Comprehension — Once fetched, can the agent work out what this page is and what it says?
Weight within the pillar
6 points
Share of the overall score
about 1.4 of 100
Kind of change
Configuration or content — no engineering needed
Two numbers rather than one, because a check's weight is inside its pillar and the pillar is a share
of the whole. The largest check in the smallest pillar moves your score less than a middling one in
the largest, and knowing which you are looking at is the difference between fixing the right thing
and fixing the loudest thing.
Why an agent cares
Without a main landmark an extractor has to guess your content boundary heuristically, and on marketing pages it usually guesses the header.
Worth saying plainly: this is not a search-engine ranking factor and passing it will not move you up
a results page. It measures something else — whether software with no browser, no JavaScript
and a few hundred tokens of budget can tell what your page is and do something with it. Those are the
conditions an AI assistant reads you under, and they are much harsher than a browser's.
How to fix it
Wrap the primary content in <main>, and each self-contained item in <article>.
<main>
<article>
<h1>…</h1>
…
</article>
</main>
That remediation is the one the scanner itself offers when this check fails, read from the same code
that does the scoring rather than written alongside it. If it were typed out separately it could
drift from the check that judges it, which is the failure that makes published advice worthless.
How often the web fails this
Measured on 2026-09-06 against AX specification v1.5.1, across a
sample of 292 public websites.
Result
Sites
Share of those assessed
Failed
58
20%
Warned
29
10%
Passed
205
70%
Did not apply
0
excluded from the shares
The last row is kept out of the percentages deliberately. A check that did not apply to
0 of 292 sites is not a check most of the web passes, and folding those in is the
commonest way this sort of table is used to say something untrue.
At 20% this is something most sites already get right, which makes failing it more costly than the point value suggests — you are behind the field rather than level with it.
Testing it on your own site
npx axray-cli your-site.com
All 70 checks against one URL, this one among them, with what was found rather than only whether it
passed. Add --min 70 in a pipeline and the command exits non-zero below that score, so a
change that breaks what agents can read fails the build instead of shipping.
Questions about this check
What does the "Main content is marked as such" check mean?
Without a main landmark an extractor has to guess your content boundary heuristically, and on marketing pages it usually guesses the header. It sits in the Comprehension pillar of the Agent Experience rubric and is worth 6 points within that pillar, which works out at about 1.4 points of the overall score out of 100.
How do I fix landmarks?
Wrap the primary content in <main>, and each self-contained item in <article>. It is a configuration or content change rather than an engineering one, so it can usually ship the same day.
Is it unusual to fail landmarks?
No. Of 292 public sites where this check applied, 58 failed it — 20%. The measurement was taken on 2026-09-06 against AX specification v1.5.1, and no site is named.
How do I test landmarks on my own site?
Run npx axray-cli your-site.com from a terminal. It runs all 70 checks against one URL and prints this one among them, with what it found rather than only whether it passed. It is free, needs no account and installs nothing.
The rest of the Comprehension pillar
Once fetched, can the agent work out what this page is and what it says?