> We need outcome based billing... I don't want to pay for a service that doesn't deliver.

You can already do this: hire a consultancy to build you a working deliverable for a fixed price. They will be incentivized to prompt their tools well and to avoid tools that are consistently pathological.

They will also charge a lot more than you using the service if they aren’t charlatans

Edit: actually they probably will charge even more if they are charlatans