Page analysis
What it is
The site check tells you whether AI can read your site at all. Page analysis tells you which of your individual pages are weak, and what would fix each one.
Why it matters
Think of your website as a class of children sitting an exam. "Did the class pass?" is a useful question. But it won't tell you that three children never turned up, two handed in a blank sheet, and one wrote a brilliant answer to the wrong question. Most websites are like that. The homepage is polished because everyone looks at it. Meanwhile a dozen other pages are thin, or duplicated, or about nothing in particular — and those are the ones quietly dragging you down and confusing anything trying to understand what you do.
What you do with it
You get a per-page score and a short list of what's actually wrong with that page — not generic advice, the specific problem on that page. Start at the bottom. The worst pages are usually the quickest to fix, and fixing a thin page is far cheaper than writing a new one.
A page we couldn't read — because it was blocked, or timed out — is reported as unreadable, not scored badly. Those are different problems and only one of them is yours to fix.