Before we start

Over the past two years, "I want to use Claude Code / Codex" has gone from install a package, paste a key to something that genuinely requires a technical decision.

The same handful of questions keeps coming up in the community, and the people asking are rarely beginners:

• "I bought API credit. Why does the web app still ask me to log in?"
• "Same account. It ran fine yesterday, today it just spins. What changed?"
• "Why do relay providers make such a fuss about IPs? Can't I just plug in a more expensive proxy myself?"
• "Hosting providers say 'once assigned, the environment does not change.' Isn't that awfully conservative? Wouldn't swapping to a better one be faster?"
• "A long task ran for two minutes and died halfway. Why is retrying it actually worse?"

These look unrelated. They all point at the same thing: most people treat "account" as an indivisible atom, when it is really three kinds of credential + two levels of quota window + a set of identity-consistency constraints stacked on top of each other. Until you separate those layers, none of the questions above has an answer.

This article does not teach you how to game anything, and it contains no adversarial recipes. It does exactly one thing: make the engineering constraints explicit — why things are the way they are, and where each approach hits its ceiling under those constraints.

Roughly 10,000 words, with five explanatory diagrams. By the end you should be able to answer all five questions yourself, and know which path is yours.