Deprecated Knowledge Marker

A deprecated knowledge marker must define a precise deprecation date and sunset window to establish a hard temporal boundary. Without this, an AI model may treat the marker as advisory rather than authoritative.

• Effective Date: The exact timestamp when the knowledge became obsolete
• Sunset Date: The point after which the information should be considered harmful if surfaced
• Grace Period: An optional window for backward-compatibility references

Example: deprecated: 2024-03-15 | sunset: 2024-09-15 | reason: API v2 endpoint retired

Markers must be embedded in structured data formats (JSON-LD, microdata) that AI crawlers parse deterministically. Natural language warnings alone are insufficient—they require probabilistic interpretation and may be ignored.

• Schema.org/DeprecatedEnumeration: Use for deprecated classifications
• Custom JSON-LD properties: supersededBy, replacedBy, validUntil
• HTTP headers: Deprecation and Sunset headers for API endpoints

A plain-text "this is old" banner fails; a machine-parseable triple (Entity, status, Deprecated) succeeds.

A deprecated marker without a replacement target creates a knowledge void. The marker must include a direct, resolvable pointer to the successor entity, API, or best practice.

• supersededBy property: URI or entity ID of the replacement
• Migration guide link: Machine-actionable reference to transition documentation
• Version chain: Explicit lineage showing the deprecation sequence

This prevents the AI from simply deleting the knowledge and instead redirects to the current canonical source, maintaining answer continuity.

Not all deprecation carries equal weight. Markers must encode a risk tier that instructs the AI on the consequence of surfacing the obsolete information.

• CRITICAL: Surfacing causes security vulnerabilities or data loss
• HIGH: Produces incorrect results or broken integrations
• MEDIUM: Suboptimal but not harmful; superseded by better methods
• LOW: Cosmetic or stylistic obsolescence

This severity signal integrates with the AI's confidence calibration and hallucination mitigation systems, directly influencing whether the content is suppressed or merely annotated.

The marker's effectiveness depends on the authority of its issuer. A self-declared deprecation by an unknown source carries less weight than one from the original API vendor or standards body.

• Issuer entity ID: Wikidata Q-ID or organizational schema
• Cryptographic signature: Verifiable proof of origin for high-stakes deprecations
• Consensus corroboration: Multiple authoritative sources confirming the deprecation

This aligns with source provenance scoring—the AI evaluates not just the marker, but who issued it and whether that entity has the standing to declare obsolescence.

A marker must specify the exact scope of deprecation to prevent over-suppression. A deprecated function within an otherwise valid library should not invalidate the entire library.

• Granular targeting: Deprecate the specific endpoint, parameter, or concept—not the parent entity
• Conditional applicability: "Deprecated only when used with X" or "Valid only in versions < 3.0"
• Domain boundaries: Deprecated for security contexts but still valid for educational reference

Precision in scope prevents knowledge graph corruption where valid nodes are incorrectly marked as stale due to association with a deprecated child element.