Sometimes the scope is clear and the plan is sound, and the only thing missing is people to carry it. That is a genuine constraint — but filling it by dropping an unfamiliar body into a technical team rarely works. They need context, backing and someone to escalate to.
Our people work inside your organisation on an agreed scope, and stay part of ours. They have colleagues to consult, a technical lead to escalate to, and someone responsible for whether the work is right. That is the difference between capacity and a headcount number.