Some choices should carry into future work: your approved brand voice, an evidence requirement or a project’s privacy boundary. Others concern only the draft in front of you. Saved AI instructions preserve the decisions you want an assistant to reuse, with the reason and the work they apply to. Deciding that a particular email should be shorter need not establish a limit for every email.

Once you reuse a decision in several tools, conflicting copies can make you repeat it. A source of truth is the version you designate as official. It can be a folder of rule files you own and supply to Claude, Codex or another assistant. You approve an update there, then check what each tool receives. One maintained source gives you somewhere to resolve disagreement.

For this example, suppose you have asked for routine client updates under 120 words so clients can read them quickly. Claude has that limit saved; Codex still has an older 150-word version. Which one should change? The answer comes from your approval record. We’ll follow that update into both tools and preserve any exceptions you actually approved.