Constant KNOWN_EFFECTS 

pub const KNOWN_EFFECTS: &[(&str, &str)];

Every effect kind the stdlib can declare, each with a one-line note. THE single source: Policy::permissive grants exactly these, and lex docs --effects renders this table for docs/AGENT.md’s quick reference (kept current by lex doc-sync --check in CI). #399’s “keep this set in sync with builtins.rs” used to be a comment-level rule enforced by nobody; adding an effect now means adding one row here, and the doc regenerates from it.