/guard (bro)

All mechanics live in the bro CLI. This skill is policy only — collection, matching, probe evaluation, the fired-set budget, and the judge veto live in @broject/guard and the hooks layer.

Prereq: bro on PATH or npx -y @broject/bro@0.

What it is

Guards are declarative one-line nudges the mega-hook evaluates at session-start, prompt-submit, post-tool, and stop. A guard fires when its when clause — event name, match keys, state probes, optional judge veto — holds, and contributes its say line to the hook's output. They never block and never grant: a guard line is context, not a gate.