Add empty list_tasks methods

Author: lkawka

src/a2a/client/base_client.py

@@ -14,6 +14,8 @@
 from a2a.types import (
     AgentCard,
     GetTaskPushNotificationConfigParams,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     MessageSendConfiguration,
     MessageSendParams,
@@ -133,6 +135,15 @@ async def get_task(
         """
         return await self._transport.get_task(request, context=context)
 
+    async def list_tasks(
+        self,
+        request: ListTasksParams,
+        *,
+        context: ClientCallContext | None = None,
+    ) -> ListTasksResult:
+        """Retrieves tasks for an agent."""
+        return await self._transport.list_tasks(request, context=context)
+
     async def cancel_task(
         self,
         request: TaskIdParams,

src/a2a/client/client.py

@@ -12,6 +12,8 @@
 from a2a.types import (
     AgentCard,
     GetTaskPushNotificationConfigParams,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     PushNotificationConfig,
     Task,
@@ -131,6 +133,15 @@ async def get_task(
     ) -> Task:
         """Retrieves the current state and history of a specific task."""
 
+    @abstractmethod
+    async def list_tasks(
+        self,
+        request: ListTasksParams,
+        *,
+        context: ClientCallContext | None = None,
+    ) -> ListTasksResult:
+        """Retrieves tasks for an agent."""
+
     @abstractmethod
     async def cancel_task(
         self,

src/a2a/client/transports/base.py

@@ -5,6 +5,8 @@
 from a2a.types import (
     AgentCard,
     GetTaskPushNotificationConfigParams,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     MessageSendParams,
     Task,
@@ -50,6 +52,15 @@ async def get_task(
     ) -> Task:
         """Retrieves the current state and history of a specific task."""
 
+    @abstractmethod
+    async def list_tasks(
+        self,
+        request: ListTasksParams,
+        *,
+        context: ClientCallContext | None = None,
+    ) -> ListTasksResult:
+        """Retrieves tasks for an agent."""
+
     @abstractmethod
     async def cancel_task(
         self,

src/a2a/client/transports/grpc.py

@@ -20,6 +20,8 @@
 from a2a.types import (
     AgentCard,
     GetTaskPushNotificationConfigParams,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     MessageSendParams,
     Task,
@@ -145,6 +147,16 @@ async def get_task(
         )
         return proto_utils.FromProto.task(task)
 
+    async def list_tasks(
+        self,
+        request: ListTasksParams,
+        *,
+        context: ClientCallContext | None = None,
+    ) -> ListTasksResult:
+        """Retrieves tasks for an agent."""
+        # TODO: #515 - Implement method
+        raise NotImplementedError('tasks/list not implemented')
+
     async def cancel_task(
         self,
         request: TaskIdParams,

src/a2a/client/transports/jsonrpc.py

@@ -30,6 +30,8 @@
     GetTaskRequest,
     GetTaskResponse,
     JSONRPCErrorResponse,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     MessageSendParams,
     SendMessageRequest,
@@ -222,6 +224,16 @@ async def get_task(
             raise A2AClientJSONRPCError(response.root)
         return response.root.result
 
+    async def list_tasks(
+        self,
+        request: ListTasksParams,
+        *,
+        context: ClientCallContext | None = None,
+    ) -> ListTasksResult:
+        """Retrieves tasks for an agent."""
+        # TODO: #515 - Implement method
+        raise NotImplementedError('tasks/list not implemented')
+
     async def cancel_task(
         self,
         request: TaskIdParams,

src/a2a/client/transports/rest.py

@@ -17,6 +17,8 @@
 from a2a.types import (
     AgentCard,
     GetTaskPushNotificationConfigParams,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     MessageSendParams,
     Task,
@@ -222,6 +224,16 @@ async def get_task(
         ParseDict(response_data, task)
         return proto_utils.FromProto.task(task)
 
+    async def list_tasks(
+        self,
+        request: ListTasksParams,
+        *,
+        context: ClientCallContext | None = None,
+    ) -> ListTasksResult:
+        """Retrieves tasks for an agent."""
+        # TODO: #515 - Implement method
+        raise NotImplementedError('tasks/list not implemented')
+
     async def cancel_task(
         self,
         request: TaskIdParams,

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

@@ -36,6 +36,7 @@
     JSONRPCRequest,
     JSONRPCResponse,
     ListTaskPushNotificationConfigRequest,
+    ListTasksRequest,
     MethodNotFoundError,
     SendMessageRequest,
     SendStreamingMessageRequest,
@@ -160,6 +161,7 @@ class JSONRPCApplication(ABC):
         SendMessageRequest
         | SendStreamingMessageRequest
         | GetTaskRequest
+        | ListTasksRequest
         | CancelTaskRequest
         | SetTaskPushNotificationConfigRequest
         | GetTaskPushNotificationConfigRequest
@@ -442,6 +444,10 @@ async def _process_non_streaming_request(
                 handler_result = await self.handler.on_get_task(
                     request_obj, context
                 )
+            case ListTasksRequest():
+                handler_result = await self.handler.list_tasks(
+                    request_obj, context
+                )
             case SetTaskPushNotificationConfigRequest():
                 handler_result = (
                     await self.handler.set_push_notification_config(

src/a2a/server/request_handlers/default_request_handler.py

@@ -32,6 +32,8 @@
     InternalError,
     InvalidParamsError,
     ListTaskPushNotificationConfigParams,
+    ListTasksParams,
+    ListTasksResult,
     Message,
     MessageSendParams,
     Task,
@@ -121,6 +123,15 @@ async def on_get_task(
         # Apply historyLength parameter if specified
         return apply_history_length(task, params.history_length)
 
+    async def on_list_tasks(
+        self,
+        params: ListTasksParams,
+        context: ServerCallContext | None = None,
+    ) -> ListTasksResult:
+        """Default handler for 'tasks/list'."""
+        # TODO: #515 - Implement method
+        raise NotImplementedError('tasks/list not implemented')
+
     async def on_cancel_task(
         self, params: TaskIdParams, context: ServerCallContext | None = None
     ) -> Task | None:

src/a2a/server/request_handlers/grpc_handler.py

@@ -331,6 +331,23 @@ async def GetTask(
             await self.abort_context(e, context)
         return a2a_pb2.Task()
 
+    async def ListTasks(
+        self,
+        request: a2a_pb2.ListTasksRequest,
+        context: grpc.aio.ServicerContext,
+    ) -> a2a_pb2.ListTasksResponse:
+        """Handles the 'ListTasks' gRPC method.
+
+        Args:
+            request: The incoming `ListTasksRequest` object.
+            context: Context provided by the server.
+
+        Returns:
+            A `ListTasksResponse` object.
+        """
+        # TODO: #515 - Implement method
+        raise NotImplementedError('tasks/list not implemented')
+
     async def GetAgentCard(
         self,
         request: a2a_pb2.GetAgentCardRequest,

src/a2a/server/request_handlers/jsonrpc_handler.py

@@ -28,6 +28,8 @@
     ListTaskPushNotificationConfigRequest,
     ListTaskPushNotificationConfigResponse,
     ListTaskPushNotificationConfigSuccessResponse,
+    ListTasksRequest,
+    ListTasksResponse,
     Message,
     SendMessageRequest,
     SendMessageResponse,
@@ -359,6 +361,23 @@ async def on_get_task(
             root=JSONRPCErrorResponse(id=request.id, error=TaskNotFoundError())
         )
 
+    async def list_tasks(
+        self,
+        request: ListTasksRequest,
+        context: ServerCallContext | None = None,
+    ) -> ListTasksResponse:
+        """Handles the 'tasks/list' JSON-RPC method.
+
+        Args:
+            request: The incoming `ListTasksRequest` object.
+            context: Context provided by the server.
+
+        Returns:
+            A `ListTasksResponse` object containing the Task or a JSON-RPC error.
+        """
+        # TODO: #515 - Implement method
+        raise NotImplementedError('tasks/list not implemented')
+
     async def list_push_notification_config(
         self,
         request: ListTaskPushNotificationConfigRequest,