A register of practices —ways of doing things, not products— with their verdict (current, superseded, anti-pattern, unnecessary or it depends), the why, the source with the literal quote and the history: since when it has been so. It exists because what was right months ago may be a mistake today, and neither people nor AI models know it: each carries what it learned.

The verdict says what to do; certainty, how far to trust it. Measured: we measured it and the measurement is in the repository. Documented: the original source says so. Consensus: several independent sources. Opinion: there is not enough evidence, and it says so. A history milestone without a source is drawn with a dashed line: it is not presented as fact.

Every current entry has an expiry date, at most a year away. If it passes without review, it is not deleted: it is marked “not reviewed since”, because an old verdict that looks current is exactly the problem this register wants to avoid. Superseded entries do not expire: what was superseded stays superseded.

The MCP tool practice_check gives an agent the same answers, and with since (its cut-off date) it tells it only what changed afterwards. If there is no entry on a topic, it says so instead of making up a verdict.