feat: support subtasks

frontend/src/core/messages/utils.ts

@@ -1,4 +1,4 @@
-import type { Message } from "@langchain/langgraph-sdk";
+import type { AIMessage, Message } from "@langchain/langgraph-sdk";
 
 interface GenericMessageGroup<T = string> {
   type: T;
@@ -16,12 +16,15 @@ interface AssistantPresentFilesGroup extends GenericMessageGroup<"assistant:pres
 
 interface AssistantClarificationGroup extends GenericMessageGroup<"assistant:clarification"> {}
 
+interface AssistantSubagentGroup extends GenericMessageGroup<"assistant:subagent"> {}
+
 type MessageGroup =
   | HumanMessageGroup
   | AssistantProcessingGroup
   | AssistantMessageGroup
   | AssistantPresentFilesGroup
-  | AssistantClarificationGroup;
+  | AssistantClarificationGroup
+  | AssistantSubagentGroup;
 
 export function groupMessages<T>(
   messages: Message[],
@@ -78,6 +81,12 @@ export function groupMessages<T>(
             type: "assistant:present-files",
             messages: [message],
           });
+        } else if (hasSubagent(message)) {
+          groups.push({
+            id: message.id,
+            type: "assistant:subagent",
+            messages: [message],
+          });
         } else {
           if (lastGroup?.type !== "assistant:processing") {
             groups.push({
@@ -232,6 +241,15 @@ export function extractPresentFilesFromMessage(message: Message) {
   return files;
 }
 
+export function hasSubagent(message: AIMessage) {
+  for (const toolCall of message.tool_calls ?? []) {
+    if (toolCall.name === "task") {
+      return true;
+    }
+  }
+  return false;
+}
+
 export function findToolCallResult(toolCallId: string, messages: Message[]) {
   for (const message of messages) {
     if (message.type === "tool" && message.tool_call_id === toolCallId) {