Coding agents made parallel work cheap. My Mac got the bill. I always have several, and sometimes many tens of, agents working at once. They might be working across many repositories, or in the same codebase through separate Git worktrees. They write code, run the tests, and commit. Pre-commit and pre-push hooks make rigorous validation non-optional: an agent finishes its work, runs the tests, then commits or pushes, and the hook runs much of the same validation again. For a big Swift codebase, a test suite or build can be intensive enough that I have to be careful what else the machine is doing. Multiply that by several agents and worktrees starting together, and a quiet afternoon of delegation turns into fans, swap, and a frozen laptop.