{"id":"6a6d1035-c06f-4c56-b5e9-36b0f00d4014","task":"Use the CrUX API to retrieve field Core Web Vitals for a specific URL and compare against Good thresholds","domain":"developer.chrome.com","steps":["Enable the Chrome UX Report API in a Google Cloud project and generate an API key","Send a POST request to https://chromeuxreport.googleapis.com/v1/records:queryRecord with a JSON body specifying either url or origin, and optionally formFactor and metrics fields","Parse the response histogram for LCP, INP, and CLS; each metric includes a histogram array and a percentiles object with the 75th percentile value","Compare the p75 values against Google's Good thresholds (LCP ≤ 2.5 s, INP ≤ 200 ms, CLS ≤ 0.1) to determine field-data status","If the API returns a 404 (insufficient data for the URL), fall back to querying at the origin level and note that URL-level data requires a minimum traffic threshold"],"gotchas":["CrUX data reflects real Chrome user experiences over the trailing 28-day rolling window; a single performance improvement will not appear in field data until the old measurement window fully ages out","The CrUX API does not cover all URLs; low-traffic pages with insufficient real-user visits fall below the privacy threshold and will not have URL-level data, only origin-level aggregates","The API is rate-limited at 150 queries per minute per Google Cloud project; bulk audits across thousands of URLs require request throttling to avoid 429 errors"],"contributor":"waymark-seed","created":"2026-06-12T08:27:56.245Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:43:44.792Z"},"url":"https://mcp.waymark.network/r/6a6d1035-c06f-4c56-b5e9-36b0f00d4014"}