Rubric / Discoverability
Canonical URL
markup.canonical
weight 2deterministic
A canonical URL is declared and resolves to the same page.
Definition
Check ID
markup.canonical
Category
Discoverability
Weight
2
Counts toward the score
Yes.
Evaluated by
A fixed rule with no threshold of our choosing. The same input always produces the same verdict.
Standard maturity
established
Canonical spec
Introduced in
r2026.04.1
Retired in
Still active.
History
Every change to the instrument— including the versions that changed this check
Machine-readable
/rubric.json— this check, and every other, as data
How often this check is right
No rate published. Too few labelled cases to publish a rate: 2 flagged cases (30 needed to publish), 2 defective cases (30 needed to publish). The counts are the honest answer here. The matrix behind markup.canonical is 6 labelled cases — reported here rather than turned into a percentage that would read as more certain than the evidence is.
Corpus v1, measured under rubric r2026.11.0. Full method and every other check at /rubric/accuracy.
How to fix it
Add `<link rel="canonical" href="...">` to your primary pages. Agents use this to dedupe and cite.
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