set_canonical: Agent-Applied rel=canonical Changes

set_canonical is the tool the Get AI Traffic agent uses to set a page’s rel="canonical" URL after you approve a fix. It names the URL you want treated as the real one for a piece of content, then publishes the tag through your site’s connection.

This page documents what the tool touches, what it refuses to touch, and how to undo it. For the decision of whether a page should point its canonical at itself or somewhere else, read Missing rel Canonical Tags Let AI Cite the Wrong Version of Your Page. That question is a judgment call. This page is about the mechanics.

What it does

When you approve a missing_canonical action item, the agent adds a <link rel="canonical" href="..."> to the page head pointing at the absolute URL you want indexed. On WordPress the canonical follows whichever plugin owns your SEO title: if Yoast owns the title, the value is written to Yoast’s canonical field, so you get one tag instead of two competing ones. Otherwise the Get AI Traffic plugin stores the value and emits the tag through a wp_head fallback, which also suppresses WordPress core’s auto-generated canonical. That routing starts from the site’s platform configuration, and a site with no configuration detected falls back to the plugin. The plugin gets the final say, though: it checks whether Yoast is actually running and writes Yoast’s canonical field when it is, whatever the stored configuration says.

Worth knowing before you rely on it: the canonical is a hint, not a command. Google is explicit that indicating a canonical preference is a hint, not a rule. It consolidates duplicate signals onto one address, but the engine still weighs internal links, redirects, sitemaps, and what it actually renders before deciding which URL to show. This tool sets a strong, clear signal. It does not force the outcome.

What it will not touch

• The visible page. This tool writes head metadata only. It does not rewrite content or move the page.
• Your content and URLs. It adds one line naming the preferred URL. It does not create redirects, change the address, or alter the body.
• Other canonicalization signals. If your sitemap or your redirects already point elsewhere, this tool sets the tag it was told to set. It does not reconcile a conflict between the tag and those other signals for you.

Timing

The tag is written to your site immediately, but search engines only re-read it on their next crawl, and then still take time to consolidate the duplicate URLs onto the one you named. Expect this to settle over crawls, not the same day.

Rolling back

Every applied change is written to the ledger with the prior canonical. roll_back restores the previous value exactly, whether that was a different canonical URL or no tag at all.

Related tools

• purge_cache runs after an apply, so a cached copy of the old page does not keep serving the old canonical at the edge.
• set_indexing controls noindex at the page level, a different mechanism. A canonical tells engines which URL to prefer among duplicates; noindex tells them not to list a page at all. Use noindex to drop a page from search, not a canonical.

Findings this tool resolves

• missing_canonical: a page has no rel="canonical" annotation, so the crawler is left to choose which URL represents the content.