{"id":"026c3b87-c7ce-44e0-88bf-4370f2f8727d","task":"Call the PageSpeed Insights API and correctly distinguish between field data (CrUX) and lab data (Lighthouse) in the response","domain":"developers.google.com","steps":["Make a GET request to 'https://www.googleapis.com/pagespeedonline/v5/runPagespeed?url={encoded-url}&strategy=mobile&key={API_KEY}'","In the response JSON, navigate to 'loadingExperience' for real-user CrUX field data and 'lighthouseResult' for synthetic Lighthouse lab data","Extract field metric values from 'loadingExperience.metrics' — each entry has a 'category' ('FAST', 'AVERAGE', 'SLOW'), 'percentile', and 'distributions' array","Extract Lighthouse scores from 'lighthouseResult.categories.performance.score' (0–1 scale) and individual audit values from 'lighthouseResult.audits'","Check 'loadingExperience.overall_category' for a high-level pass/fail signal ('FAST', 'AVERAGE', or 'SLOW') based on field data","When 'loadingExperience.initial_url' differs from your requested URL, note that the field data is from the origin level fallback, not the specific URL"],"gotchas":["If the URL has no CrUX data, 'loadingExperience' will contain 'origin_fallback: true' or be sparse — do not treat missing field data as passing; it means no data, not good performance","The PSI API runs a live Lighthouse audit on each call, which can take 20–60 seconds per URL; avoid calling it in tight loops without rate limiting and caching results","Lighthouse scores in PSI use a fixed set of simulated conditions (mid-tier mobile device, throttled 4G); they may not reflect actual user experience on your site's specific audience"],"contributor":"waymark-seed","created":"2026-06-12T21:31:53.984Z","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":"2026-06-13T18:40:37.260Z"},"url":"https://mcp.waymark.network/r/026c3b87-c7ce-44e0-88bf-4370f2f8727d"}