fastmcp/tests/tasks/server/test_task_protocol.py
Jeremiah Lowin 5fa2883670
Implement SEP-2663 tasks extension: TasksExtension, poll-based task lifecycle
TasksExtension serves io.modelcontextprotocol/tasks on the extension API:
a decide-and-task tools/call interceptor (era-gated to modern connections),
tasks/get with inlined results and inputRequests, tasks/update delivering
poll-based in-task elicitation, tasks/cancel, durable creation, and
auth-scoped task isolation. Wire models validate against the vendored
ext-tasks schema. Worker-side Context hooks are refcounted so sibling
servers cannot strand each other's workers.

Co-Authored-By: Claude <noreply@anthropic.com>
2026-07-21 23:00:38 -04:00

53 lines
1.7 KiB
Python

"""Protocol-level task behavior for SEP-2663 tasks.
Generic protocol behaviors driven in-process via the task helpers: a submitted
task carries a server-generated id and a TTL, and a task whose tool raises
surfaces its error rather than a result.
"""
from __future__ import annotations
from fastmcp import FastMCP
from fastmcp.exceptions import ToolError
from fastmcp_tasks import TasksExtension
from tests.tasks.task_helpers import (
run_task,
running_task_server,
submit_task,
)
def _task_server() -> FastMCP:
mcp = FastMCP("task-test-server")
mcp.add_extension(TasksExtension())
@mcp.tool(task=True)
async def simple_tool(message: str) -> str:
return f"Processed: {message}"
@mcp.tool(task=True)
async def failing_tool() -> str:
raise ToolError("This tool always fails")
return mcp
async def test_task_metadata_includes_task_id_and_ttl():
"""A submitted task carries a server-generated id and a positive TTL."""
mcp = _task_server()
async with running_task_server(mcp):
created = await submit_task(mcp, "simple_tool", {"message": "test"})
assert isinstance(created.task_id, str)
assert created.task_id
assert created.ttl_ms is not None and created.ttl_ms > 0
async def test_failed_task_stores_error():
"""A task whose tool raises reaches `failed` and stores the error."""
mcp = _task_server()
async with running_task_server(mcp):
final = await run_task(mcp, "failing_tool", {})
assert final.status == "failed"
assert final.error is not None
assert "This tool always fails" in final.error["message"]
assert final.result is None