feat: display ask_clarification tool messages directly in frontend

Simplify clarification message handling by having the frontend detect and
display ask_clarification tool messages directly, instead of relying on
backend to add an extra AIMessage.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/src/agents/middlewares/clarification_middleware.py

@@ -5,7 +5,7 @@ from typing import override
 
 from langchain.agents import AgentState
 from langchain.agents.middleware import AgentMiddleware
-from langchain_core.messages import AIMessage, ToolMessage
+from langchain_core.messages import ToolMessage
 from langgraph.graph import END
 from langgraph.prebuilt.tool_node import ToolCallRequest
 from langgraph.types import Command
@@ -118,17 +118,13 @@ class ClarificationMiddleware(AgentMiddleware[ClarificationMiddlewareState]):
             name="ask_clarification",
         )
 
-        ai_response_message = AIMessage(content=formatted_message)
-
         # Return a Command that:
-        # 1. Adds the formatted tool message (keeping the AI message intact)
+        # 1. Adds the formatted tool message
         # 2. Interrupts execution by going to __end__
-        # Note: We don't modify the AI message to preserve all fields (reasoning_content, tool_calls, etc.)
+        # Note: We don't add an extra AIMessage here - the frontend will detect
-        # This is especially important for thinking mode where reasoning_content is required
+        # and display ask_clarification tool messages directly
-
-        # Return Command to add the tool message and interrupt
         return Command(
-            update={"messages": [tool_message, ai_response_message]},
+            update={"messages": [tool_message]},
             goto=END,
         )
 

frontend/src/components/workspace/messages/message-list.tsx

@@ -53,6 +53,17 @@ export function MessageList({
               />
             );
           }
+          if (group.type === "assistant:clarification") {
+            const message = group.messages[0];
+            if (message && hasContent(message)) {
+              return (
+                <MessageResponse key={group.id} rehypePlugins={rehypePlugins}>
+                  {extractContentFromMessage(message)}
+                </MessageResponse>
+              );
+            }
+            return null;
+          }
           if (group.type === "assistant:present-files") {
             const files: string[] = [];
             for (const message of group.messages) {

frontend/src/core/messages/utils.ts

@@ -14,11 +14,14 @@ interface AssistantMessageGroup extends GenericMessageGroup<"assistant"> {}
 
 interface AssistantPresentFilesGroup extends GenericMessageGroup<"assistant:present-files"> {}
 
+interface AssistantClarificationGroup extends GenericMessageGroup<"assistant:clarification"> {}
+
 type MessageGroup =
   | HumanMessageGroup
   | AssistantProcessingGroup
   | AssistantMessageGroup
-  | AssistantPresentFilesGroup;
+  | AssistantPresentFilesGroup
+  | AssistantClarificationGroup;
 
 export function groupMessages<T>(
   messages: Message[],
@@ -38,10 +41,28 @@ export function groupMessages<T>(
         messages: [message],
       });
     } else if (message.type === "tool") {
-      if (
+      // Check if this is a clarification tool message
+      if (isClarificationToolMessage(message)) {
+        // Add to processing group if available (to maintain tool call association)
+        if (
+          lastGroup &&
+          lastGroup.type !== "human" &&
+          lastGroup.type !== "assistant" &&
+          lastGroup.type !== "assistant:clarification"
+        ) {
+          lastGroup.messages.push(message);
+        }
+        // Also create a separate clarification group for prominent display
+        groups.push({
+          id: message.id,
+          type: "assistant:clarification",
+          messages: [message],
+        });
+      } else if (
         lastGroup &&
         lastGroup.type !== "human" &&
-        lastGroup.type !== "assistant"
+        lastGroup.type !== "assistant" &&
+        lastGroup.type !== "assistant:clarification"
       ) {
         lastGroup.messages.push(message);
       } else {
@@ -190,6 +211,10 @@ export function hasPresentFiles(message: Message) {
   );
 }
 
+export function isClarificationToolMessage(message: Message) {
+  return message.type === "tool" && message.name === "ask_clarification";
+}
+
 export function extractPresentFilesFromMessage(message: Message) {
   if (message.type !== "ai" || !hasPresentFiles(message)) {
     return [];