fix: expose enable_tasks() on MCPServer

Github-Issue: #1995

Author: adityuhkapoor

src/mcp/server/mcpserver/server.py

@@ -28,6 +28,7 @@
 from mcp.server.context import LifespanContextT, RequestT, ServerRequestContext
 from mcp.server.elicitation import ElicitationResult, ElicitSchemaModelT, UrlElicitationResult, elicit_with_validation
 from mcp.server.elicitation import elicit_url as _elicit_url
+from mcp.server.experimental.task_support import TaskSupport
 from mcp.server.lowlevel.helper_types import ReadResourceContents
 from mcp.server.lowlevel.server import LifespanResultT, Server
 from mcp.server.lowlevel.server import lifespan as default_lifespan
@@ -42,6 +43,8 @@
 from mcp.server.streamable_http import EventStore
 from mcp.server.streamable_http_manager import StreamableHTTPSessionManager
 from mcp.server.transport_security import TransportSecuritySettings
+from mcp.shared.experimental.tasks.message_queue import TaskMessageQueue
+from mcp.shared.experimental.tasks.store import TaskStore
 from mcp.types import Annotations, ContentBlock, GetPromptResult, Icon, ToolAnnotations
 from mcp.types import Prompt as MCPPrompt
 from mcp.types import PromptArgument as MCPPromptArgument
@@ -488,6 +491,17 @@ async def handle_completion(ref, argument, context):
         """
         return self._lowlevel_server.completion()
 
+    def enable_tasks(
+        self,
+        store: TaskStore | None = None,
+        queue: TaskMessageQueue | None = None,
+    ) -> TaskSupport:
+        """Enable experimental task support.
+
+        WARNING: This API is experimental and may change without notice.
+        """
+        return self._lowlevel_server.experimental.enable_tasks(store=store, queue=queue)
+
     def add_resource(self, resource: Resource) -> None:
         """Add a resource to the server.
 

tests/experimental/tasks/test_spec_compliance.py

@@ -138,6 +138,19 @@ async def handle_get(req: GetTaskRequest) -> GetTaskResult:
     assert caps.tasks.requests.tools is not None
 
 
+def test_mcpserver_enable_tasks_sets_capability() -> None:
+    """MCPServer.enable_tasks() sets tasks.requests.tools.call capability."""
+    from mcp.server.mcpserver.server import MCPServer
+
+    mcp = MCPServer("test")
+    mcp.enable_tasks()
+    caps = _get_capabilities(mcp._lowlevel_server)
+    assert caps.tasks is not None
+    assert caps.tasks.requests is not None
+    assert caps.tasks.requests.tools is not None
+    assert caps.tasks.requests.tools.call is not None
+
+
 class TestClientCapabilities:
     """Clients declare:
     - tasks.list — supports listing operations