refactor: standardize ContextBuilder documentation and remove redundant build_user method from GrpcContextBuilder

Author: guglielmo-san

src/a2a/server/request_handlers/grpc_handler.py

@@ -49,20 +49,15 @@ class GrpcContextBuilder(ABC):
     def build(self, context: grpc.aio.ServicerContext) -> ServerCallContext:
         """Builds a ServerCallContext from a gRPC ServicerContext."""
 
-    @abstractmethod
-    def build_user(self, context: grpc.aio.ServicerContext) -> User:
-        """Builds a User from a gRPC ServicerContext."""
-
 
 class DefaultGrpcContextBuilder(GrpcContextBuilder):
     """Default implementation of GrpcContextBuilder."""
 
     def build(self, context: grpc.aio.ServicerContext) -> ServerCallContext:
         """Builds a ServerCallContext from a gRPC ServicerContext."""
-        user = self.build_user(context)
         state = {'grpc_context': context}
         return ServerCallContext(
-            user=user,
+            user=self.build_user(context),
             state=state,
             requested_extensions=get_requested_extensions(
                 _get_metadata_value(context, HTTP_EXTENSION_HEADER)
@@ -88,6 +83,7 @@ def _get_metadata_value(
         if k.lower() == lower_key
     ]
 
+
 _ERROR_CODE_MAP = {
     types.InvalidRequestError: grpc.StatusCode.INVALID_ARGUMENT,
     types.MethodNotFoundError: grpc.StatusCode.NOT_FOUND,
@@ -125,8 +121,9 @@ def __init__(
             agent_card: The AgentCard describing the agent's capabilities.
             request_handler: The underlying `RequestHandler` instance to
                              delegate requests to.
-            context_builder: Optional custom user builder to extract user from the
-                          gRPC context.
+            context_builder: The GrpcContextBuilder used to construct the
+              ServerCallContext passed to the request_handler. If None the
+              DefaultGrpcContextBuilder is used.
             card_modifier: An optional callback to dynamically modify the public
               agent card before it is served.
         """

src/a2a/server/routes/jsonrpc_dispatcher.py

@@ -161,8 +161,9 @@ def __init__(  # noqa: PLR0913
               requests via http.
             extended_agent_card: An optional, distinct AgentCard to be served
               at the authenticated extended card endpoint.
-            context_builder: Optional custom user builder to extract user from the
-              request.
+            context_builder: The ContextBuilder used to construct the
+              ServerCallContext passed to the request_handler. If None the
+              DefaultContextBuilder is used.
             card_modifier: An optional callback to dynamically modify the public
               agent card before it is served.
             extended_card_modifier: An optional callback to dynamically modify

src/a2a/server/routes/jsonrpc_routes.py

@@ -51,8 +51,9 @@ def create_jsonrpc_routes(  # noqa: PLR0913
         rpc_url: The URL prefix for the RPC endpoints.
         extended_agent_card: An optional, distinct AgentCard to be served
           at the authenticated extended card endpoint.
-        context_builder: Optional custom context builder to extract user from the
-          request.
+        context_builder: The ContextBuilder used to construct the
+          ServerCallContext passed to the request_handler. If None the
+          DefaultContextBuilder is used.
         card_modifier: An optional callback to dynamically modify the public
           agent card before it is served.
         extended_card_modifier: An optional callback to dynamically modify

src/a2a/server/routes/rest_dispatcher.py

@@ -86,8 +86,9 @@ def __init__(  # noqa: PLR0913
             request_handler: The underlying `RequestHandler` instance to delegate requests to.
             extended_agent_card: An optional, distinct AgentCard to be served
               at the authenticated extended card endpoint.
-            context_builder: Optional custom user builder to extract user from the
-              request.
+            context_builder: The ContextBuilder used to construct the
+              ServerCallContext passed to the request_handler. If None the
+              DefaultContextBuilder is used.
             card_modifier: An optional callback to dynamically modify the public
               agent card before it is served.
             extended_card_modifier: An optional callback to dynamically modify

src/a2a/server/routes/rest_routes.py

@@ -64,8 +64,9 @@ def create_rest_routes(  # noqa: PLR0913
           requests via http.
         extended_agent_card: An optional, distinct AgentCard to be served
           at the authenticated extended card endpoint.
-        context_builder: Optional custom user builder to extract user from the
-          request.
+        context_builder: The ContextBuilder used to construct the
+          ServerCallContext passed to the request_handler. If None the
+          DefaultContextBuilder is used.
         card_modifier: An optional callback to dynamically modify the public
           agent card before it is served.
         extended_card_modifier: An optional callback to dynamically modify