seo-entity-linking (M6)

Entity linkage tells search engines and AI systems which real-world thing a page is about and ties it to the Knowledge Graph. Reference: references/schema-tier1.md (the sameAs/@id/Person+Organization rules). This module owns the sameAs detail M5 defers here.

Audits

Working from the PageSnapshot (rendered_dom if present, else raw_html):

1. sameAs identity links: for Organization/Person entities, check for sameAs[] resolving to canonical identities — Wikidata QID, Wikipedia, LinkedIn, Crunchbase, official social/company profiles. Wikidata is the strongest Knowledge Graph target.
2. Primary entity defined: confirm exactly one clear primary entity per page (via @id + mainEntity/mainEntityOfPage), not an ambiguous or missing subject.
3. Entity consistency (local): for LocalBusiness, verify NAP (name, address, telephone) in schema matches visible on-page NAP and is internally consistent across blocks.
4. Entity density: count distinct linked/marked entities (@idd nodes, sameAs targets, about/mentions) — flag thin pages with no resolvable entity references.

Fixes

• AUTO (fixable: auto): inject a sameAs[] array on Organization/Person using only user-confirmed URLs, and add about/mentions entity references to existing schema. Additive, deterministic diffs for fix. Never invent identity links — if a URL is unconfirmed, leave a clearly-marked TODO placeholder the user fills.
• PROPOSED (fixable: proposed): a candidate Wikidata/LinkedIn match found by lookup — drafted for per-item human accept, never auto-written.
• ADVISORY (fixable: advisory): "establish a Wikidata entity / claim profiles" when none exist — guidance only, the tool writes nothing.

Verification

• dom_assert: confirm sameAs/@id/mainEntity present and well-formed in the parsed JSON-LD.
• Resolve each sameAs URL (Tier 1 Wikidata lookup) to confirm it is live and refers to the asserted entity — a dead or mismatched link is a fail, not a pass.
• When the live lookup tier is unavailable, status is needs_api, never a false pass.

Findings

Emit findings per schema/finding.schema.json. Examples:

• M6.organization.missing_sameas — Organization has no sameAs[] (status fail, severity 4, fixable: proposed, axis ai, confidence directional).
• M6.person.no_wikidata_link — author Person lacks a Wikidata/LinkedIn identity link (status warn, severity 2, fixable: proposed, axis ai, confidence directional).
• M6.page.no_primary_entity — no single defined primary entity (@id/mainEntity) on the page (status warn, severity 4, fixable: advisory, axis ai, confidence directional).

Each finding: evidence.observed quotes the page (the entity block or its absence); verification.reproduce is a runnable assertion/lookup; expected_impact is banded + confidence-tagged (no naked %).

Honesty

• A sameAs link does not force entry into the Knowledge Graph and produces no guaranteed ranking lift — it is a disambiguation signal, so impact is directional/ai, not established.
• Never fabricate, guess, or "best-effort" an identity URL to inflate entity density — a wrong sameAs actively misleads engines. Confirmed-only, or leave it as a TODO.