The speed is really cool but the fact that your rules are written as rust code meaning that new rules need a new binary. That might be fine but just wanted to point it out to anyone who's interested.
quick correction: built-in rules are compiled in, but foxguard also loads Semgrep-compatible YAML rules at runtime via --rules <path> (or .foxguard.yml). You can add or modify rules without touching the binary. The rust-coded rules are just the default pack for zero-config speed :D