Manifesto

Criterion exists because business logic tends to become:

• scattered across services/controllers/UI
• implicit and hard to audit
• hard to reproduce historically
• impossible to explain reliably

The most expensive bugs are often semantic: the system does something "valid" technically, but "wrong" economically or logically.

Criterion draws a hard boundary:

• Data collection happens outside the engine.
• Decisions happen inside the engine.
• Presentation happens after the engine.

A good engine knows nothing about the world. It knows how to think when the world is described to it.

Criterion is intentionally strict:

• contracts are mandatory
• side effects are forbidden
• explainability is required

This is how systems scale without losing trust.