[afourniernv]

What

Let a Python host pass trusted labels into Runner:

runner = Runner.from_toml(source)
outcome = await runner.decide(
    request,
    required_labels=["private", "customer_data"],
    task_id=trusted_task_id,
)

Runner checks the labels before routing. Omitted labels differ from []; neither clears retained task requirements. The result includes approved candidates and their request settings.

Who makes the model calls?

Switchyard's TOML-configured clients make routing-time judge and Decision calls. The Python host makes the final answer calls, resolving returned target names to its deployments and keeping fallbacks within the approved candidates.

This draft does not accept host client callbacks. It is not the client-free factory proposal or a finished gateway integration.

Part of #1164. Based on #931; independent of #1205.

Tests

Fresh wheel: 188 Python tests passed, including four Runner tests. Strict Clippy, Ruff, mypy and formatting passed. No live provider calls during this refresh.