v0.dev

AI agents can discover the site but lack structured documentation (llms.txt) and API specs to understand and interact with its full-stack development features.

21 pass · 6 warn · 2 fail · 13 n/a

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Discovery

22.2/22.2

Accessibility

29.6/33.3

Usability

20.1/44.4

Payments

n/a

Discovery 22.2/22.2

API reference linked from the homepagedetailsPASS
2 API link(s), e.g. /api/auth/login?next=%2F
Canonical URL declareddetailsPASS
https://v0.app
Documentation linked from the homepagedetailsPASS
1 docs link(s), e.g. /docs
Homepage has a meta descriptiondetailsPASS
98 characters
Homepage has a descriptive titledetailsPASS
'v0 by Vercel - Build Full-Stack Web Apps with AI' (48 chars)
Open Graph tags presentdetailsPASS
og:title and og:description present
robots.txt allows agent crawlersdetailsPASS
all 6 agent crawlers may fetch /
robots.txt existsdetailsPASS
HTTP 200, 138 bytes
robots.txt points at the sitemapdetailsPASS
robots.txt has a Sitemap: line
sitemap.xml exists and parsesdetailsPASS
5 URL(s) listed
Brand findable in agent searchdetailsN/A
search-based checks are deferred — excluded from the score
Listed in an MCP registrydetailsN/A
registry lookup not implemented in v1 — excluded from the score rather than guessed

Accessibility 29.6/33.3

llms.txt is structured markdowndetailsFAIL
/llms.txt returns HTML, not markdown
Fix: Serve /llms.txt as text/plain or text/markdown. An HTML error page at this path is worse than a 404: it looks like content.
Serves markdown when asked for itdetailsWARN
Accept: text/markdown → text/html; charset=utf-8
Fix: Optional but increasingly expected: honour `Accept: text/markdown` by serving a markdown rendering of the page, so agents skip HTML parsing entirely.
Content-to-markup ratio is reasonabledetailsWARN
ratio 0.004 — 3982 readable chars in 985403 bytes of HTML
Fix: Most of what you serve is markup and inline script rather than content. Reduce inline payloads or server-render more text so the signal-to-noise ratio favours readers.
Docs are readable without JavaScriptdetailsPASS
8635 characters of text at /docs
Homepage responds to an agent requestdetailsPASS
HTTP 200 for / (agent UA)
Served over HTTPSdetailsPASS
https://v0.app/
Structured data (JSON-LD) on the homepagedetailsPASS
1 valid block(s)
llms-full.txt is publisheddetailsPASS
HTTP 200, 990204 bytes
llms.txt is publisheddetailsPASS
HTTP 200, 985828 bytes
Links in llms.txt resolvedetailsPASS
1 sampled link(s) all resolve
Same response for agents and browsersdetailsPASS
both User-Agents got HTTP 200
Homepage has readable text without JavaScriptdetailsPASS
3982 characters of text in the served HTML
No long redirect chain on the homepagedetailsPASS
1 redirect(s)

Usability 20.1/44.4

OpenAPI document publisheddetailsFAIL
/openapi.json is served but is not valid JSON
Fix: Serve a parseable OpenAPI document at /openapi.json. What is there now cannot be read by any tooling.
agents.md is publisheddetailsWARN
/agents.md returns HTML
Fix: Serve /agents.md as markdown (text/markdown or text/plain). An HTML page here is probably your SPA catch-all route.
The /api root behaves predictablydetailsWARN
/api → HTTP 200 text/html; charset=utf-8
Fix: Serve JSON from API paths, with an accurate content-type.
Errors are machine-readabledetailsWARN
a nonexistent path returned HTTP 200, not 404
Fix: Return 404 for paths that do not exist. A 200 on a missing page makes an agent believe it found something.
.well-known/mcp.json advertises an MCP serverdetailsWARN
/.well-known/mcp.json not served (HTTP 404)
Fix: If you run an MCP server, advertise it at /.well-known/mcp.json so agents discover it without being told its URL.
A documentation endpoint respondsdetailsPASS
/docs → HTTP 200
MCP server completes the initialize handshakedetailsN/A
no MCP endpoint found to probe (none in the input URL and none advertised at /.well-known/mcp.json)
MCP tool parameters are typed and describeddetailsN/A
no listed MCP tools to inspect
Every MCP tool has a descriptiondetailsN/A
no listed MCP tools to inspect
MCP server lists toolsdetailsN/A
no MCP endpoint to probe
OpenAPI declares its auth schemedetailsN/A
no parseable OpenAPI document
OpenAPI operations are describeddetailsN/A
no parseable OpenAPI document
OpenAPI documents error responsesdetailsN/A
no parseable OpenAPI document
OpenAPI document is structurally validdetailsN/A
no parseable OpenAPI document

Payments not applicable — excluded from the score

Serves a 402 payment challengedetailsN/A
no agent-payment rail published — not applicable. This layer is excluded from the score rather than counted against the site.
Declares AP2 / ACP supportdetailsN/A
no agent-payment rail published — not applicable. This layer is excluded from the score rather than counted against the site.
Publishes x402 payment metadatadetailsN/A
no agent-payment rail published — not applicable. This layer is excluded from the score rather than counted against the site.

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