fix: Rename A2A_AGENT_CARD_URL to AGENT_A2A_RPC_URL

This better reflects the actual content.
It's the URL *for* the agent card, not *of* the agent card.

Author: g3force

README.md

@@ -29,10 +29,10 @@ The SDK supports configuration through environment variables:
 
 ### Application Configuration
 
-| Variable | Description | Default | Example                        |
-|----------|-------------|---------|--------------------------------|
-| `LOGLEVEL` | Sets the log level for the application | `INFO` | `DEBUG`, `INFO`, `WARNING`, `ERROR` |
-| `A2A_AGENT_CARD_URL` | URL for the A2A agent card endpoint | `None` | `https://my-agent.example.com/.well-known/agent-card.json` |
+| Variable            | Description                              | Default | Example                             |
+|---------------------|------------------------------------------|---------|-------------------------------------|
+| `LOGLEVEL`          | Sets the log level for the application   | `INFO`  | `DEBUG`, `INFO`, `WARNING`, `ERROR` |
+| `AGENT_A2A_RPC_URL` | RPC URL inserted into the A2A agent card | `None`  | `https://my-agent.example.com/a2a`  |
 
 ### OpenTelemetry Configuration
 

adk/agenticlayer/agent_to_a2a.py

@@ -71,7 +71,8 @@ def health(_: Request) -> JSONResponse:
 
     # Get the agent card URL from environment variable *only*
     # At this point, we don't know the applications port and the host is unknown when running in k8s or similar
-    agent_card_url = os.environ.get("A2A_AGENT_CARD_URL", None)
+    # A2A_AGENT_CARD_URL is deprecated but still supported for backwards compatibility
+    agent_card_url = os.environ.get("AGENT_A2A_RPC_URL", os.environ.get("A2A_AGENT_CARD_URL", None))
     logger.debug(f"Using agent card url: {agent_card_url}")
 
     # Add startup handler to build the agent card and configure A2A routes