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CKS Documentation

ADR-003

Temporal Validity Constraint: Time-Bounded Fact Semantics

Section titled “Temporal Validity Constraint: Time-Bounded Fact Semantics”

Status: Proposed

Date: 2026-08-04

Category: Architecture Decision Record

Context

Section titled “Context”

cks-core has constraints for ontology (type_hierarchy), reasoning (inference_confidence_conflict, supersession_chain), and provenance (verification_record), but no built-in notion of temporal validity – the fact that a claim may be true only within a certain time window. InferenceStalenessSweeper (cks-runtime, ADR-009) detects stale inference steps, but cks-core itself has no semantic primitive for “this claim is valid until T”.

Decision

Section titled “Decision”

Add TemporalValidityConstraint as a new opt-in constraint in cks.constraints.temporal. It checks every object’s structure for an optional valid_until field (ISO-8601 datetime string). If present and in the past, a WARNING diagnostic is raised: the fact is still structurally valid (no ERROR), but its temporal window has closed.

This is deliberately minimal – no reasoning about time intervals, Allen’s algebra, or temporal logic. It answers exactly one question: “has this fact expired?”, which is the foundation for a future TemporalStalenessSweeper (cks-runtime) that would periodically re-check expired facts, the same way InferenceStalenessSweeper does for inference steps.

Consequences

Section titled “Consequences”
  • Any object can now carry valid_until in its structure; the constraint flags expired ones as WARNING when opted into via extensions.
  • Unblocks a temporal_staleness_sweeper in cks-runtime (future ADR).
  • No breaking change: the field is optional and the constraint is opt-in.