# State of Web Vitals (remote · www.corewebvitals.io)

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

- Trust score: 69/100 (medium)
- Change this week: +7
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `www.corewebvitals.io`: 69/100 (this document), [markdown](https://verifymcp.io/servers/corewebvitals-state-of-cwv/api-state-of-cwv-mcp.md), [page](https://verifymcp.io/servers/corewebvitals-state-of-cwv/api-state-of-cwv-mcp)

## Channel facts

- Endpoint: `https://www.corewebvitals.io/api/state-of-cwv/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `1.0.1`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 80/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - No authorisation is required to call this server. Every tool declares its destructiveHint and none is destructive, so open access doesn't expose one.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 55/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 1367 tokens (~455/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Capabilities**: 40/100
  - Spec-recency check failed: implements MCP spec 2025-03-26; the latest is 2026-07-28.

## Install

### Claude

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

### Codex

```toml
[mcp_servers.corewebvitals-state-of-cwv]
url = "https://www.corewebvitals.io/api/state-of-cwv/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "corewebvitals-state-of-cwv": {
      "type": "remote",
      "url": "https://www.corewebvitals.io/api/state-of-cwv/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add corewebvitals-state-of-cwv --url https://www.corewebvitals.io/api/state-of-cwv/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  corewebvitals-state-of-cwv:
    url: "https://www.corewebvitals.io/api/state-of-cwv/mcp"
```

### Other

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

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-03 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 68, +4)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-28 (score 63, +1)

No change was recorded against any check on this day. Stability & Change Management went from 3 to 7. That category is still filling its 30-day observation window: 1 days of observed history at the previous scan, 2 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 62, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 61)

First indexed and scored.

## MCP tools (3)

### `get_metrics` (~416 tokens)

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
\- 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.

Input parameters:

- `filter` (object): 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; pr…
- `focus` (string): CWV used when correlating technique metrics. Default: lcp.
- `group_by` (string): Break results down by this dimension: cms, frameworks, cdn, or a provider category (analytics, tag_managers, …). Omit for a single aggregate.
- `limit` (integer): Max groups or top categories. Default: 25, max: 100.
- `metrics`: Metrics to return. Default: lcp,inp,cls,ttfb,good_all3. String (comma-separated) or array of strings.
- `min_sites` (integer): When group_by is set, drop groups with fewer sites. Default: 50.

### `get_histogram` (~188 tokens)

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.

Input parameters:

- `filter` (object): 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; pr…
- `metric` (string, required): lcp | inp | cls | fcp | ttfb, or a contract scalar path.

### `list_options` (~90 tokens)

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.

Input parameters:

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

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/corewebvitals-state-of-cwv/api-state-of-cwv-mcp#diagnostics

## Score history

- 2026-08-03: 69
- 2026-08-02: 68
- 2026-08-01: 68
- 2026-07-31: 68
- 2026-07-30: 64
- 2026-07-29: 63
- 2026-07-28: 63
- 2026-07-27: 62
- 2026-07-26: 61

## Links

- Remote endpoint: https://www.corewebvitals.io/api/state-of-cwv/mcp
- Repository: https://github.com/corewebvitals/state-of-cwv-mcp
- Website: https://www.corewebvitals.io/state-of-cwv
- Changelog RSS feed: https://verifymcp.io/servers/corewebvitals-state-of-cwv/api-state-of-cwv-mcp/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/corewebvitals-state-of-cwv/api-state-of-cwv-mcp/changelog.json
- HTML version of this page: https://verifymcp.io/servers/corewebvitals-state-of-cwv/api-state-of-cwv-mcp