Knack

Your team already decided how not to build this. The decision lives in a PR thread from six months ago, and your coding agent has never read it. So it writes the rejected approach again, and someone has to catch it in review, if they remember. Knack reads the threads instead. It goes through a repo’s merged PRs and pulls out each decision, the approach that was turned down, and the reviewer’s exact words. On 101 merged PRs from Airflow and FastAPI it found 31 rejected approaches, all quoted verbatim. Each one becomes a rule, but a rule can’t block anything until it proves itself on the real code. It has to catch the bad version before the PR, stay quiet after it, survive renames, and miss nothing written by a second model trying to sneak past it, with zero matches on the main branch or the last release. Then a person signs off. From then on Knack sits inside the agent. The moment it tries to bring back a rejected approach, the edit is stopped before the file changes, and the agent sees who decided and why, in their words. That check is plain code. No model, about 17 ms.