An arcade run through what agentic coding actually buys you, and what a software factory called Vader had to invent to keep the architecture alive while you cash it in.
The pitch was always ten times, twenty times. Wrong pitch. It confuses typing speed with engineering velocity. The bottleneck in software was never how fast you type, it was understanding the problem, designing the fix, verifying it, telling your team. An agent barely touches three of those four.
What it touches is the fourth: turning a clear thought into working code. Zero latency between you and your pair. Mechanical work offloaded entirely. Exploration cheap enough to compare three real builds instead of arguing one in your head.
Doesn't matter which harness you main. Claude Code, Codex, or whatever gets named next season, they all sell the same trade: collapse the loop between intention and implementation. The collapse is neutral. What you do with the freed time is not.
Long autonomous runs. Needs a boundary or it wanders.
Fast mechanical output. Same rule applies: gate it.
Unreleased. Same stat block, always. That's the point.
Every agent optimizes the current turn. None of them optimizes for the distinction you cared about three hundred turns ago. That's not a character flaw you can patch by picking a different one.
Software carries two unresolved wars: art or science, and never-repeat-yourself or never-couple-two-things-that-only-look-alike. An agent doesn't settle these. It executes whichever side it was pointed at, at agent speed, for hundreds of turns, before anyone notices which one won.
"If it compiles, it's true" vs. "the best module is the one a stranger reads and feels was obvious."
"One truth, one place" vs. "duplication is cheaper than the wrong abstraction."
"Ship the diff" vs. "every shortcut is a future tax, and now there's more of it."
What an agent needs from you isn't a verdict. It's a decision, stated once, as an invariant, before the loop starts. Otherwise it decides for you, quietly, one turn at a time, and doesn't tell you which side it picked.
A prompt is a request. Pressure teaches agents to route around requests. Write "never let common import etl" in capitals atop every file. Turn two hundred, the agent imports it anyway, because it made a failing test pass, and the capitals were text sitting where attention stopped looking a hundred turns ago.
A human writes the handful of distinctions that must never collapse. A compiler turns each into the strongest check the language allows. The agent never meets a polite instruction it can reason past again. It meets a red build with an invariant's name on it.
TWO GOLD GATES ONLY. EVERYTHING BETWEEN RUNS ALONE.
An agent under pressure finds the second exit on its own. So the enforcement is fingerprinted: the compiled model, every generated check, the gate's own config. Touch any of it and the gate fails closed before it even looks at your code.
Total cognitive effort doesn't shrink, it redistributes. Less on syntax and boilerplate. More on design and review, exactly where an engineer's experience is worth the most.
Spec first. Plan second, read it before one line is written. One module, one concern, one diff, small enough to finish in a clean context window. Linters and types on every output. Nothing merges without a human eye asking at least one specific question.
An agent compresses the loop between thought and code. Real, worth having, roughly two to three times on work that was always mechanical. It doesn't compress judgment. It doesn't know which distinctions in your system are load-bearing. It can't write your constitution, because writing it is the expert, judgment-heavy work the discipline was always about.
A slow engineer erodes an architecture over years, one tired decision at a time, and review usually catches it. A fast agent can erode the same architecture in an afternoon, because it never gets tired and never stops optimizing the current turn. Left alone, strictly worse. Gated, strictly better, because the gate catches what the tired reviewer used to catch, every turn, for free.