My companies aren't startups in the sense intended here, but all my hires over the past few years have been through agencies.
However, we've trained our agencies.
When we have a vacancy we provide "homework." No CV will be considered unless accompanied by answers to the "homework." Any agency that sends us a CV without answers gets a warning. They do it a second time they get blacklisted.
We have two agencies that are now brilliant - we've trained them to pay attention to the job description and only send us CVs that are relevant. All the other agencies have been deep-sixed without prejudice.
However, we've trained our agencies.
When we have a vacancy we provide "homework." No CV will be considered unless accompanied by answers to the "homework." Any agency that sends us a CV without answers gets a warning. They do it a second time they get blacklisted.
We have two agencies that are now brilliant - we've trained them to pay attention to the job description and only send us CVs that are relevant. All the other agencies have been deep-sixed without prejudice.