Takeaway: rules that are requested decay, and rules that are enforced don't. Move your standards out of the prompt and into a hook that inspects what the agent actually produced.

My coding agent follows my standards for the first hour. By hour three it is quietly violating the one rule I cared most about, and I find out in review. Every fix I reached for first made it worse: restating the rules, bolding them, moving them into a file the agent reads at session start and drifts from steadily afterwards. The wording was never the problem. The rules were in the wrong layer.

Mine now live in the filesystem. Canonical doctrine sits in one directory, per-repo rules extend it, and a PostToolUse hook inspects the output and vetoes what fails. The agent does not have to remember anything. It has to pass.

This session covers the doctrine layout, the hook itself, real violations it caught that I would otherwise have shipped, and the false positives, because rejecting work that was fine is the honest cost of enforcement. The doctrine directory currently runs to roughly 2,700 lines across two production products. I am dyslexic and cannot review my way out of a bad session, which is why I found this failure at all and why every control I rely on has to be structural.