fastmcp.server.tasks.config

TaskConfig for MCP SEP-1686 background task execution modes.

This module defines the configuration for how tools, resources, and prompts handle task-augmented execution as specified in SEP-1686.

Classes

TaskMeta ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/tasks/config.py#L28" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Metadata for task-augmented execution requests.

When passed to call_tool/read_resource/get_prompt, signals that the operation should be submitted as a background task.

Attributes:

• ttl: Client-requested TTL in milliseconds. If None, uses server default.
• fn_key: Docket routing key. Auto-derived from component name if None.

TaskConfig ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/tasks/config.py#L44" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

Configuration for MCP background task execution (SEP-1686).

Controls how a component handles task-augmented requests:

• "forbidden": Component does not support task execution. Clients must not request task augmentation; server returns -32601 if they do.
• "optional": Component supports both synchronous and task execution. Client may request task augmentation or call normally.
• "required": Component requires task execution. Clients must request task augmentation; server returns -32601 if they don't.

Methods:

from_bool ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/tasks/config.py#L82" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

from_bool(cls, value: bool) -> TaskConfig

Convert boolean task flag to TaskConfig.

Args:

• value: True for "optional" mode, False for "forbidden" mode.

Returns:

• TaskConfig with appropriate mode.

supports_tasks ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/tasks/config.py#L93" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

supports_tasks(self) -> bool

Check if this component supports task execution.

Returns:

• True if mode is "optional" or "required", False if "forbidden".

validate_function ^{<a href="https://github.com/PrefectHQ/fastmcp/blob/main/src/fastmcp/server/tasks/config.py#L101" target="_blank"><Icon icon="github" style="width: 14px; height: 14px;" /></a>}

validate_function(self, fn: Callable[..., Any], name: str) -> None

Validate that function is compatible with this task config.

Task execution requires:

1. fastmcp[tasks] to be installed (pydocket)
2. Async functions

Raises ImportError if mode is "optional" or "required" but pydocket is not installed. Raises ValueError if function is synchronous.

Args:

• fn: The function to validate (handles callable classes and staticmethods).
• name: Name for error messages.

Raises:

• ImportError: If task execution is enabled but pydocket not installed.
• ValueError: If task execution is enabled but function is sync.