Root causes of the 2026-09-24 errors turned into mechanisms (BDR-100). hard_deny 'Routing around a guardrail': a refused command is never rerun through a wrapper, alias, heredoc, Makefile target, env file, other shell or other agent; the same clause in 14 agents and in the doctrine's sub-agent rule. make test suite=<file> runs one suite hermetically so the denied env-prefix form is never needed by hand. lib/tests/doctrine-citers.test.sh: every CLAUDE.md "Section" / § Label citation across skills, agents, lib, rules and hooks must resolve to a heading or bold label (flip-tested); its first run fixed rest-api-node.md. Doctrine 'After code changes' step 4: a changed rule, heading, label or threshold → grep every citer in the same commit.
bastien