What we tested
Probed live on 23 Aug 2026 against rubric v1. 1 of 5 checks passed.
PROBE-VERIFIEDtier 2 of 3
—Markdown negotiationAccept: text/markdown
—Markdown twin at a predictable URL/page.md
—llms.txt/llms.txt
✓API catalogRFC 9727
—MCP server answers/.well-known/mcp/server-card.json → tools/list
What an agent could do here
Read from the page’s own content, with the wording each was drawn from. Inference is kept separate from tested facts — an agent completing the action is tier 3.
UNVERIFIED
register“Add to Chrome”
Context
11 sites in the index share the category browser extension, of which 5 are transactional.
How we grade
Three tiers. Every listing shows which one it has reached, and when. The rubric.
tier 1Declared
The site says agents are welcome in its robots.txt. A permission, not a capability.
tier 2Probe-verified
We fetched the site and tested each signal ourselves. Dated, repeatable, re-checked on a schedule.
tier 3Behaviourally verified
An agent completed the action end to end — booked, bought, submitted — and it worked.
Own this site?
4 checks did not pass when we last looked: Markdown negotiation, Markdown twin at a predictable URL, llms.txt, MCP server answers. Each is a small, specific fix; the rubric says exactly what we look for.
Behavioural verification — an agent completing your booking, purchase or contact flow end to end, with the date published here — opens to a small founding cohort first. Leave an email to be in it.
Related verified sites
Web2MDWeb2MD is a Chrome extension and CLI tool that converts webpages to clean Markdown optimiz
browser extension BirdTabBirdTab is a browser extension that replaces new tabs with daily bird photos, calls, facts
browser extension ToolbarDocumentation for installing Toolbar browser extension from the Chrome Web Store to share
browser extension ChronotabChronotab is a Chrome extension that schedules sets of tabs to open automatically at speci
browser extension TentcaleTentacle is a browser extension that enhances GitHub by adding contextual links in reposit
browser extension AutoDubAutoDub is a browser extension that translates and dubs YouTube videos into 42 languages w
browser extension Phrase FlipPhrase Flip is a free browser extension that replaces sentences on webpages with translati
browser extension Record generated from a live database query. Method: about the index.