diff --git a/frontend-web/src/components/workspace/agents/agent-selector.tsx b/frontend-web/src/components/workspace/agents/agent-selector.tsx
index 3bb0a56b..a3539beb 100644
--- a/frontend-web/src/components/workspace/agents/agent-selector.tsx
+++ b/frontend-web/src/components/workspace/agents/agent-selector.tsx
@@ -20,7 +20,6 @@ import {
 } from "@/components/ui/dialog";
 import { PromptInputButton } from "@/components/ai-elements/prompt-input";
 import { AgentManageDialog } from "@/components/workspace/agents/agent-manage-dialog";
-import { Tooltip } from "@/components/workspace/tooltip";
 import { useAgentSelector, useAgentsPaginated } from "@/core/agents";
 import type { Agent } from "@/core/agents";
 import { getStoredAuth } from "@/core/auth";
@@ -87,7 +86,6 @@ export function AgentSelector({
   };
 
   const triggerLabel = selectedAgent ? desensitize(selectedAgent.name) : "选择 Agent";
-  const iconTooltipLabel = selectedAgent ? triggerLabel : "未选择";
   const iconMode = triggerVariant === "icon";
 
   return (
@@ -95,40 +93,38 @@ export function AgentSelector({
       <Dialog open={open} onOpenChange={setOpen}>
         <DialogTrigger asChild>
           {iconMode ? (
-            <Tooltip content={iconTooltipLabel}>
-              <Button
-                type="button"
-                variant="ghost"
-                size="icon"
-                disabled={disabled}
-                aria-label={selectedAgent ? `已选择智能体：${triggerLabel}` : "选择智能体"}
-                className={cn(
-                  "relative size-9 rounded-full text-muted-foreground shadow-none hover:bg-muted/60 hover:text-foreground",
-                  selectedAgent && "text-amber-600 hover:text-amber-700",
-                  selectedAgent && iconActiveClassName,
-                  iconButtonClassName,
-                )}
-              >
-                <BotIcon className="size-4" />
-                {selectedAgent && (
-                  <span
-                    role="button"
-                    tabIndex={0}
-                    aria-label="清除已选 agent"
-                    className="absolute -right-1 -top-1 inline-flex size-4 items-center justify-center rounded-full border bg-background text-foreground shadow-sm hover:bg-muted"
-                    onClick={handleClear}
-                    onKeyDown={(e) => {
-                      if (e.key === "Enter" || e.key === " ") {
-                        e.preventDefault();
-                        onAgentChange(null);
-                      }
-                    }}
-                  >
-                    <XIcon className="size-2.5" />
-                  </span>
-                )}
-              </Button>
-            </Tooltip>
+            <Button
+              type="button"
+              variant="ghost"
+              size="icon"
+              disabled={disabled}
+              aria-label={selectedAgent ? `已选择智能体：${triggerLabel}` : "选择智能体"}
+              className={cn(
+                "relative size-9 rounded-full text-muted-foreground shadow-none hover:bg-muted/60 hover:text-foreground",
+                selectedAgent && "text-amber-600 hover:text-amber-700",
+                selectedAgent && iconActiveClassName,
+                iconButtonClassName,
+              )}
+            >
+              <BotIcon className="size-4" />
+              {selectedAgent && (
+                <span
+                  role="button"
+                  tabIndex={0}
+                  aria-label="清除已选 agent"
+                  className="absolute -right-1 -top-1 inline-flex size-4 items-center justify-center rounded-full border bg-background text-foreground shadow-sm hover:bg-muted"
+                  onClick={handleClear}
+                  onKeyDown={(e) => {
+                    if (e.key === "Enter" || e.key === " ") {
+                      e.preventDefault();
+                      onAgentChange(null);
+                    }
+                  }}
+                >
+                  <XIcon className="size-2.5" />
+                </span>
+              )}
+            </Button>
           ) : (
             <PromptInputButton
               type="button"
diff --git a/frontend-web/src/core/plugin-management/domain-agent.test.mjs b/frontend-web/src/core/plugin-management/domain-agent.test.mjs
index 06ba2bf9..eb82f447 100644
--- a/frontend-web/src/core/plugin-management/domain-agent.test.mjs
+++ b/frontend-web/src/core/plugin-management/domain-agent.test.mjs
@@ -166,25 +166,3 @@ test("mapped domain overrides the user's manual selection for that incoming mess
     },
   );
 });
-
-test("unmapped incoming url resets auto-selected agent back to default when there is no manual selection", () => {
-  assert.deepEqual(
-    resolveIncomingIframeSelection({
-      pageUrl: "https://another-unknown.example.com/article",
-      mappings: [
-        {
-          id: "m1",
-          domain: "foo.example.com",
-          agentId: "agent-1",
-          enabled: true,
-        },
-      ],
-      availableAgentIds: ["agent-1", "agent-2"],
-      manualSelectedAgentId: null,
-    }),
-    {
-      selectedAgentId: null,
-      forceDefaultAssistant: true,
-    },
-  );
-});
diff --git a/frontend-web/src/pages/IframeChatPage.tsx b/frontend-web/src/pages/IframeChatPage.tsx
index a45384c8..b847d3a0 100644
--- a/frontend-web/src/pages/IframeChatPage.tsx
+++ b/frontend-web/src/pages/IframeChatPage.tsx
@@ -83,13 +83,6 @@ type BrainyChatInterruptMessage = {
   };
   requestId?: string;
 };
-type BrainyUrlContextMessage = {
-  source?: string;
-  type?: string;
-  payload?: {
-    url?: string;
-  };
-};
 type PendingIframeSubmit = {
   message: PromptInputMessage;
   externalContext?: Record<string, unknown>;
@@ -436,33 +429,9 @@ export default function IframeChatPage() {
     [thread],
   );
 
-  const applyIncomingUrlSelection = useCallback(
-    (pageUrl: string | null | undefined) => {
-      const nextSelection = resolveIncomingIframeSelection({
-        pageUrl,
-        mappings: pluginManagementSettings?.domainAgentMappings ?? [],
-        availableAgentIds: selectorLoading
-          ? undefined
-          : selectorAgents.map((agent) => agent.id),
-        manualSelectedAgentId,
-      });
-      setSelectedAgentId(nextSelection.selectedAgentId);
-      setForceDefaultAssistant(nextSelection.forceDefaultAssistant);
-      return nextSelection;
-    },
-    [
-      manualSelectedAgentId,
-      pluginManagementSettings?.domainAgentMappings,
-      selectorAgents,
-      selectorLoading,
-    ],
-  );
-
   useEffect(() => {
     const handleMessage = (
-      event: MessageEvent<
-        BrainyChatSubmitMessage | BrainyChatInterruptMessage | BrainyUrlContextMessage
-      >,
+      event: MessageEvent<BrainyChatSubmitMessage | BrainyChatInterruptMessage>,
     ) => {
       const data = event.data;
       if (data?.source !== "brainy-extension") return;
@@ -470,12 +439,6 @@ export default function IframeChatPage() {
         void handleInterrupt(data as BrainyChatInterruptMessage);
         return;
       }
-      if (data?.type === "brainy:context-url") {
-        applyIncomingUrlSelection(
-          (data as BrainyUrlContextMessage).payload?.url ?? null,
-        );
-        return;
-      }
       if (data?.type !== "brainy:chat-submit") return;
       const submitMessage = data as BrainyChatSubmitMessage;
       const { submitText, files, iframeContext, additionalKwargs } =
@@ -483,6 +446,17 @@ export default function IframeChatPage() {
 
       if (!submitText && files.length === 0) return;
 
+      const nextSelection = resolveIncomingIframeSelection({
+        pageUrl: submitMessage.payload?.pageContext?.url,
+        mappings: pluginManagementSettings?.domainAgentMappings ?? [],
+        availableAgentIds: selectorLoading
+          ? undefined
+          : selectorAgents.map((agent) => agent.id),
+        manualSelectedAgentId,
+      });
+      setSelectedAgentId(nextSelection.selectedAgentId);
+      setForceDefaultAssistant(nextSelection.forceDefaultAssistant);
+
       console.log("收到插件消息", {
         text: submitMessage.payload?.text,
         prompt: submitMessage.payload?.prompt,
@@ -499,8 +473,8 @@ export default function IframeChatPage() {
         message: { text: submitText, files },
         externalContext: iframeContext,
         options: additionalKwargs ? { additionalKwargs } : undefined,
-        targetSelectedAgentId: selectedAgentId,
-        targetForceDefaultAssistant: forceDefaultAssistant,
+        targetSelectedAgentId: nextSelection.selectedAgentId,
+        targetForceDefaultAssistant: nextSelection.forceDefaultAssistant,
       });
     };
 
@@ -509,10 +483,11 @@ export default function IframeChatPage() {
       window.removeEventListener("message", handleMessage);
     };
   }, [
-    applyIncomingUrlSelection,
-    forceDefaultAssistant,
     handleInterrupt,
-    selectedAgentId,
+    manualSelectedAgentId,
+    pluginManagementSettings?.domainAgentMappings,
+    selectorAgents,
+    selectorLoading,
   ]);
 
   const isLandingState = isNewThread && !hasStartedConversation;