontend/src/stores/auth.ts
+++ b/frontend/src/stores/auth.ts
@@ -246,6 +246,7 @@ export const useAuthStore = defineStore('auth', () => {
         if (parsed && typeof parsed === 'object') {
           parsed.selectedAgentId = BUILTIN_QUICK_ANSWER_ID
           parsed.selectedAgentSourceTenantId = null
+          parsed.isAgentEnabled = false
           if (parsed.conversationModels && typeof parsed.conversationModels === 'object') {
             parsed.conversationModels.summaryModelId = ''
             parsed.conversationModels.rerankModelId = ''
diff --git a/frontend/src/stores/settings.ts b/frontend/src/stores/settings.ts
index 4a11a80d..21469d78 100644
--- a/frontend/src/stores/settings.ts
+++ b/frontend/src/stores/settings.ts
@@ -3,6 +3,7 @@ import { nextTick } from "vue";
 import { BUILTIN_QUICK_ANSWER_ID, BUILTIN_SMART_REASONING_ID } from "@/api/agent";
 import { getApiBaseUrl } from "@/utils/api-base";
 import { updateMyPreferences, type UserPreferences } from "@/api/auth";
+import { isAgentStreamAgentId, reconcileBuiltinAgentMode } from "@/utils/agent-mode";
 
 // 定义设置接口
 interface Settings {
@@ -102,10 +103,21 @@ const defaultSettings: Settings = {
   autoCheckUpdate: true,
 };
 
+/** Keep builtin agent id and isAgentEnabled in sync after localStorage reload. */
+function loadAndReconcileSettings(): Settings {
+  const loaded = JSON.parse(
+    localStorage.getItem("WeKnora_settings") || JSON.stringify(defaultSettings),
+  ) as Settings;
+  if (reconcileBuiltinAgentMode(loaded)) {
+    localStorage.setItem("WeKnora_settings", JSON.stringify(loaded));
+  }
+  return loaded;
+}
+
 export const useSettingsStore = defineStore("settings", {
   state: () => ({
     // 从本地存储加载设置，如果没有则使用默认设置
-    settings: JSON.parse(localStorage.getItem("WeKnora_settings") || JSON.stringify(defaultSettings)) as Settings,
+    settings: loadAndReconcileSettings(),
     // 进入会话时拍下"全局默认"的快照；离开会话时还原。非持久化字段：
     // 刷新页面相当于重新走"进入会话"流程，自然会重新拍快照。
     _defaultsSnapshot: null as Settings | null,
@@ -116,6 +128,17 @@ export const useSettingsStore = defineStore("settings", {
   getters: {
     // Agent 是否启用
     isAgentEnabled: (state) => state.settings.isAgentEnabled || false,
+
+    // 当前是否为内置快速问答（优先看 selectedAgentId，避免与 isAgentEnabled 漂移）
+    isQuickAnswerMode: (state) =>
+      (state.settings.selectedAgentId || BUILTIN_QUICK_ANSWER_ID) === BUILTIN_QUICK_ANSWER_ID,
+
+    // 是否走 Agent 流式管线（智能推理 / 自定义 Agent）；快速问答走 RAG 管线
+    isAgentStreamMode: (state) =>
+      isAgentStreamAgentId(
+        state.settings.selectedAgentId,
+        state.settings.isAgentEnabled || false,
+      ),
     
     // Agent 是否就绪（配置完整）
     // 需要满足：1) 配置了允许的工具 2) 设置了对话模型 3) 设置了重排模型
diff --git a/frontend/src/utils/agent-mode.test.mjs b/frontend/src/utils/agent-mode.test.mjs
new file mode 100644
index 00000000..e6e217df
--- /dev/null
+++ b/frontend/src/utils/agent-mode.test.mjs
@@ -0,0 +1,59 @@
+import assert from 'node:assert/strict'
+import test from 'node:test'
+
+const BUILTIN_QUICK_ANSWER_ID = 'builtin-quick-answer'
+const BUILTIN_SMART_REASONING_ID = 'builtin-smart-reasoning'
+
+function isQuickAnswerAgentId(agentId) {
+  return (agentId || BUILTIN_QUICK_ANSWER_ID) === BUILTIN_QUICK_ANSWER_ID
+}
+
+function isAgentStreamAgentId(agentId, isAgentEnabled) {
+  const id = agentId || BUILTIN_QUICK_ANSWER_ID
+  if (id === BUILTIN_QUICK_ANSWER_ID) return false
+  if (id === BUILTIN_SMART_REASONING_ID) return true
+  return isAgentEnabled
+}
+
+function reconcileBuiltinAgentMode(settings) {
+  const agentId = settings.selectedAgentId || BUILTIN_QUICK_ANSWER_ID
+  if (agentId === BUILTIN_QUICK_ANSWER_ID && settings.isAgentEnabled) {
+    settings.isAgentEnabled = false
+    return true
+  }
+  if (agentId === BUILTIN_SMART_REASONING_ID && !settings.isAgentEnabled) {
+    settings.isAgentEnabled = true
+    return true
+  }
+  return false
+}
+
+test('isQuickAnswerAgentId treats builtin quick-answer as RAG mode', () => {
+  assert.equal(isQuickAnswerAgentId('builtin-quick-answer'), true)
+  assert.equal(isQuickAnswerAgentId(undefined), true)
+  assert.equal(isQuickAnswerAgentId('builtin-smart-reasoning'), false)
+})
+
+test('isAgentStreamAgentId prefers selectedAgentId for builtins', () => {
+  assert.equal(
+    isAgentStreamAgentId('builtin-quick-answer', true),
+    false,
+    'stale isAgentEnabled must not flip quick-answer into agent stream',
+  )
+  assert.equal(isAgentStreamAgentId('builtin-smart-reasoning', false), true)
+  assert.equal(isAgentStreamAgentId('custom-agent', true), true)
+  assert.equal(isAgentStreamAgentId('custom-agent', false), false)
+})
+
+test('reconcileBuiltinAgentMode repairs drifted localStorage flags', () => {
+  const quick = { selectedAgentId: 'builtin-quick-answer', isAgentEnabled: true }
+  assert.equal(reconcileBuiltinAgentMode(quick), true)
+  assert.equal(quick.isAgentEnabled, false)
+
+  const reasoning = { selectedAgentId: 'builtin-smart-reasoning', isAgentEnabled: false }
+  assert.equal(reconcileBuiltinAgentMode(reasoning), true)
+  assert.equal(reasoning.isAgentEnabled, true)
+
+  const custom = { selectedAgentId: 'custom-agent', isAgentEnabled: true }
+  assert.equal(reconcileBuiltinAgentMode(custom), false)
+})
diff --git a/frontend/src/utils/agent-mode.ts b/frontend/src/utils/agent-mode.ts
new file mode 100644
index 00000000..6276452c
--- /dev/null
+++ b/frontend/src/utils/agent-mode.ts
@@ -0,0 +1,37 @@
+import {
+  BUILTIN_QUICK_ANSWER_ID,
+  BUILTIN_SMART_REASONING_ID,
+} from '@/api/agent'
+
+/** Whether the selected agent id is the builtin quick-answer (RAG) mode. */
+export function isQuickAnswerAgentId(agentId: string | null | undefined): boolean {
+  return (agentId || BUILTIN_QUICK_ANSWER_ID) === BUILTIN_QUICK_ANSWER_ID
+}
+
+/** Whether requests should use the Agent stream pipeline (not quick-answer RAG). */
+export function isAgentStreamAgentId(
+  agentId: string | null | undefined,
+  isAgentEnabled: boolean,
+): boolean {
+  const id = agentId || BUILTIN_QUICK_ANSWER_ID
+  if (id === BUILTIN_QUICK_ANSWER_ID) return false
+  if (id === BUILTIN_SMART_REASONING_ID) return true
+  return isAgentEnabled
+}
+
+/** Reconcile builtin agent id with isAgentEnabled after localStorage reload. */
+export function reconcileBuiltinAgentMode(settings: {
+  selectedAgentId?: string
+  isAgentEnabled: boolean
+}): boolean {
+  const agentId = settings.selectedAgentId || BUILTIN_QUICK_ANSWER_ID
+  if (agentId === BUILTIN_QUICK_ANSWER_ID && settings.isAgentEnabled) {
+    settings.isAgentEnabled = false
+    return true
+  }
+  if (agentId === BUILTIN_SMART_REASONING_ID && !settings.isAgentEnabled) {
+    settings.isAgentEnabled = true
+    return true
+  }
+  return false
+}
diff --git a/frontend/src/utils/agent-readiness.test.mjs b/frontend/src/utils/agent-readiness.test.mjs
index a6f8924c..e5fafb38 100644
--- a/frontend/src/utils/agent-readiness.test.mjs
+++ b/frontend/src/utils/agent-readiness.test.mjs
@@ -3,6 +3,7 @@ import test from 'node:test'
 import {
   agentHasConfiguredChatModel,
   agentRequiresRerankModel,
+  canLocallyConfigureAgent,
   getAgentNotReadyReasonKeys,
   resolveAgentNotReadySection,
   resolveAgentNotReadyHighlight,
@@ -100,3 +101,22 @@ test('getAgentNotReadyReasonKeys does not treat current shared context as shared
     { isAgentMode: false, isSharedAgent: false },
   ), ['summary_model'])
 })
+
+test('getAgentNotReadyReasonKeys treats empty allowed_tools as ready via backend defaults', () => {
+  assert.deepEqual(getAgentNotReadyReasonKeys(
+    {
+      model_id: 'chat-1',
+      rerank_model_id: 'rerank-1',
+      kb_selection_mode: 'all',
+      allowed_tools: [],
+    },
+    [{ id: 'chat-1', type: 'KnowledgeQA' }, { id: 'rerank-1', type: 'Rerank' }],
+    { isAgentMode: true, isSharedAgent: false },
+  ), [])
+})
+
+test('canLocallyConfigureAgent is false for shared agents', () => {
+  assert.equal(canLocallyConfigureAgent('42'), false)
+  assert.equal(canLocallyConfigureAgent(undefined), true)
+  assert.equal(canLocallyConfigureAgent(''), true)
+})
diff --git a/frontend/src/utils/agent-readiness.ts b/frontend/src/utils/agent-readiness.ts
index 7355ce4c..6b6bebcc 100644
--- a/frontend/src/utils/agent-readiness.ts
+++ b/frontend/src/utils/agent-readiness.ts
@@ -67,13 +67,14 @@ export function getAgentNotReadyReasonKeys(
     }
   }
 
-  if (options.isAgentMode && (!config?.allowed_tools || config.allowed_tools.length === 0)) {
-    reasons.push('allowed_tools')
-  }
-
   return reasons
 }
 
+/** Shared agents are owned by another tenant; receivers cannot edit their config. */
+export function canLocallyConfigureAgent(sourceTenantId?: string): boolean {
+  return !sourceTenantId
+}
+
 /** Map missing-config reasons to the agent editor section that fixes them. */
 export function resolveAgentNotReadySection(reasons: AgentNotReadyReasonKey[]): string {
   if (reasons.includes('summary_model') || reasons.includes('rerank_model')) {
diff --git a/frontend/src/views/chat/index.vue b/frontend/src/views/chat/index.vue
index 56b3712f..5c307ffe 100644
--- a/frontend/src/views/chat/index.vue
+++ b/frontend/src/views/chat/index.vue
@@ -144,7 +144,7 @@ const isAgentStreamSession = () => {
     if (props.embeddedMode) {
         return !!(props.agentId && props.agentId !== 'builtin-quick-answer');
     }
-    return useSettingsStoreInstance.isAgentEnabled;
+    return useSettingsStoreInstance.isAgentStreamMode;
 };
 
 const uiStore = useUIStore();
@@ -623,8 +623,10 @@ const sendMsg = async (value, modelId = '', mentionedItems = [], imageFiles = []
     userHasScrolledUp.value = false;
     scrollToBottom(true);
 
-    // Get agent mode status from settings store
-    const agentEnabled = props.embeddedMode ? (props.agentId && props.agentId !== 'builtin-quick-answer') : useSettingsStoreInstance.isAgentEnabled;
+    // Get agent mode status from settings store (prefer selectedAgentId for builtins)
+    const agentEnabled = props.embeddedMode
+        ? (props.agentId && props.agentId !== 'builtin-quick-answer')
+        : useSettingsStoreInstance.isAgentStreamMode;
 
     // Get web search status from settings store
     const webSearchEnabled = props.embeddedMode ? false : useSettingsStoreInstance.isWebSearchEnabled;