Comprehension · image-alt
Agents cannot see images. Alt text is the only description they get.
| Check id | image-alt |
|---|---|
| Pillar | Comprehension — Once fetched, can the agent work out what this page is and what it says? |
| Weight within the pillar | 8 points |
| Share of the overall score | about 1.9 of 100 |
| Kind of change | Engineering — a code change and a deploy |
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.
Agents cannot see images. Alt text is the only description they get.
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.
Describe what each image shows. Use alt="" only for purely decorative images.
<img src="/chart.png" alt="AX scores of the top 100 SaaS sites, median 41 out of 100">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.
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 | 60 | 27% |
| Warned | 49 | 22% |
| Passed | 111 | 50% |
| Did not apply | 72 | excluded from the shares |
The last row is kept out of the percentages deliberately. A check that did not apply to 72 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 27% the web is genuinely split on this one, so it is neither table stakes nor a differentiator on its own.
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.
Agents cannot see images. Alt text is the only description they get. It sits in the Comprehension pillar of the Agent Experience rubric and is worth 8 points within that pillar, which works out at about 1.9 points of the overall score out of 100.
Describe what each image shows. Use alt="" only for purely decorative images. It is an engineering change rather than a setting, so it needs a deploy rather than an edit.
No. Of 220 public sites where this check applied, 60 failed it — 27%. The measurement was taken on 2026-09-06 against AX specification v1.5.1, and no site is named.
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.
Once fetched, can the agent work out what this page is and what it says?
See how your own page does on this check and the other 69, with the fixes ordered by how many points each one recovers. One scan, no account.