refactor: remove extras.py and consolidate error types in utils/errors.py

- Moved all error type definitions (JSONRPCError, A2AError, etc.) to utils/errors.py
- Updated all imports across 15 files to use a2a.utils.errors
- Defined A2ARequest union inline in types/__init__.py
- Deleted the now-redundant extras.py file
- Re-exported error types from types/__init__.py for public API

Author: muscariello

src/a2a/client/errors.py

@@ -2,7 +2,7 @@
 
 from typing import Any
 
-from a2a.types.extras import A2AError
+from a2a.utils.errors import A2AError
 
 
 class A2AClientError(Exception):

src/a2a/server/agent_execution/context.py

@@ -9,11 +9,11 @@
 from a2a.types.a2a_pb2 import (
     Message,
     SendMessageConfiguration,
+    SendMessageRequest,
     Task,
 )
-from a2a.types.extras import InvalidParamsError, SendMessageRequest
 from a2a.utils import get_message_text
-from a2a.utils.errors import ServerError
+from a2a.utils.errors import InvalidParamsError, ServerError
 
 
 class RequestContext:

src/a2a/server/apps/jsonrpc/jsonrpc_app.py

@@ -21,6 +21,7 @@
 from a2a.server.context import ServerCallContext
 from a2a.server.request_handlers.jsonrpc_handler import JSONRPCHandler
 from a2a.server.request_handlers.request_handler import RequestHandler
+from a2a.types import A2ARequest
 from a2a.types.a2a_pb2 import (
     AgentCard,
     CancelTaskRequest,
@@ -33,23 +34,22 @@
     SetTaskPushNotificationConfigRequest,
     SubscribeToTaskRequest,
 )
-from a2a.types.extras import (
+from a2a.utils.constants import (
+    AGENT_CARD_WELL_KNOWN_PATH,
+    DEFAULT_RPC_URL,
+    EXTENDED_AGENT_CARD_PATH,
+    PREV_AGENT_CARD_WELL_KNOWN_PATH,
+)
+from a2a.utils.errors import (
     A2AError,
-    A2ARequest,
     InternalError,
     InvalidParamsError,
     InvalidRequestError,
     JSONParseError,
     MethodNotFoundError,
+    MethodNotImplementedError,
     UnsupportedOperationError,
 )
-from a2a.utils.constants import (
-    AGENT_CARD_WELL_KNOWN_PATH,
-    DEFAULT_RPC_URL,
-    EXTENDED_AGENT_CARD_PATH,
-    PREV_AGENT_CARD_WELL_KNOWN_PATH,
-)
-from a2a.utils.errors import MethodNotImplementedError
 
 
 logger = logging.getLogger(__name__)

src/a2a/server/apps/rest/rest_adapter.py

@@ -37,12 +37,15 @@
 from a2a.server.request_handlers.request_handler import RequestHandler
 from a2a.server.request_handlers.rest_handler import RESTHandler
 from a2a.types.a2a_pb2 import AgentCard
-from a2a.types.extras import AuthenticatedExtendedCardNotConfiguredError
 from a2a.utils.error_handlers import (
     rest_error_handler,
     rest_stream_error_handler,
 )
-from a2a.utils.errors import InvalidRequestError, ServerError
+from a2a.utils.errors import (
+    AuthenticatedExtendedCardNotConfiguredError,
+    InvalidRequestError,
+    ServerError,
+)
 
 
 logger = logging.getLogger(__name__)

src/a2a/server/events/event_consumer.py

@@ -13,8 +13,7 @@
     TaskState,
     TaskStatusUpdateEvent,
 )
-from a2a.types.extras import InternalError
-from a2a.utils.errors import ServerError
+from a2a.utils.errors import InternalError, ServerError
 from a2a.utils.telemetry import SpanKind, trace_class
 
 

src/a2a/server/request_handlers/default_request_handler.py

@@ -42,14 +42,14 @@
     TaskPushNotificationConfig,
     TaskState,
 )
-from a2a.types.extras import (
+from a2a.utils.errors import (
     InternalError,
     InvalidParamsError,
+    ServerError,
     TaskNotCancelableError,
     TaskNotFoundError,
     UnsupportedOperationError,
 )
-from a2a.utils.errors import ServerError
 from a2a.utils.task import apply_history_length
 from a2a.utils.telemetry import SpanKind, trace_class
 

src/a2a/server/request_handlers/grpc_handler.py

@@ -32,9 +32,8 @@
 from a2a.server.request_handlers.request_handler import RequestHandler
 from a2a.types import a2a_pb2
 from a2a.types.a2a_pb2 import AgentCard
-from a2a.types.extras import TaskNotFoundError
 from a2a.utils import proto_utils
-from a2a.utils.errors import ServerError
+from a2a.utils.errors import ServerError, TaskNotFoundError
 from a2a.utils.helpers import validate, validate_async_generator
 
 

src/a2a/server/request_handlers/jsonrpc_handler.py

@@ -24,13 +24,13 @@
     SubscribeToTaskRequest,
     Task,
 )
-from a2a.types.extras import (
+from a2a.utils import proto_utils
+from a2a.utils.errors import (
     AuthenticatedExtendedCardNotConfiguredError,
     InternalError,
+    ServerError,
     TaskNotFoundError,
 )
-from a2a.utils import proto_utils
-from a2a.utils.errors import ServerError
 from a2a.utils.helpers import validate
 from a2a.utils.telemetry import SpanKind, trace_class
 

src/a2a/server/request_handlers/request_handler.py

@@ -17,8 +17,7 @@
     Task,
     TaskPushNotificationConfig,
 )
-from a2a.types.extras import UnsupportedOperationError
-from a2a.utils.errors import ServerError
+from a2a.utils.errors import ServerError, UnsupportedOperationError
 
 
 class RequestHandler(ABC):

src/a2a/server/request_handlers/response_helpers.py

@@ -17,7 +17,7 @@
 from a2a.types.a2a_pb2 import (
     SendMessageResponse as SendMessageResponseProto,
 )
-from a2a.types.extras import (
+from a2a.utils.errors import (
     A2AError,
     InvalidAgentResponseError,
     JSONRPCError,