Core Web Vitals MCP Server
Server Configuration
Describes the environment variables required to run the server.
| Name | Required | Description | Default |
|---|---|---|---|
| CRUX_API_KEY | No | Alternative Google API Key for CrUX API | |
| DO_NOT_TRACK | No | Set to 1 to opt out of telemetry | |
| GOOGLE_API_KEY | No | Google API Key for Chrome UX Report (CrUX) and PageSpeed Insights APIs | |
| DISABLE_TELEMETRY | No | Set to 1 to disable telemetry | |
| MCP_TELEMETRY_OPT_OUT | No | Set to 1 to opt out of telemetry | |
| CORE_WEB_VITALS_TELEMETRY | No | Set to false to disable telemetry |
Instructions
Guidance the server publishes about itself, which clients place ahead of the tool catalog so the model reads it before choosing anything.
This server publishes no instructions, or was last inspected before Glama recorded them.
Capabilities
Features and capabilities supported by this server
Protocol revision2025-11-25
| Capability | Details |
|---|---|
| tools | {
"listChanged": false
} |
| prompts | {
"listChanged": false
} |
| resources | {
"subscribe": false,
"listChanged": false
} |
Tools
Functions exposed to the LLM to take actions
| Name | Description |
|---|---|
| get_crux_metricsA | Query Google Chrome User Experience Report (CrUX) API for real-user field metrics. Returns 75th percentile ratings for LCP, INP, CLS, FCP, TTFB, and overall Core Web Vitals assessment. Args: url: Page URL (e.g. 'https://surendranb.com/blog/article') or root origin ('https://surendranb.com'). form_factor: Device form factor filter ('ALL_FORM_FACTORS', 'PHONE', 'DESKTOP', 'TABLET'). Defaults to ALL_FORM_FACTORS. api_key: Optional Google API Key. If omitted, checks GOOGLE_API_KEY or CRUX_API_KEY environment variables. |
| get_crux_historyA | Query Google Chrome UX Report History API for 28-day historical field metric trends. Provides timeseries percentiles for LCP, INP, CLS, FCP, and TTFB across 25+ weekly collection periods. Args: url_or_origin: Web page URL or origin domain (e.g. 'https://surendranb.com'). api_key: Optional Google API Key. If omitted, checks GOOGLE_API_KEY or CRUX_API_KEY environment variables. |
| audit_pagespeedB | Run a Google PageSpeed Insights lab audit for synthetic Lighthouse performance scores and diagnostics. Returns overall performance score (0-100), Speed Index, Total Blocking Time (TBT), Largest Contentful Paint (LCP), and prioritized remediation opportunities. Args: url: URL of the web page to audit (e.g. 'https://surendranb.com'). strategy: Analysis strategy ('mobile' or 'desktop'). Defaults to 'mobile'. api_key: Optional Google API Key. If omitted, checks GOOGLE_API_KEY or PAGESPEED_API_KEY. |
| doctorB | Validate Google Cloud API credentials, test endpoint reachability, and check test beds. Args: api_key: Optional Google API Key to test directly. |
| skills_listA | List available Core Web Vitals diagnostic and remediation playbooks (LCP, INP, CLS). |
| skill_readA | Read a specialized Core Web Vitals optimization playbook (e.g. 'lcp-optimization', 'inp-debugging', 'cls-remediation'). Args: name: Name of the skill to read. Call skills_list to view available playbooks. |
| check_for_updatesC | Check PyPI for the latest version of core-web-vitals-mcp. |
Prompts
Interactive templates invoked by user choice
| Name | Description |
|---|---|
No prompts | |
Resources
Contextual data attached and managed by the client
| Name | Description |
|---|---|
No resources | |
TDQS
Scored across 7 tools
Each tool targets a distinct purpose: field metrics vs. historical trends vs. lab audit vs. credential diagnostics vs. playbook browsing vs. version checking. get_crux_metrics and get_crux_history are clearly separated by snapshot vs. time-series intent. skills_list and skill_read are cleanly distinguished by listing vs. reading.
Conventions are mixed: get_crux_metrics/get_crux_history use verb_noun, audit_pagespeed uses a different verb, skills_list/skill_read reverse to noun_verb (and inconsistently pluralize), while 'doctor' and 'check_for_updates' follow yet other patterns. Still readable, but no single predictable scheme.
Seven tools is well-scoped for a focused Core Web Vitals analysis server, with core analysis (CrUX current/history, PageSpeed), guidance (skills), and utilities (doctor, update check). No bloat or conspicuous omission.
Covers the domain well: real-user field data, historical trends, and synthetic lab audits plus remediation playbooks. Minor gaps include no batch/multi-URL comparison and no direct competitor/origin-vs-page aggregation, but core workflows are addressed.