Fix enum serialization

Author: zaevi

src/ModelContextProtocol/Client/McpClientExtensions.cs

@@ -485,7 +485,7 @@ public static Task SetLoggingLevel(this IMcpClient client, LoggingLevel level, C
         Throw.IfNull(client);
 
         return client.SendRequestAsync<EmptyResult>(
-            CreateRequest("logging/setLevel", new() { ["level"] = level.ToJsonValue() }),
+            CreateRequest("logging/setLevel", new() { ["level"] = level }),
             cancellationToken);
     }
 
@@ -514,22 +514,6 @@ private static JsonRpcRequest CreateRequest(string method, Dictionary<string, ob
         return parameters;
     }
 
-    private static string ToJsonValue(this LoggingLevel level)
-    {
-        return level switch
-        {
-            LoggingLevel.Debug => "debug",
-            LoggingLevel.Info => "info",
-            LoggingLevel.Notice => "notice",
-            LoggingLevel.Warning => "warning",
-            LoggingLevel.Error => "error",
-            LoggingLevel.Critical => "critical",
-            LoggingLevel.Alert => "alert",
-            LoggingLevel.Emergency => "emergency",
-            _ => throw new ArgumentOutOfRangeException(nameof(level))
-        };
-    }
-
     /// <summary>Provides an AI function that calls a tool through <see cref="IMcpClient"/>.</summary>
     private sealed class McpAIFunction(IMcpClient client, Tool tool) : AIFunction
     {

src/ModelContextProtocol/Protocol/Types/LoggingLevel.cs

@@ -10,34 +10,34 @@ namespace ModelContextProtocol.Protocol.Types;
 public enum LoggingLevel
 {
     /// <summary>Detailed debug information, typically only valuable to developers.</summary>
-    [JsonPropertyName("debug")]
+    [JsonStringEnumMemberName("debug")]
     Debug,
 
     /// <summary>Normal operational messages that require no action.</summary>
-    [JsonPropertyName("info")]
+    [JsonStringEnumMemberName("info")]
     Info,
 
     /// <summary>Normal but significant events that might deserve attention.</summary>
-    [JsonPropertyName("notice")]
+    [JsonStringEnumMemberName("notice")]
     Notice,
 
     /// <summary>Warning conditions that don't represent an error but indicate potential issues.</summary>
-    [JsonPropertyName("warning")]
+    [JsonStringEnumMemberName("warning")]
     Warning,
 
     /// <summary>Error conditions that should be addressed but don't require immediate action.</summary>
-    [JsonPropertyName("error")]
+    [JsonStringEnumMemberName("error")]
     Error,
 
     /// <summary>Critical conditions that require immediate attention.</summary>
-    [JsonPropertyName("critical")]
+    [JsonStringEnumMemberName("critical")]
     Critical,
 
     /// <summary>Action must be taken immediately to address the condition.</summary>
-    [JsonPropertyName("alert")]
+    [JsonStringEnumMemberName("alert")]
     Alert,
 
     /// <summary>System is unusable and requires immediate attention.</summary>
-    [JsonPropertyName("emergency")]
+    [JsonStringEnumMemberName("emergency")]
     Emergency
 }

src/ModelContextProtocol/Protocol/Types/Role.cs

@@ -11,12 +11,12 @@ public enum Role
     /// <summary>
     /// Corresponds to the user in the conversation.
     /// </summary>
-    [JsonPropertyName("user")]
+    [JsonStringEnumMemberName("user")]
     User,
 
     /// <summary>
     /// Corresponds to the AI in the conversation.
     /// </summary>
-    [JsonPropertyName("assistant")]
+    [JsonStringEnumMemberName("assistant")]
     Assistant
 }