fix: Import A2A well known path from A2A sdk

PiperOrigin-RevId: 783036797

contributing/samples/a2a_auth/agent.py

@@ -14,6 +14,7 @@
 
 
 from google.adk.agents import Agent
+from google.adk.agents.remote_a2a_agent import AGENT_CARD_WELL_KNOWN_PATH
 from google.adk.agents.remote_a2a_agent import RemoteA2aAgent
 from google.adk.tools.langchain_tool import LangchainTool
 from langchain_community.tools import YouTubeSearchTool
@@ -41,7 +42,7 @@ bigquery_agent = RemoteA2aAgent(
     name="bigquery_agent",
     description="Help customer to manage notion workspace.",
     agent_card=(
-        "http://localhost:8001/a2a/bigquery_agent/.well-known/agent.json"
+        f"http://localhost:8001/a2a/bigquery_agent{AGENT_CARD_WELL_KNOWN_PATH}"
     ),
 )
 

contributing/samples/a2a_basic/agent.py

@@ -15,6 +15,7 @@
 import random
 
 from google.adk.agents import Agent
+from google.adk.agents.remote_a2a_agent import AGENT_CARD_WELL_KNOWN_PATH
 from google.adk.agents.remote_a2a_agent import RemoteA2aAgent
 from google.adk.tools.example_tool import ExampleTool
 from google.genai import types
@@ -87,7 +88,7 @@ prime_agent = RemoteA2aAgent(
     name="prime_agent",
     description="Agent that handles checking if numbers are prime.",
     agent_card=(
-        "http://localhost:8001/a2a/check_prime_agent/.well-known/agent.json"
+        f"http://localhost:8001/a2a/check_prime_agent{AGENT_CARD_WELL_KNOWN_PATH}"
     ),
 )
 

contributing/samples/a2a_human_in_loop/agent.py

@@ -14,6 +14,7 @@
 
 
 from google.adk import Agent
+from google.adk.agents.remote_a2a_agent import AGENT_CARD_WELL_KNOWN_PATH
 from google.adk.agents.remote_a2a_agent import RemoteA2aAgent
 from google.genai import types
 
@@ -28,7 +29,9 @@ def reimburse(purpose: str, amount: float) -> str:
 approval_agent = RemoteA2aAgent(
     name='approval_agent',
     description='Help approve the reimburse if the amount is greater than 100.',
-    agent_card='http://localhost:8001/a2a/human_in_loop/.well-known/agent.json',
+    agent_card=(
+        f'http://localhost:8001/a2a/human_in_loop{AGENT_CARD_WELL_KNOWN_PATH}'
+    ),
 )
 
 

pyproject.toml

@@ -80,7 +80,7 @@ dev = [
 
 a2a = [
   # go/keep-sorted start
-  "a2a-sdk>=0.2.7;python_version>='3.10'"
+  "a2a-sdk>=0.2.11;python_version>='3.10'"
   # go/keep-sorted end
 ]
 

src/google/adk/agents/remote_a2a_agent.py

@@ -26,7 +26,7 @@ import uuid
 
 try:
   from a2a.client import A2AClient
-  from a2a.client.client import A2ACardResolver  # Import A2ACardResolver
+  from a2a.client.client import A2ACardResolver
   from a2a.types import AgentCard
   from a2a.types import Message as A2AMessage
   from a2a.types import MessageSendParams as A2AMessageSendParams
@@ -35,7 +35,6 @@ try:
   from a2a.types import SendMessageRequest
   from a2a.types import SendMessageSuccessResponse
   from a2a.types import Task as A2ATask
-
 except ImportError as e:
   import sys
 
@@ -46,6 +45,12 @@ except ImportError as e:
   else:
     raise e
 
+try:
+  from a2a.utils.constants import AGENT_CARD_WELL_KNOWN_PATH
+except ImportError:
+  # Fallback for older versions of a2a-sdk.
+  AGENT_CARD_WELL_KNOWN_PATH = "/.well-known/agent.json"
+
 from google.genai import types as genai_types
 import httpx
 
@@ -63,11 +68,18 @@ from ..flows.llm_flows.functions import find_matching_function_call
 from ..utils.feature_decorator import experimental
 from .base_agent import BaseAgent
 
+__all__ = [
+    "A2AClientError",
+    "AGENT_CARD_WELL_KNOWN_PATH",
+    "AgentCardResolutionError",
+    "RemoteA2aAgent",
+]
+
+
 # Constants
 A2A_METADATA_PREFIX = "a2a:"
 DEFAULT_TIMEOUT = 600.0
 
-
 logger = logging.getLogger("google_adk." + __name__)
 
 

src/google/adk/cli/fast_api.py

@@ -1003,6 +1003,7 @@ def get_fast_api_app(
       from a2a.server.request_handlers import DefaultRequestHandler
       from a2a.server.tasks import InMemoryTaskStore
       from a2a.types import AgentCard
+      from a2a.utils.constants import AGENT_CARD_WELL_KNOWN_PATH
 
       from ..a2a.executor.a2a_agent_executor import A2aAgentExecutor
 
@@ -1066,7 +1067,7 @@ def get_fast_api_app(
 
           routes = a2a_app.routes(
               rpc_url=f"/a2a/{app_name}",
-              agent_card_url=f"/a2a/{app_name}/.well-known/agent.json",
+              agent_card_url=f"/a2a/{app_name}{AGENT_CARD_WELL_KNOWN_PATH}",
           )
 
           for new_route in routes: