Ask HN: How to choose a tech recruiter, as a candidate?

I'm coming to the end of a non-compete and I'm going to start looking for a new position in the next couple of months. I'm planning on using a recruiter as part of my job search, since the industry I'm looking in is rather fragmented.

I get one or two cold emails from tech recruiters on LinkedIn every week, often from different recruiters at the same couple of agencies.

How do I choose a good recruiter? What do you look for as red flags or positive signals?