My shell took 2 seconds to start. Then I realized an AI agent was paying that tax hundreds of times a day.
For fifteen years the advice was settled: install oh-my-zsh, add some plugins, get autosuggestions and a pretty git-aware prompt. It made the terminal nicer to sit in front of. That assumption — a human, sitting, typing, one command at a time — is now wrong most of the time.
On my machine, the overwhelming majority of terminal commands are issued by AI agents, not me. And once that flips, every plugin you installed for human comfort turns into a tax the machine pays on your behalf, over and over.
I profiled my own setup and cut shell startup from 2.05 seconds to 0.27 seconds — roughly 7.5x — by deleting tools that added zero value to an agent workflow. Here's what I found, why it matters more now than ever, and how to audit your own machine.
The thing nobody tells you: agents don't reuse your shell
