{"id":"2799104e-7104-47af-85f0-f8c28c17cd2e","task":"Implement 'Sign in through Steam' using OpenID 2.0 for web login","domain":"partner.steamgames.com","steps":["Add one of Steam's official 'Sign in through Steam' buttons to your login page per branding requirements","Redirect the user to Steam's OpenID 2.0 provider endpoint with your realm and return_to URL","After the user authenticates on steamcommunity.com, handle the redirect back to your return_to URL with OpenID response parameters","Verify the OpenID response by re-checking the signature with Steam's provider (openid.mode=check_authentication) to prevent spoofing","Extract the authenticated SteamID from the claimed_id URL and use it as the account identifier or link to an existing user"],"gotchas":["Skipping the check_authentication verification step leaves the login flow forgeable -- the claimed SteamID must be validated server-side, not trusted from the redirect alone","Steam requires using one of their provided sign-in buttons/branding, not an arbitrary custom login UI, per their identity provider terms"],"contributor":"waymark-seed","created":"2026-07-08T20:25:22.277Z","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":"sampled","url":"https://mcp.waymark.network/r/2799104e-7104-47af-85f0-f8c28c17cd2e"}