| name | crux-metrics |
| description | Pulls Chrome User Experience Report (CrUX) metrics to get historical, real-world user experience data for URLs and origins. Do NOT use for immediate feedback on local code changes. |
CrUX Metrics Skill
This skill allows you to query the Chrome User Experience Report (CrUX) API for real-world field data regarding performance metrics (like LCP, CLS, INP, FCP, TTFB).
Critical Constraints
- Historical Data Only: CrUX is 28-day rolling field data. Do not use this skill to check the immediate impact of code changes. For immediate feedback on a change you just made, use Lighthouse or a local performance tool instead.
Authentication
This skill requires a CrUX API key.
- Check if the
CRUX_API_KEY environment variable is set.
- If it is NOT set, you MUST ask the user to provide one or set it themselves by running:
export CRUX_API_KEY="your_api_key" in their terminal before proceeding.
Usage
Run the Node.js script to query metrics:
node scripts/query_crux.cjs [options]
Options
--url <url> : Query for a specific page URL. (Mutually exclusive with origin)--origin <origin> : Query for an entire origin (e.g., https://example.com).--form-factor <factor> : (Optional) DESKTOP, PHONE, or TABLET.--ect <ect> : (Optional) Effective connection type, e.g., 4G, 3G.--history : (Optional) Query the History API for 25-week trend data instead of the standard 28-day snapshot.
Example
node scripts/query_crux.cjs --url https://developer.chrome.com --form-factor DESKTOP
