Write a Preliminary Rule

from beekeeper import HardPreliminaryRule


class RoleEligibilityRule(HardPreliminaryRule[MyWorker, MyRequest]):
    def check(self, entity: MyWorker, allocation: MyRequest) -> bool:
        return entity.role in allocation.allowed_roles

HardPreliminaryRule[TEntity, TAllocReq] only requires check(entity, allocation) -> bool. A False prunes the candidate from the allocation in stage 2.

Preliminary rules don't see the in-progress schedule. Use them for facts that don't change as more allocations are planned: licensing, role eligibility, qualifications, exemptions, geographic feasibility.

Both entity and allocation are typed as your concrete subclasses — IDE autocomplete and mypy enforcement work without isinstance casts.

For preference scoring instead of binary checks, see Write a Soft Rule.