fix: A2A RPC URL got overriden by host and port param of adk api server

PiperOrigin-RevId: 794687030

Author: seanzhougoogle

contributing/samples/a2a_auth/README.md

@@ -157,12 +157,43 @@ You can extend this sample by:
 - Adding audit logging for authentication events
 - Implementing multi-tenant OAuth token management
 
+## Deployment to Other Environments
+
+When deploying the remote BigQuery A2A agent to different environments (e.g., Cloud Run, different hosts/ports), you **must** update the `url` field in the agent card JSON file:
+
+### Local Development
+```json
+{
+  "url": "http://localhost:8001/a2a/bigquery_agent",
+  ...
+}
+```
+
+### Cloud Run Example
+```json
+{
+  "url": "https://your-bigquery-service-abc123-uc.a.run.app/a2a/bigquery_agent",
+  ...
+}
+```
+
+### Custom Host/Port Example
+```json
+{
+  "url": "https://your-domain.com:9000/a2a/bigquery_agent",
+  ...
+}
+```
+
+**Important:** The `url` field in `remote_a2a/bigquery_agent/agent.json` must point to the actual RPC endpoint where your remote BigQuery A2A agent is deployed and accessible.
+
 ## Troubleshooting
 
 **Connection Issues:**
 - Ensure the local ADK web server is running on port 8000
 - Ensure the remote A2A server is running on port 8001
 - Check that no firewall is blocking localhost connections
+- **Verify the `url` field in `remote_a2a/bigquery_agent/agent.json` matches the actual deployed location of your remote A2A server**
 - Verify the agent card URL passed to RemoteA2AAgent constructor matches the running A2A server
 
 
@@ -182,3 +213,4 @@ You can extend this sample by:
 - Check the logs for both the local ADK web server and remote A2A server
 - Verify OAuth tokens are properly passed between agents
 - Ensure agent instructions are clear about authentication requirements
+- **Double-check that the RPC URL in the agent.json file is correct and accessible**

contributing/samples/a2a_auth/remote_a2a/bigquery_agent/agent.json

@@ -24,6 +24,6 @@
       "tags": ["authentication", "oauth", "security"]
     }
   ],
-  "url": "http://localhost:8000/a2a/bigquery_agent",
+  "url": "http://localhost:8001/a2a/bigquery_agent",
   "version": "1.0.0"
 }

contributing/samples/a2a_basic/README.md

@@ -107,15 +107,47 @@ You can extend this sample by:
 - Adding persistent state management
 - Integrating with external APIs or databases
 
+## Deployment to Other Environments
+
+When deploying the remote A2A agent to different environments (e.g., Cloud Run, different hosts/ports), you **must** update the `url` field in the agent card JSON file:
+
+### Local Development
+```json
+{
+  "url": "http://localhost:8001/a2a/check_prime_agent",
+  ...
+}
+```
+
+### Cloud Run Example
+```json
+{
+  "url": "https://your-service-abc123-uc.a.run.app/a2a/check_prime_agent",
+  ...
+}
+```
+
+### Custom Host/Port Example
+```json
+{
+  "url": "https://your-domain.com:9000/a2a/check_prime_agent",
+  ...
+}
+```
+
+**Important:** The `url` field in `remote_a2a/check_prime_agent/agent.json` must point to the actual RPC endpoint where your remote A2A agent is deployed and accessible.
+
 ## Troubleshooting
 
 **Connection Issues:**
 - Ensure the local ADK web server is running on port 8000
 - Ensure the remote A2A server is running on port 8001
 - Check that no firewall is blocking localhost connections
+- **Verify the `url` field in `remote_a2a/check_prime_agent/agent.json` matches the actual deployed location of your remote A2A server**
 - Verify the agent card URL passed to RemoteA2AAgent constructor matches the running A2A server
 
 
 **Agent Not Responding:**
 - Check the logs for both the local ADK web server on port 8000 and remote A2A server on port 8001
 - Verify the agent instructions are clear and unambiguous
+- **Double-check that the RPC URL in the agent.json file is correct and accessible**

contributing/samples/a2a_human_in_loop/README.md

@@ -116,18 +116,50 @@ You can extend this sample by:
 - Integrating with external approval systems or databases
 - Implementing approval timeouts and escalation procedures
 
+## Deployment to Other Environments
+
+When deploying the remote approval A2A agent to different environments (e.g., Cloud Run, different hosts/ports), you **must** update the `url` field in the agent card JSON file:
+
+### Local Development
+```json
+{
+  "url": "http://localhost:8001/a2a/human_in_loop",
+  ...
+}
+```
+
+### Cloud Run Example
+```json
+{
+  "url": "https://your-approval-service-abc123-uc.a.run.app/a2a/human_in_loop",
+  ...
+}
+```
+
+### Custom Host/Port Example
+```json
+{
+  "url": "https://your-domain.com:9000/a2a/human_in_loop",
+  ...
+}
+```
+
+**Important:** The `url` field in `remote_a2a/human_in_loop/agent.json` must point to the actual RPC endpoint where your remote approval A2A agent is deployed and accessible.
+
 ## Troubleshooting
 
 **Connection Issues:**
 - Ensure the local ADK web server is running on port 8000
 - Ensure the remote A2A server is running on port 8001
 - Check that no firewall is blocking localhost connections
+- **Verify the `url` field in `remote_a2a/human_in_loop/agent.json` matches the actual deployed location of your remote A2A server**
 - Verify the agent card URL passed to RemoteA2AAgent constructor matches the running A2A server
 
 **Agent Not Responding:**
 - Check the logs for both the local ADK web server on port 8000 and remote A2A server on port 8001
 - Verify the agent instructions are clear and unambiguous
 - Ensure long-running tool responses are properly formatted with matching IDs
+- **Double-check that the RPC URL in the agent.json file is correct and accessible**
 
 **Approval Workflow Issues:**
 - Verify that updated tool responses use the same `id` and `name` as the original function call

contributing/samples/a2a_human_in_loop/remote_a2a/human_in_loop/agent.json

@@ -24,6 +24,6 @@
       "tags": ["expenses", "processing", "employee-services"]
     }
   ],
-  "url": "http://localhost:8000/a2a/human_in_loop",
+  "url": "http://localhost:8001/a2a/human_in_loop",
   "version": "1.0.0"
 }

src/google/adk/cli/fast_api.py

@@ -352,8 +352,6 @@ async def _get_a2a_runner_async() -> Runner:
         logger.info("Setting up A2A agent: %s", app_name)
 
         try:
-          a2a_rpc_path = f"http://{host}:{port}/a2a/{app_name}"
-
           agent_executor = A2aAgentExecutor(
               runner=create_a2a_runner_loader(app_name),
           )
@@ -365,7 +363,6 @@ async def _get_a2a_runner_async() -> Runner:
           with (p / "agent.json").open("r", encoding="utf-8") as f:
             data = json.load(f)
             agent_card = AgentCard(**data)
-            agent_card.url = a2a_rpc_path
 
           a2a_app = A2AStarletteApplication(
               agent_card=agent_card,