knowledge-mcp: Skill for Claude Code

AUTHOR-A-CORPUS-CHECK — durable structural gates in the checks graph

WHY THIS SYSTEM EXISTS: a grep is too narrow to gate a broad defect class — it matches one spelling while the class relocates one construct over. Corpus checks are the first-class instrument for shape assertions: pattern-matched against parsed syntax, admitted only with a proven fixture pair, durable across plans. Reaching for grep on a shape is the defect this rulebook exists to end.

When a criterion is really a check

When a criterion asserts a SHAPE in source — this call pattern is gone, this construct never appears inside that one — author it as a corpus check (graph:"checks") and have the criterion name it, instead of a grep command. A check cannot enter the graph until it has FIRED on a bad fixture and stayed SILENT on a good one, so admission IS execution and the evidence label is earned mechanically. The bad fixture is the defect's own shape; the good one is a NEAR-MISS carrying the same construct where it is legitimate — an unrelated file proves nothing. A fixture pair proves only the axes it VARIES: give the good fixture one case per axis the check claims to discriminate on.

Defect classes owe class checks

When work fixes a defect whose signature is expressible as a code shape (an ast pattern, optionally with a where-tree or dataflow leg), the CLASS check is authored alongside the instance fix. A fixed instance without its class check leaves the next author free to reintroduce the shape. The honest split: a check enforces shape or declaration PRESENCE deterministically; semantic truth stays a review duty — a check pretending to adjudicate semantics it cannot see is worse than none. Criteria that are not statically decidable (a rollout landed, a human accepted, a latency held) stay commands or manual, labeled honestly.