io.github.corewebvitals/state-of-cwv — Model Context Protocol (MCP) Server

This free remote MCP server provides Core Web Vitals metrics collected by CMS, CDN, and framework. It exposes the same numbers as the public State of Web Vitals explorer and is based on Chrome field data plus a multi-site crawl, delivered via Streamable HTTP without authentication.

🛠️ Key Features

Core Web Vitals metrics by CMS, CDN, and framework
Chrome field data with multi-site crawl
Same figures as the public State of Web Vitals explorer
Remote access via Streamable HTTP (toolCount: 3)

🚀 Use Cases

Compare Core Web Vitals performance across CMS, CDN, and framework
Use explorer-aligned metrics in MCP-based workflows

⚡ Developer Benefits

No auth required
Preferred connection URL: https://www.corewebvitals.io/api/state-of-cwv/mcp
Topics include: core-web-vitals, lcp, mcp, model-context-protocol, streamable-http, web-performance

⚠️ Limitations

Tooling details beyond “toolCount: 3” are not specified in the provided source data.

{ "type": "object", "properties": { "metrics": { "description": "Metrics to return. Default: lcp,inp,cls,ttfb,good_all3. String (comma-separated) or array of strings." }, "filter": { "type": "object", "description": "AND filters. Omit for all sites in the dataset. Keys: device (all|phone|desktop), cms, framework, cdn, provider (key), provider_category (e.g. analytics — use with provider or alone is not enough; prefer group_by for rankings).", "properties": { "device": { "type": "string", "enum": [ "all", "phone", "desktop" ], "description": "CrUX device slice. Default: all." }, "cms": { "type": "string", "description": "Only sites on this CMS key (wordpress, shopify, wix, …)." }, "framework": { "type": "string", "description": "Only sites that include this JS framework key (react, vue, jquery, …)." }, "cdn": { "type": "string", "description": "Only sites on this CDN key (cloudflare, origin, …)." }, "provider": { "type": "string", "description": "Only sites that load this third-party provider key (google_analytics_4, …)." } }, "additionalProperties": false }, "group_by": { "type": "string", "description": "Break results down by this dimension: cms, frameworks, cdn, or a provider category (analytics, tag_managers, …). Omit for a single aggregate." }, "focus": { "type": "string", "enum": [ "lcp", "inp", "cls", "fcp", "ttfb" ], "description": "CWV used when correlating technique metrics. Default: lcp." }, "limit": { "type": "integer", "description": "Max groups or top categories. Default: 25, max: 100." }, "min_sites": { "type": "integer", "description": "When group_by is set, drop groups with fewer sites. Default: 50." } } }

{ "type": "object", "properties": { "metric": { "type": "string", "description": "lcp | inp | cls | fcp | ttfb, or a contract scalar path." }, "filter": { "type": "object", "description": "AND filters. Omit for all sites in the dataset. Keys: device (all|phone|desktop), cms, framework, cdn, provider (key), provider_category (e.g. analytics — use with provider or alone is not enough; prefer group_by for rankings).", "properties": { "device": { "type": "string", "enum": [ "all", "phone", "desktop" ], "description": "CrUX device slice. Default: all." }, "cms": { "type": "string", "description": "Only sites on this CMS key (wordpress, shopify, wix, …)." }, "framework": { "type": "string", "description": "Only sites that include this JS framework key (react, vue, jquery, …)." }, "cdn": { "type": "string", "description": "Only sites on this CDN key (cloudflare, origin, …)." }, "provider": { "type": "string", "description": "Only sites that load this third-party provider key (google_analytics_4, …)." } }, "additionalProperties": false } }, "required": [ "metric" ] }

{ "type": "object", "properties": { "kind": { "type": "string", "description": "Optional contract kind: scalar, boolean, categorical, set, weighted_set, measures." }, "include_paths": { "type": "boolean", "description": "Include full contract path list. Default true." } } }

Connect (preferred)

URL: https://www.corewebvitals.io/api/state-of-cwv/mcp
Auth: none
Transport: Streamable HTTP
Registry: io.github.corewebvitals/state-of-cwv

Claude Code

bash

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

Cursor / Grok / other clients

json

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

Curl

bash

curl -s -X POST https://www.corewebvitals.io/api/state-of-cwv/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"get_metrics","arguments":{"metrics":"lcp,good_all3","group_by":"cms","min_sites":100}}}'

Tool

Purpose

get_metrics

Aggregates and optional group_by rankings (CMS, CDN, frameworks, …)

get_histogram

Distribution buckets for one metric under an optional filter

list_options

Discover filters, group_by values, and metric paths

Place

Link

Official MCP Registry

io.github.corewebvitals/state-of-cwv

Glama

https://glama.ai/mcp/servers/corewebvitals/state-of-cwv-mcp

Glama connector

https://glama.ai/mcp/connectors/io.github.corewebvitals/state-of-cwv

Smithery

https://smithery.ai/servers/corewebvitals/state-of-cwv

Explorer

https://www.corewebvitals.io/state-of-cwv/explorer

Methodology

https://www.corewebvitals.io/state-of-cwv/methodology

Discovery JSON

https://www.corewebvitals.io/.well-known/mcp.json

Install

Tools (3)

get_metricsget_histogramlist_options

Remote endpoint

Streamable HTTP

Hosted server - connect over the network, no local install.

url

https://www.corewebvitals.io/api/state-of-cwv/mcp

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "state-of-cwv": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://www.corewebvitals.io/api/state-of-cwv/mcp"
      ]
    }
  }
}

Desktop config is stdio-only; this bridges via mcp-remote. Native remote: Settings > Connectors.

State of Web Vitals

io.github.corewebvitals/state-of-cwv — Model Context Protocol (MCP) Server

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

⚠️ Limitations

Topics

get_metrics

get_histogram

list_options

State of Web Vitals MCP

Connect (preferred)

Claude Code

Cursor / Grok / other clients

Curl

Tools

What this is

Attribution

Discovery

Local stdio / Docker (directories & inspectors)

License

Install

Remote endpoint

Related servers

metrics	any	optional	Metrics to return. Default: lcp,inp,cls,ttfb,good_all3. String (comma-separated) or array of strings.
filter	object	optional	AND filters. Omit for all sites in the dataset. Keys: device (all\|phone\|desktop), cms, framework, cdn, provider (key), provider_category (e.g. analytics — use with provider or alone is not enough; prefer group_by for rankings).
group_by	string	optional	Break results down by this dimension: cms, frameworks, cdn, or a provider category (analytics, tag_managers, …). Omit for a single aggregate.
focus	string	optional	CWV used when correlating technique metrics. Default: lcp.
limit	integer	optional	Max groups or top categories. Default: 25, max: 100.
min_sites	integer	optional	When group_by is set, drop groups with fewer sites. Default: 50.

metric	string	required	lcp \| inp \| cls \| fcp \| ttfb, or a contract scalar path.
filter	object	optional	AND filters. Omit for all sites in the dataset. Keys: device (all\|phone\|desktop), cms, framework, cdn, provider (key), provider_category (e.g. analytics — use with provider or alone is not enough; prefer group_by for rankings).

kind	string	optional	Optional contract kind: scalar, boolean, categorical, set, weighted_set, measures.
include_paths	boolean	optional	Include full contract path list. Default true.