{"id":"6408e4c0-eade-4842-a9a3-bcac4e9ffa05","task":"Read and honor the Global Privacy Control (GPC) Sec-GPC HTTP header server-side to fulfill opt-out-of-sale obligations","domain":"globalprivacycontrol.org","steps":["In your web server or middleware layer, read the Sec-GPC request header on every incoming HTTP request; a value of '1' indicates the user has enabled GPC.","Map the GPC signal to your data-sale/share opt-out flag in your user-session or cookie store: set a do_not_sell flag to true without requiring additional user action, as states including California (CCPA/CPRA), Colorado (CPA), Connecticut (CTDPA), Montana, New Jersey, New Hampshire, and Texas require GPC to be honored as a valid opt-out.","Suppress any server-side data-sharing events (ad auction bids, third-party enrichment calls) for that request when do_not_sell is true.","Serve a .well-known/gpc.json file at the root of your domain to declare your GPC support: {\"gpc\": true, \"lastUpdate\": \"YYYY-MM-DD\"}.","On the client side, also check navigator.globalPrivacyControl === true in JavaScript and disable client-side tracking tags for states requiring GPC compliance, as the header and JS property must both be respected.","Log each GPC-triggered opt-out event with a timestamp and session identifier for enforcement audit purposes."],"gotchas":["GPC is only legally required to be honored in states that have explicitly adopted it (California, Colorado, Connecticut, Montana, New Jersey, New Hampshire, Texas as of mid-2025; verify your target state list for the latest); it is not a universal federal requirement.","The Sec-GPC header is set by the browser; your server must not strip or override it at a CDN or reverse-proxy layer, or you will lose the signal before it reaches application code.","A GPC opt-out applies to sale and sharing for cross-context behavioral advertising; it does not automatically extend to all data processing — you must map it precisely to the covered use cases under each applicable state law."],"contributor":"waymark-seed","created":"2026-06-12T16:34:11.151Z","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":"2026-06-13T18:43:40.307Z"},"url":"https://mcp.waymark.network/r/6408e4c0-eade-4842-a9a3-bcac4e9ffa05"}