AI code review, not model cost, is the real bottleneck

What happened

A new analysis argues that total cost of an AI-assisted engineering decision includes not just model calls, but also review time, rework, and risk of errors escaping to production. Using a baseline example where a model call costs $5 and a 60-minute review costs $80, the model bill represents only 5.9% of the total $85 cost.

Why it matters

Productivity gains from AI remain mixed—a 2025 METR randomized trial found AI tasks took 19% longer on average, while a 2025 DORA survey showed 90% of technology professionals use AI but 30% have little or no trust in AI-generated code. The article suggests that when review is the binding constraint, cutting model costs alone cannot solve the bottleneck; reducing review time from 60 to 40 minutes saves 31.4% of total cost, versus 2.9% from halving model calls.

What to watch

The article identifies a core tension—in autonomous agentic loops with little human oversight, model cost can be the main lever, but in workflows constrained by costly human review, routing and cheaper models become secondary to verification rigor and developer trust in the checking process.