The Sitemap line in robots.txt is the one place every crawler looks without being asked. Leaving it out means relying on each engine being told separately. Submitting a sitemap through each search engine's own panel works, and stops working the moment a new engine matters or an account changes hands. The line in robots.txt is the version that keeps working without anyone remembering it, and it is the only discovery route the crawlers behind AI answers reliably follow.
The finding reads:
info robots-no-sitemap robots.txt names no Sitemap — the line `Sitemap: https://…/sitemap.xml` costs nothingAdd a `Sitemap:` line to robots.txt.
This is a site-level finding: it belongs to the site, not to any one page, and is reported once however many pages are audited.
pipx install indexgap
cd your-project
indexgap init
indexgap checkThen indexgap brief turns
every finding on this page into a work order in indexgap-briefs/,
with the thresholds the result has to satisfy and the command to check it.