diff --git a/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.cs b/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.cs
index c5265080..43dbffd6 100644
--- a/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.cs
+++ b/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationHandlers.cs
@@ -635,7 +635,7 @@ public static partial class OpenIddictClientWebIntegrationHandlers
             = OpenIddictClientHandlerDescriptor.CreateBuilder<ProcessAuthenticationContext>()
                 .AddFilter<RequireTokenRequest>()
                 .UseSingletonHandler<OverrideScope>()
-                .SetOrder(AttachTokenRequestParameters.Descriptor.Order + 250)
+                .SetOrder(AttachTokenRequestParameters.Descriptor.Order - 500)
                 .SetType(OpenIddictClientHandlerType.BuiltIn)
                 .Build();
 
@@ -647,14 +647,13 @@ public static partial class OpenIddictClientWebIntegrationHandlers
                 throw new ArgumentNullException(nameof(context));
             }
 
-            Debug.Assert(context.TokenRequest is not null, SR.GetResourceString(SR.ID4008));
-
             // osu! requires that the scope must be "public" for client credentials
             // grant, as other scopes have no meaningful effect.
             if (context.GrantType is GrantTypes.ClientCredentials &&
                 context.Registration.ProviderType is ProviderTypes.Osu)
             {
-                context.TokenRequest.Scope = "public";
+                context.Scopes.Add("public");
+                // TODO: how does user code add custom scopes here?
             }
 
             return ValueTask.CompletedTask;
@@ -963,7 +962,7 @@ public static partial class OpenIddictClientWebIntegrationHandlers
                 // Note: these providers don't have a static userinfo endpoint attached to their configuration
                 // so OpenIddict doesn't, by default, send a userinfo request. Since a dynamic endpoint is later
                 // computed and attached to the context, the default value MUST be overridden to send a request.
-                ProviderTypes.Dailymotion or ProviderTypes.HubSpot or
+                ProviderTypes.Dailymotion or ProviderTypes.HubSpot or ProviderTypes.Osu or
                 ProviderTypes.SuperOffice or ProviderTypes.Zoho
                     when context.GrantType is GrantTypes.AuthorizationCode or GrantTypes.DeviceCode or
                                               GrantTypes.Implicit          or GrantTypes.Password   or
@@ -1099,6 +1098,13 @@ public static partial class OpenIddictClientWebIntegrationHandlers
                         left : new Uri("https://api.hubapi.com/oauth/v1/access-tokens", UriKind.Absolute),
                         right: new Uri(token, UriKind.Relative)),
 
+                // osu! supports specifying a game mode when querying the userinfo endpoint.
+                ProviderTypes.Osu
+                    => !context.Properties.TryGetValue(Osu.Properties.GameMode, out string? gameMode) ||
+                        string.IsNullOrEmpty(gameMode) ?
+                            new Uri("https://osu.ppy.sh/api/v2/me", UriKind.Absolute) :
+                            new Uri($"https://osu.ppy.sh/api/v2/me/{gameMode}", UriKind.Absolute),
+
                 // SuperOffice doesn't expose a static OpenID Connect userinfo endpoint but offers an API whose
                 // absolute URI needs to be computed based on a special claim returned in the identity token.
                 ProviderTypes.SuperOffice when
diff --git a/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationProviders.xml b/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationProviders.xml
index c3fe7c59..a1cf813d 100644
--- a/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationProviders.xml
+++ b/src/OpenIddict.Client.WebIntegration/OpenIddictClientWebIntegrationProviders.xml
@@ -1759,8 +1759,7 @@
             Documentation="https://osu.ppy.sh/docs/index.html#authentication">
     <Environment Issuer="https://osu.ppy.sh/">
       <Configuration AuthorizationEndpoint="https://osu.ppy.sh/oauth/authorize"
-                     TokenEndpoint="https://osu.ppy.sh/oauth/token"
-                     UserInfoEndpoint="{(string.IsNullOrEmpty(settings.GameMode) ? 'https://osu.ppy.sh/api/v2/me' : $'https://osu.ppy.sh/api/v2/me/{settings.GameMode}')}">
+                     TokenEndpoint="https://osu.ppy.sh/oauth/token">
         <GrantType Value="authorization_code" />
         <GrantType Value="client_credentials" />
         <GrantType Value="refresh_token" />
@@ -1773,8 +1772,7 @@
     <Constant Class="GameMode" Value="fruits" Name="Catch"   />
     <Constant Class="GameMode" Value="mania"  Name="Mania"    />
 
-    <Setting PropertyName="GameMode" ParameterName="mode" Type="String" Required="false"
-             Description="The game mode to retrieve statistics for (e.g., 'osu', 'taiko', 'fruits', 'mania'). User default mode will be used if not specified" />
+    <Property Name="GameMode" DictionaryKey=".game_mode" />
   </Provider>
 
   <!--