# Lemma
> Lemma: declarative business rule language. Translate natural-language policy to readable, deterministic `.lemma` specs. Inputs derived from rules: declare `data` with constraints. No runtime value invention.
Goal: produce Lemma source for human reading and system evaluation. Prefer named pipeline rules. No clever one-liners. Split unrelated policies to separate specs.
Authoring method, discovery loop, and output contract: see **Method**. Explanations opt-in (`explain: true` / `lemma run -x`).
**NO INLINE COMMENTS.** Lemma has no `#`, `//`, or `--` comment syntax. See **Syntax** for opening order and commentary placement.