keystone/api-ref/source/v3-ext/federation/service-provider/samples/register-request.json

{
    "service_provider": {
        "auth_url": "https://example.com/identity/v3/OS-FEDERATION/identity_providers/acme/protocols/saml2/auth",
        "description": "Remote Service Provider",
        "enabled": true,
        "sp_url": "https://example.com/identity/Shibboleth.sso/SAML2/ECP"
    }
}