Updates made to allow Orchestrator UI to display which A2A Agent was in charge of putting together the reponse message.

See https://screenshot.googleplex.com/7ZbNPqcLb9GHtuf for demo.

Author: sugoi-yuzuru

a2a_agents/python/adk/samples/orchestrator/agent_executor.py

@@ -14,6 +14,7 @@
 
 import asyncio
 import logging
+import json
 from typing import List, Optional, override
 from google.adk.agents.invocation_context import new_invocation_context_id
 from google.adk.events.event_actions import EventActions
@@ -84,6 +85,20 @@ def convert_event_to_a2a_events_and_save_surface_id_to_subagent_name(
         )
 
         for a2a_event in a2a_events:
+            # Try to populate subagent agent card if available.
+            subagent_card = None
+            if (active_subagent_name := event.author):
+                # We need to find the subagent by name
+                if (subagent := next((sub for sub in invocation_context.agent.sub_agents if sub.name == active_subagent_name), None)):
+                    try:
+                        subagent_card = json.loads(subagent.description)
+                    except Exception:
+                        logger.warning(f"Failed to parse agent description for {active_subagent_name}")
+            if subagent_card:
+                if a2a_event.metadata is None:
+                    a2a_event.metadata = {}
+                a2a_event.metadata["a2a_subagent"] = subagent_card
+                        
             for a2a_part in a2a_event.status.message.parts:
                 if (
                     is_a2ui_part(a2a_part)

samples/client/angular/projects/a2a-chat-canvas/src/lib/components/chat/message/message.html

@@ -23,7 +23,7 @@
 >
   @if (isRoleAgent(role)) {
     <agent-header
-      [agentName]="role.name"
+      [agentName]="getAgentName(role)"
       [agentIconUrl]="role.iconUrl"
       [agentThoughts]="agentThoughts()"
       [showProgressIndicator]="showProgressIndicator()"

samples/client/angular/projects/a2a-chat-canvas/src/lib/components/chat/message/message.ts

@@ -37,6 +37,11 @@ export class Message {
   /** Service for managing chat interactions. */
   private readonly chatService = inject(ChatService);
 
+  protected getAgentName(role: UiAgent) {
+    const rootagentName = role.name;
+    return role.subagentName ? `${rootagentName} + ${role.subagentName}` : rootagentName;
+  }
+
   /** Agent thought contents. */
   protected readonly agentThoughts = computed(() =>
     this.message().contents.filter((content) => containsAgentThought(content)),

samples/client/angular/projects/a2a-chat-canvas/src/lib/services/chat-service.ts

@@ -17,7 +17,7 @@
 import { AgentCard, SendMessageSuccessResponse } from '@a2a-js/sdk';
 import { PART_RESOLVERS } from '@a2a_chat_canvas/a2a-renderer/tokens';
 import { A2A_SERVICE } from '@a2a_chat_canvas/interfaces/a2a-service';
-import { UiMessage, UiMessageContent } from '@a2a_chat_canvas/types/ui-message';
+import { UiAgent, UiMessage, UiMessageContent } from '@a2a_chat_canvas/types/ui-message';
 import { extractA2aPartsFromResponse } from '@a2a_chat_canvas/utils/a2a';
 import { extractA2uiDataParts } from '@a2a_chat_canvas/utils/a2ui';
 import { convertPartToUiMessageContent } from '@a2a_chat_canvas/utils/ui-message-utils';
@@ -148,6 +148,7 @@ export class ChatService {
 
     this.updateLastMessage((msg) => ({
       ...msg,
+      role: this.createRole(response),
       contents: [...msg.contents, ...newContents],
       status: 'completed',
       lastUpdated: new Date().toISOString(),
@@ -246,15 +247,36 @@ export class ChatService {
       type: 'ui_message',
       id: uuid(),
       contextId: this.contextId() ?? '',
-      role: {
-        type: 'ui_agent',
-        name: this.agentCard()?.name ?? 'Agent',
-        iconUrl: this.agentCard()?.iconUrl ?? 'gemini-color.svg',
-      },
+      role: this.createRole(),
       contents: [],
       status: 'pending',
       created: nowTimestamp,
       lastUpdated: nowTimestamp,
     };
   }
+
+  /**
+   * Creates the agent role based on the agent card and the message response if available.
+   *
+   * @param response The reponse message received from the agent.
+   * @returns A new UiAgent object representing the agent that the user is chatting with.
+   */
+  private createRole(response?: SendMessageSuccessResponse): UiAgent {
+    const rootagentRole: UiAgent = {
+      type: 'ui_agent',
+      name: this.agentCard()?.name ?? 'Agent',
+      iconUrl: this.agentCard()?.iconUrl ?? 'gemini-color.svg',
+    };
+
+    const subagentCard = response?.result?.metadata?.['a2a_subagent'];
+    if (!subagentCard) {
+      return rootagentRole;
+    }
+    const agentRole: UiAgent = {
+      ...rootagentRole,
+      subagentName: (subagentCard as AgentCard).name,
+    }
+
+    return agentRole;
+  }
 }

samples/client/angular/projects/a2a-chat-canvas/src/lib/types/ui-message.ts

@@ -35,6 +35,10 @@ export interface UiAgent {
   readonly name: string;
   /** The URL of the agent's icon. */
   readonly iconUrl: string;
+  /** The display name of the sub-agent. */
+  readonly subagentName?: string;
+  /** The URL of the sub-agent's icon. */
+  readonly subagentIconUrl?: string;
 }
 
 /**