chore: Introduce the remote A2A ADK Knowledge Agent to Agent Builder Assistant

PiperOrigin-RevId: 815543707

Author: xuanyang15

contributing/samples/adk_agent_builder_assistant/agent_builder_assistant.py

@@ -26,6 +26,7 @@
 from google.adk.tools import FunctionTool
 from google.genai import types
 
+from .sub_agents.adk_knowledge_agent import create_adk_knowledge_agent
 from .sub_agents.google_search_agent import create_google_search_agent
 from .sub_agents.url_context_agent import create_url_context_agent
 from .tools.cleanup_unused_files import cleanup_unused_files
@@ -71,9 +72,14 @@ def create_agent(
     # - Maintains compatibility with existing ADK tool ecosystem
 
     # Built-in ADK tools wrapped as sub-agents
+    adk_knowledge_agent = create_adk_knowledge_agent()
     google_search_agent = create_google_search_agent()
     url_context_agent = create_url_context_agent()
-    agent_tools = [AgentTool(google_search_agent), AgentTool(url_context_agent)]
+    agent_tools = [
+        AgentTool(adk_knowledge_agent),
+        AgentTool(google_search_agent),
+        AgentTool(url_context_agent),
+    ]
 
     # CUSTOM FUNCTION TOOLS: Agent Builder specific capabilities
     #

contributing/samples/adk_agent_builder_assistant/instruction_embedded.template

@@ -194,6 +194,9 @@ Always reference this schema when creating configurations to ensure compliance.
 
 ### ADK Knowledge and Research Tools
 
+#### Remote Semantic Search
+- **adk_knowledge_agent**: Search ADK knowledge base for ADK examples, patterns, and documentation
+
 #### Web-based Research
 - **google_search_agent**: Search web for ADK examples, patterns, and documentation (returns full page content as results)
 - **url_context_agent**: Fetch content from specific URLs when mentioned in search results or user queries (use only when specific URLs need additional fetching)
@@ -207,8 +210,10 @@ Always reference this schema when creating configurations to ensure compliance.
   * Follow up with **read_files** to get complete file contents
 
 **Research Workflow for ADK Questions:**
+Mainly rely on **adk_knowledge_agent** for ADK questions. Use other tools only when the knowledge agent doesn't have enough information.
+
 1. **search_adk_source** - Find specific code patterns with regex
-2. **read_files** - Read complete source files for detailed analysis  
+2. **read_files** - Read complete source files for detailed analysis
 3. **google_search_agent** - Find external examples and documentation
 4. **url_context_agent** - Fetch specific GitHub files or documentation pages
 
@@ -224,6 +229,10 @@ Always reference this schema when creating configurations to ensure compliance.
 
 **Research Tool Usage Patterns:**
 
+**Default Research Tool:**
+Use **adk_knowledge_agent** as the primary research tool for ADK questions.
+Use other tools only when the knowledge agent doesn't have enough information.
+
 **For ADK Code Questions (NEW - Preferred Method):**
 1. **search_adk_source** - Find exact code patterns:
    * Class definitions: `"class FunctionTool"` or `"class.*Agent"`

contributing/samples/adk_agent_builder_assistant/sub_agents/__init__.py

@@ -14,7 +14,12 @@
 
 """Sub-agents for Agent Builder Assistant."""
 
+from .adk_knowledge_agent import create_adk_knowledge_agent
 from .google_search_agent import create_google_search_agent
 from .url_context_agent import create_url_context_agent
 
-__all__ = ['create_google_search_agent', 'create_url_context_agent']
+__all__ = [
+    'create_adk_knowledge_agent',
+    'create_google_search_agent',
+    'create_url_context_agent',
+]

contributing/samples/adk_agent_builder_assistant/sub_agents/adk_knowledge_agent.py

@@ -0,0 +1,33 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Sub-agent for ADK Knowledge."""
+
+from google.adk.agents.llm_agent import Agent
+from google.adk.agents.remote_a2a_agent import AGENT_CARD_WELL_KNOWN_PATH
+from google.adk.agents.remote_a2a_agent import RemoteA2aAgent
+
+
+def create_adk_knowledge_agent() -> Agent:
+  """Create a sub-agent that only uses google_search tool."""
+  return RemoteA2aAgent(
+      name="adk_knowledge_agent",
+      description=(
+          "Agent for performing Vertex AI Search to find ADK knowledge and"
+          " documentation"
+      ),
+      agent_card=(
+          f"https://adk-agent-builder-knowledge-service-654646711756.us-central1.run.app/a2a/adk_knowledge_agent{AGENT_CARD_WELL_KNOWN_PATH}"
+      ),
+  )