Before you open the role
First answer yourself: what concrete job should this person close in the first 90 days. No job — don't hire. There is one — write it into the role description instead of vague 'grow content'.
Test task
A test should take a candidate no more than 2 hours and check exactly the skill you need. Don't ask for 'a one-year content strategy' — that's free work and doesn't show what you actually want to see.
First 30 days
Onboarding to product, audience, tone of voice. No volume KPIs. The goal is for the person to start understanding who and why you create content for.
Days 31–60
First independent publications under your supervision. Sync weekly: what works, what doesn't, where the process gets stuck.
Days 61–90
The person leads the direction on their own. Track simple metrics: time per piece, share of rewrites, basic audience response. If all three look healthy — the hire was good.