For Japanese version, see IRuleEngine-jp.md.

IRuleEngine (Rule Engine Specification)

1. Responsibility Boundary

IRuleEngine evaluates whether inputs, outputs, and execution process signals comply with organizational guardrails and invariant policies.

• Role:

Return rule-evaluation outcomes including compliance, severity, and violation rationale.

• Non-role:

Rule definition storage/lifecycle management is out of scope; this contract focuses on evaluation execution.

2. Contract Signature

namespace AIKernel.Abstractions.Rules;\n\npublic interface IRuleEngine\n{\n    ValueTask<RuleEvaluationResult> EvaluateAsync(\n        string ruleId,\n        RuleEvaluationContext context,\n        CancellationToken cancellationToken = default);\n}

3. Related Use Cases

• UC-13 Runtime signature verification and governance:

Validates policy compliance in addition to signature integrity.

• UC-04 Generation and output polishing:

Checks generated content against formatting/safety rules.

• UC-21 Policy execution:

Acts as core evaluator for guardrail enforcement.

4. Governance & Determinism

• Deterministic evaluation:

Identical ruleId and RuleEvaluationContext should yield identical results.

• Invariant enforcement:

Critical violations must enable fail-closed interruption by upstream orchestration.

• Side-effect free:

EvaluateAsync must not mutate input context or external system state.

5. Exception Contract

This interface does not hard-code exception types. Implementations should explicitly surface:

• Rule resolution failures:

ruleId not found/unavailable.

• Evaluation runtime failures:

Timeouts or engine-level execution errors.

6. Implementation Notes

• Engine diversity:

Implementations may use deterministic rule logic, regex policies, or specialized evaluators.

• Score integration:

Violations can be propagated into broader health signals such as SNR/HealthScore.

Changelog

• v0.0.0 / v0.0.0.0: Initial draft
• v0.0.1 (2026-05-06): Version upgrade aligned with documentation guidelines