Your team's newest developer has mass-committed 47 files across 12 libraries, three state managers, and a date parsing package you've never heard of. Oh — and that developer is an AI agent.

Every framework, library, and abstraction your team adopts adds to the "mental stack" — a concept I've stolen from fighting games. Street Fighter II launched with eight characters and a handful of special moves. Street Fighter 6 has drive impacts, perfect parries, burnout states, and a roster of 29. Both are similar, but the cognitive load is wildly different. Software works the same way.

The mental stack isn't just a human problem anymore. Just as a Street Fighter player can only track so many meters at once, your AI agents are 'reasoning' through a finite context window. Every unnecessary abstraction is a layer they can hallucinate through. A lean mental stack—**minimalism as a technical requirement**—means your agents write better code and your developers move faster.

We'll put this to the test with a decision every frontend team faces: server-side or client-side? We'll trace a single feature through each approach — i18n, forms, accessibility, state management — and stack up the true cognitive cost. I'll share case studies of when this went right and when it went catastrophically wrong.

You'll walk away with a framework for evaluating complexity trade-offs — for your team, for the developers who come after you, and for the agents now writing code alongside you. And if nothing else, you might learn a bit about Street Fighter too.