When companies compare a custom AI builder with a general digital agency, they're rarely asking about price. They're asking who will own accuracy, latency and governance once the kickoff workshop is over.
Different strengths
Agencies are good at campaigns, content and delivery across many channels. That's real work, and a builder is the wrong hire for it.
A builder is the right hire when the product is a system that underwriters and actuaries have to trust every day: extraction pipelines, pricing APIs, tool layers for agents. Those systems live or die on their numbers.
Ask for the numbers
The simplest test: ask for published metrics and a note on how they were measured. A system nobody can measure is a system nobody owns.