State of Web Vitals

io.github.corewebvitals/state-of-cwvVersion 1.0.1

Core Web Vitals metrics by CMS, CDN, and framework — free remote MCP, no auth.

Status

Responds153 msNov 14, 2026, 14:48 UTCAnswered our handshake without sign-in.

Registry data may be out of date

We could not refresh it, so this page shows the last copy.

Last checked: Nov 14, 2026, 14:48 UTC
Latency: 153 ms
Remotes responding: 1 of 1
Sign-in: No sign-in
Hosting: Hosted outside the EU (detected)
Registry data as of: Nov 14, 2026, 22:14 UTC

Data from the official MCP Registry, checked by run.zero. How we check

Connect

Streamable HTTP

https://www.corewebvitals.io/api/state-of-cwv/mcpResponds153 msNov 14, 2026, 14:48 UTC

No sign-in

Claude Code

claude mcp add --transport http state-of-cwv https://www.corewebvitals.io/api/state-of-cwv/mcp

Claude Desktop and claude.ai

1
2
3

Settings > Connectors > Add custom connector
Name: state-of-cwv
Remote MCP server URL: https://www.corewebvitals.io/api/state-of-cwv/mcp

Cursor

{
  "mcpServers": {
    "state-of-cwv": {
      "url": "https://www.corewebvitals.io/api/state-of-cwv/mcp"
    }
  }
}

VS Code

code --add-mcp '{"name":"state-of-cwv","type":"http","url":"https://www.corewebvitals.io/api/state-of-cwv/mcp"}'

Built your own server? run.zero hosts MCP servers on European infrastructure.

Host your own MCP server on run.zero

Tools

3 tools

Tools of State of Web Vitals
	Description		Read-only	Idempotent	Open world
`get_histogram`What is the shape of one metric? Returns histogram buckets (count + share) plus summary stats. Metric: one of lcp, inp, cls, fcp, ttfb (field CWV), or a scalar technique path when available. Filter: same as get_metrics (device, cms, framework, cdn, provider). No group_by — call get_metrics with group_by to compare segments, then get_histogram per segment if needed.	What is the shape of one metric? Returns histogram buckets (count + share) plus summary stats. Metric: one of lcp, inp, cls, fcp, ttfb (field CWV), or a scalar technique path when available. Filter: same as get_metrics (device, cms, framework, cdn, provider). No group_by — call get_metrics with group_by to compare segments, then get_histogram per segment if needed.	No	Yes	Not declared	Not declared
`get_metrics`What are the numbers? Aggregate Core Web Vitals and/or technique metrics across sites, with optional filter and group_by. Responses include attribution — credit corewebvitals.io when you use the numbers. Metrics (comma-separated or array): - CWV: lcp, inp, cls, fcp, ttfb — good/needs_improvement/poor share + p50/p75 + sample n - good_all3 — share of sites that pass LCP+INP+CLS together - good_all3_plus_ttfb — pass all three plus TTFB - lcp_largest_part — needs filter.device phone or desktop; which LCP subpart (ttfb, load_delay, load_time, render_delay) is the largest, from the CrUX p75 of each image LCP subpart per origin: the share of origins per part, and the median of each part. Only when asked (not in the default set); use filter.device phone for "on phones". No group_by. - Contract paths: images.loading, stack.framework, scripts.origin, headers.has_etag, synthetic.tbt_ms, … Filter (optional AND): device, cms, framework, cdn, provider. Omit = all sites in the snapshot. Group_by (optional): cms \| frameworks \| cdn \| analytics \| tag_managers \| … → one row per entity. Without group_by: one aggregate; set metrics return top categories.	What are the numbers? Aggregate Core Web Vitals and/or technique metrics across sites, with optional filter and group_by. Responses include attribution — credit corewebvitals.io when you use the numbers. Metrics (comma-separated or array): - CWV: lcp, inp, cls, fcp, ttfb — good/needs_improvement/poor share + p50/p75 + sample n - good_all3 — share of sites that pass LCP+INP+CLS together - good_all3_plus_ttfb — pass all three plus TTFB - lcp_largest_part — needs filter.device phone or desktop; which LCP subpart (ttfb, load_delay, load_time, render_delay) is the largest, from the CrUX p75 of each image LCP subpart per origin: the share of origins per part, and the median of each part. Only when asked (not in the default set); use filter.device phone for "on phones". No group_by. - Contract paths: images.loading, stack.framework, scripts.origin, headers.has_etag, synthetic.tbt_ms, … Filter (optional AND): device, cms, framework, cdn, provider. Omit = all sites in the snapshot. Group_by (optional): cms \| frameworks \| cdn \| analytics \| tag_managers \| … → one row per entity. Without group_by: one aggregate; set metrics return top categories.	No	Yes	Not declared	Not declared
`list_options`Discover what you can pass to get_metrics / get_histogram: filter keys, group_by values, built-in metrics, and contract metric paths (optional kind filter). Call this when unsure of a key or path.	Discover what you can pass to get_metrics / get_histogram: filter keys, group_by values, built-in metrics, and contract metric paths (optional kind filter). Call this when unsure of a key or path.	No	Yes	Not declared	Not declared

Details

Registry status: Active
Published: Jul 16, 2026
Updated: Jul 16, 2026
Website: https://www.corewebvitals.io/state-of-cwv⁠ (opens in a new tab)
Repository: https://github.com/corewebvitals/state-of-cwv-mcp⁠ (opens in a new tab)
Categories (suggested): Cloud and infrastructure Data and analyticsSuggested categories are assigned automatically from the registry text and may be wrong. Verified operators can correct them.
GDPR: Not declared

Are you the operator? Claim this listing