Check a line from a hook

The harness hook should call the binary, not ask the model. Pipe is not required; argv after -- is the line.

$ ljos-policyd check -- git push origin main
allow
$ ljos-policyd check -- git push --force origin main
deny    git-force-push

A deny is exit 2. The hook turns that into a blocked tool call.

Run only if allowed

$ ljos-policyd exec -- uv run pytest

Same verdict as check. On allow, exec replaces itself with the named program. On deny it prints the verdict and exits 2.

Name a binary that is not on PATH

$ export POLICYD_BIN=$HOME/.local/bin/ljos-policyd
$ ljos policy -- rm -rf /tmp/scratch

ljos looks at POLICYD_BIN first, then PATH. Doctor names the row either way.

Fail closed

$ POLICYD_REQUIRED=1 ljos policy -- ls

Without this, a missing binary is reported and the line is not denied. With it, absence is a deny. Use it on a seat that must not run unchecked argv.

Write pack rules beside the TCB

The binary does not load rules. Pack rules are memory:

$ ljos rule '*--force*' --verdict deny --why "Never force push."
$ ljos policy -- git push --force

ljos policy prints the TCB verdict first, then the pack rule. First deny still wins. Edit a pack rule only when argv law itself changes. Do not write dates, ticket ids, or sitting notes into it.