System Intent

Effectus exists to make rule execution deterministic, explainable, and safe under change. The engine turns facts (typed, versioned data from multiple sources) into effects (verbs that do real work) using rules and flows that are validated before they ever run.

Core Intent

• Deterministic outcomes: the same facts and rules produce the same effects. Time, randomness, and IO are explicit and traceable.
• Typed contracts everywhere: fact schemas and verb interfaces are the source of truth. Runtime enforcement is optional but available for strict environments.
• Compile before run: rules and flows are parsed, type-checked, and linted before deployment. Fail fast, not in production.
• Explicit capabilities: every verb declares required capabilities and resources to enable safe planning, concurrency rules, and security checks.
• Hot reload without chaos: new rulesets are compiled and validated before swapping into production, with safe rollback on failure.
• Composable bundles: rules, schemas, and verbs are packaged, versioned, and resolved with checksums and compatibility constraints.

What “Correct” Means

• A rule cannot reference unknown facts or call verbs with incompatible types.
• A mutating verb must declare its inverse and concurrency semantics.
• Expressions cannot rely on unsafe or nondeterministic operations without an explicit policy.
• Facts can come from multiple sources, but their merge rules must be explicit and repeatable.

If a change makes any of the above ambiguous, it is a bug by definition.