canonical.missing
No <link rel="canonical"> is present.
What to change
Add a self-referencing canonical with the absolute preferred URL (scheme, host, trailing slash) so duplicate URLs (query strings, www/non-www) consolidate to it.
The documentation on developers.google.comA finding of this rule on a page carries the exact edits for that page: the markup it quotes, and what to write instead.
When it runs
Runs on every SEO audit: of a page, a crawl, a build directory or HTML. A warning is a problem that costs a page ranking, clicks or citations. Each finding takes 5 points off the page's score.
The severity here is the rule's usual one: a finding can be raised or lowered when the page gives a reason.
Run it, or skip it
Check a page for this rule alone, after a fix for instance:
npx @rivi-software/agentic-seo-check audit https://example.com --rule canonical.missingOr from an assistant, with the MCP tool seo_audit_page:
{
"url": "https://example.com",
"rules": [
"canonical.missing"
]
}To leave it out of an audit, pass --disable canonical.missing on the command, or disableRules: ["canonical.missing"] to a tool.
More in Canonical URLs
All 8 rules- Error
canonical.header-conflictThe HTTP Link header names a different canonical URL than the page's <link rel="canonical">, or names more than one. - Error
canonical.multipleMore than one canonical link is present. When they disagree, search engines ignore all of them. - Error
canonical.invalidThe canonical href is empty or cannot be resolved to an http(s) URL. - Warning
canonical.relativeThe canonical href is a relative URL. - Warning
canonical.protocol-mismatchThe page is served over https but the canonical points to http. - Info
canonical.other-pageThe canonical points to a different URL, so search engines will treat this page as a duplicate of that URL. - Warning
canonical.paginated-to-firstPage 2 or later of a paginated series (?page=2, /page/2/) names the first page as its canonical, so search engines may drop it and miss the items only it links to.