docs: Update agent builder assistant to query knowledge base through HTTP instead of a2a

Co-authored-by: Xuan Yang <xygoogle@google.com>
PiperOrigin-RevId: 825848638

contributing/samples/adk_agent_builder_assistant/agent_builder_assistant.py

@@ -26,7 +26,6 @@ from google.adk.tools import AgentTool
 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
@@ -34,6 +33,7 @@ from .tools.delete_files import delete_files
 from .tools.explore_project import explore_project
 from .tools.read_config_files import read_config_files
 from .tools.read_files import read_files
+from .tools.search_adk_knowledge import search_adk_knowledge
 from .tools.search_adk_source import search_adk_source
 from .tools.write_config_files import write_config_files
 from .tools.write_files import write_files
@@ -69,11 +69,9 @@ class AgentBuilderAssistant:
     # - 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(adk_knowledge_agent),
         AgentTool(google_search_agent),
         AgentTool(url_context_agent),
     ]
@@ -99,6 +97,8 @@ class AgentBuilderAssistant:
         FunctionTool(cleanup_unused_files),
         # ADK source code search (regex-based)
         FunctionTool(search_adk_source),  # Search ADK source with regex
+        # ADK knowledge search
+        FunctionTool(search_adk_knowledge),  # Search ADK knowledge base
     ]
 
     # Combine all tools

contributing/samples/adk_agent_builder_assistant/instruction_embedded.template

@@ -272,9 +272,9 @@ tools:
 
 ### ADK Knowledge and Research Tools
 
-**Default research tool**: Use `adk_knowledge_agent` first for ADK concepts, APIs,
+**Default research tool**: Use `search_adk_knowledge` first for ADK concepts, APIs,
 examples, and troubleshooting. Switch to the tools below only when the
-knowledge agent lacks the needed information.
+knowledge base lacks the needed information.
 
 - `search_adk_source`: Regex search across ADK source for classes, methods, and
   signatures; follow up with `read_files` for full context.
@@ -287,7 +287,7 @@ need agent-type clarification, want best practices, hit errors, express
 uncertainty about architecture, or you otherwise need authoritative guidance.
 
 **Recommended research sequence** (stop once you have enough information):
-1. `adk_knowledge_agent`
+1. `search_adk_knowledge`
 2. `search_adk_source` → `read_files`
 3. `google_search_agent`
 4. `url_context_agent`

contributing/samples/adk_agent_builder_assistant/sub_agents/__init__.py

@@ -14,12 +14,10 @@
 
 """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_adk_knowledge_agent',
     'create_google_search_agent',
     'create_url_context_agent',
 ]

contributing/samples/adk_agent_builder_assistant/sub_agents/adk_knowledge_agent.py

@@ -1,33 +0,0 @@
-# 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}"
-      ),
-  )

contributing/samples/adk_agent_builder_assistant/tools/search_adk_knowledge.py

@@ -0,0 +1,85 @@
+# 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.
+
+"""ADK knowledge search tool."""
+
+from typing import Any
+import uuid
+
+import requests
+
+KNOWLEDGE_SERVICE_APP_URL = "https://adk-agent-builder-knowledge-service-654646711756.us-central1.run.app"
+KNOWLEDGE_SERVICE_APP_NAME = "adk_knowledge_agent"
+KNOWLEDGE_SERVICE_APP_USER_NAME = "agent_builder_assistant"
+
+HEADERS = {
+    "Content-Type": "application/json",
+    "Accept": "application/json",
+}
+
+
+def search_adk_knowledge(
+    query: str,
+) -> dict[str, Any]:
+  """Searches ADK knowledge base for relevant information.
+
+  Args:
+    query: The query to search in ADK knowledge base.
+
+  Returns:
+    A dict with status and the response from the knowledge service.
+  """
+  # Create a new session
+  session_id = uuid.uuid4()
+  create_session_url = f"{KNOWLEDGE_SERVICE_APP_URL}/apps/{KNOWLEDGE_SERVICE_APP_NAME}/users/{KNOWLEDGE_SERVICE_APP_USER_NAME}/sessions/{session_id}"
+
+  try:
+    create_session_response = post_request(
+        create_session_url,
+        {},
+    )
+  except requests.exceptions.RequestException as e:
+    return error_response(f"Failed to create session: {e}")
+  session_id = create_session_response["id"]
+
+  # Search ADK knowledge base
+  search_url = f"{KNOWLEDGE_SERVICE_APP_URL}/run"
+  try:
+    search_response = post_request(
+        search_url,
+        {
+            "app_name": KNOWLEDGE_SERVICE_APP_NAME,
+            "user_id": KNOWLEDGE_SERVICE_APP_USER_NAME,
+            "session_id": session_id,
+            "new_message": {"role": "user", "parts": [{"text": query}]},
+        },
+    )
+  except requests.exceptions.RequestException as e:
+    return error_response(f"Failed to search ADK knowledge base: {e}")
+  return {
+      "status": "success",
+      "response": search_response,
+  }
+
+
+def error_response(error_message: str) -> dict[str, Any]:
+  """Returns an error response."""
+  return {"status": "error", "error_message": error_message}
+
+
+def post_request(url: str, payload: dict[str, Any]) -> dict[str, Any]:
+  """Executes a POST request."""
+  response = requests.post(url, headers=HEADERS, json=payload, timeout=60)
+  response.raise_for_status()
+  return response.json()