They often start cold calls with a description of a person's technical abilities, and then ask if I would be interested in interviewing that person.
When that happens, I ask them to define one of the buzzwords that they have just used. "Could you tell me what 'big data' means?" or "What's the difference between AWS and GCE?"
I don't do business with technical recruiters who aren't familiar with the meanings of the terms that they throw around. They have never been more valuable than a regex.