diff --git a/src/a2a/server/apps/jsonrpc/jsonrpc_app.py b/src/a2a/server/apps/jsonrpc/jsonrpc_app.py
index 5fa1812e..6c565c50 100644
--- a/src/a2a/server/apps/jsonrpc/jsonrpc_app.py
+++ b/src/a2a/server/apps/jsonrpc/jsonrpc_app.py
@@ -45,6 +45,7 @@
 from a2a.utils.constants import (
     AGENT_CARD_WELL_KNOWN_PATH,
     DEFAULT_RPC_URL,
+    EXTENDED_AGENT_CARD_PATH,
 )
 from a2a.utils.errors import MethodNotImplementedError
 
@@ -438,13 +439,16 @@ def build(
         self,
         agent_card_url: str = AGENT_CARD_WELL_KNOWN_PATH,
         rpc_url: str = DEFAULT_RPC_URL,
+        extended_agent_card_url: str = EXTENDED_AGENT_CARD_PATH,
         **kwargs: Any,
     ) -> FastAPI | Starlette:
         """Builds and returns the JSONRPC application instance.
 
         Args:
             agent_card_url: The URL for the agent card endpoint.
-            rpc_url: The URL for the A2A JSON-RPC endpoint
+            rpc_url: The URL for the A2A JSON-RPC endpoint.
+            extended_agent_card_url: The URL for the authenticated extended
+              agent card endpoint.
             **kwargs: Additional keyword arguments to pass to the FastAPI constructor.
 
         Returns: