Rules

Documentation status: reference — see Maturity and evidence.

Rules express constraints, derivations, or decisions interpreted in conceptual context.

Where a rule belongs

A rule belongs in the model when it expresses a durable business truth or constraint. Purely technical policy—HTTP retry, pool size, client cache—stays outside the conceptual model.

Principles

• use domain vocabulary;
• distinguish validation, derivation, and authorization;
• keep derived facts explainable when the reasoning model supports it;
• avoid duplicating the same rule in a view, service, and script.

An action or transition may rely on a rule; the rule should not become an invisible detail of a publication adapter.