Experimental Features

Deprecated

The experimental tasks API is deprecated and will be removed in mcp 2.0. Tasks (SEP-1686) were removed from the MCP specification and are expected to return as a separate MCP extension in a future release.

This section documents experimental features in the MCP Python SDK. These features are deprecated and remain available on the 1.x line only for existing users.

Available Experimental Features

Tasks

Tasks enable asynchronous execution of MCP operations. Instead of waiting for a long-running operation to complete, the server returns a task reference immediately. Clients can then poll for status updates and retrieve results when ready.

Tasks are useful for:

Long-running computations that would otherwise block
Batch operations that process many items
Interactive workflows that require user input (elicitation) or LLM assistance (sampling)

Using Experimental APIs

Experimental features are accessed via the .experimental property:

# Server-side
@server.experimental.get_task()
async def handle_get_task(request: GetTaskRequest) -> GetTaskResult:
    ...

# Client-side
result = await session.experimental.call_tool_as_task("tool_name", {"arg": "value"})

Accessing the .experimental properties emits a DeprecationWarning.

Providing Feedback

If you rely on these features and have feedback on their deprecation or the planned MCP extension, please open an issue on the python-sdk repository.