Great question — this changed in Prefect 3.x. Recommended approach in Prefect 3.x: - Use

prefect.deployments.run_deployment(...)

from inside a flow. It replaces

create_flow_run_from_deployment(...)

for this use case and will: - Create the child run - Link it as a subflow in the UI by default (

as_subflow=True

) - Optionally wait for completion (

timeout

) Example (wait for completion and propagate failures):

from prefect import flow, get_run_logger
from prefect.deployments import run_deployment

@flow
async def parent_flow():
    logger = get_run_logger()

    child = await run_deployment(
        "transfer/transfer-deployment",   # "flow_name/deployment_name" or deployment ID
        parameters={"param": "abc"},
        timeout=None,                     # wait until the child finishes; use 0 for fire-and-forget
        as_subflow=True,                  # default; shows as a subflow in the UI
    )

    # Optionally propagate child failures to the parent
    if child.state.is_failed():
        exc = await child.state.result(raise_on_failure=False)
        raise exc if isinstance(exc, Exception) else RuntimeError(child.state.message)

    <http://logger.info|logger.info>(f"Created child flow run: {child.id}")

Key notes: - If you trigger via the low-level client (

get_client().create_flow_run_from_deployment(...)

), it will not be linked as a subflow unless you also set a

parent_task_run_id

.

run_deployment()

handles this for you automatically when called inside a flow. - If you want true inline subflow behavior (same process, automatic failure propagation and cancellation), import the flow function and call it directly as

await child_flow(param="abc")

instead of using a deployment. That won’t use a worker or separate infrastructure, though. API reference/source: - run_deployment source