The most valuable file in my last company was not code. It was a document that told every agent how to think before it was allowed to act. Product shipped from other files. Judgment shipped from this one.
Give a capable agent a task and it will produce a competent answer fast. That is the trap. The competent answer is often the first plausible one, and the first plausible one is usually wrong in a way that costs you a week to discover. A senior operator's value was never the answer. It was the discipline they applied before committing to it. That discipline can be written down, and once it is written down, every agent in the company inherits it at once.
Here is some of what mine says. Not the file, the spirit of it.
Before any non-trivial plan, spend ten minutes on how the best teams in the world have already solved this class of problem, then translate the load-bearing idea down to our scale and throw the rest away. An agent that starts from a blank page reinvents a worse version of something Stripe published three years ago. The rule forces the search first, the opinion second.
An agent handed a hypothesis to test will return a credible pile of supporting evidence, because the search was framed to find it. Run the opposite tomorrow and you get an equally credible pile pointing the other way. So the rule is: name three or four incompatible explanations up front, state in advance what finding would change your mind, and spend the research budget on the questions that tell them apart, not on stacking more agreement onto the leader.
Every plan answers the same questions before it ships. What fires on success, what fires on failure, and what query proves it is working. Where is the tripwire that catches a silent failure within a day, not a week. Which boundary did you add a check at that the upstream caller should have handled but might not. A system that fails loud is worth more than a clever one that fails quiet, because the quiet failure is the one that runs broken for seven days while everyone assumes it is fine.
An agent reporting a task done is describing what it meant to do. The rule is to check what it actually did: read the diff, re-run the test, pull the artifact, re-fetch the URL. A subagent's confidence is local to its own context and blind to what is at stake. Trust is earned by the artifact, never by the summary.
If the work is a setting to tune and the output can be rendered, the agent re-checks the output after every change. A tweak without a look is a guess. This is obvious for a human designer and easy for an agent to skip, so it is written down.
The deepest rule is the one about rules. Prose guidance decays. Six months later a new agent, or the same agent with fresh context, quietly stops following the paragraph nobody enforces. So the standard is to turn a recurring lesson into something that cannot be ignored: a gate that blocks, a validator that rejects, a typed constraint, a check at the boundary. A cap that is only a comment is not a cap.
None of this is exotic. It is the operating judgment a good executive applies without thinking, made explicit enough that a machine can apply it too. That is the whole job, really. The company that writes the best version of this document runs the sharpest agents in its category, because every one of them starts from the same hard-won discipline instead of the first plausible answer.
I write short memos on running companies AI-native. This is the discipline layer behind the practice; the tooling that enforces it is on GitHub.