You go direct. A recruitment agency is genuinely useful when you are hiring a permanent employee and need a pipeline of screened candidates. For fractional or interim senior technology help, an agency mostly adds a fee, often 18% or more on top of the day rate, for an introduction you can make yourself. The people who do this work are findable directly, and hiring them direct means the whole budget goes to the work, not the finder.
When an agency is worth it, and when it is not
For a permanent senior hire, where you need many candidates screened and a long search run, an agency can earn its fee. For a day or two a week of fractional help, the value it adds is thin: a single introduction, marked up. You can find that person through a referral, their own site or a professional network, and keep the markup for the actual engagement.
What to look for instead of a CV pile
Look for someone who has done the work, not only managed it, on problems like yours. Someone who can talk to your team and your board without changing language. Someone who proposes a small, fixed first engagement rather than selling you a long retainer up front. And someone who hands you something you own at the end, a plan or a working system, not a dependency on them.
How to vet them quickly
Ask for a specific example of a mess they sorted, and exactly what they did. Ask how they would approach your situation in the first two weeks. Be wary of anyone who answers in frameworks and buzzwords rather than specifics. The good ones are concrete, because they have actually done it.
Start with a small, fixed step
A short fixed-scope engagement is the lowest-risk way to test fit before any longer commitment. You learn how they work, they learn your business, and you walk away with something useful whether or not you continue.
That is how a Technology Discovery and Blueprint is built: a short, fixed first engagement, hired direct, with a usable plan at the end.