Delete EnumSchema type and update references to use LegacyTitledEnumSchema

Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>

Author: Copilot

src/ModelContextProtocol.Core/Protocol/ElicitRequestParams.cs

@@ -315,11 +315,9 @@ public sealed class Converter : JsonConverter<PrimitiveSchemaDefinition>
                         {
                             if (enumNames is not null)
                             {
-                                // EnumSchema is deprecated but supported for backward compatibility.
-                                // Use the EnumSchema class, which is an alias for LegacyTitledEnumSchema,
-                                // to ensure backward compatibility with existing code relying on that type.
+                                // LegacyTitledEnumSchema is deprecated but supported for backward compatibility.
 #pragma warning disable MCP9001
-                                psd = new EnumSchema
+                                psd = new LegacyTitledEnumSchema
 #pragma warning restore MCP9001
                                 {
                                     Enum = enumValues,
@@ -647,25 +645,6 @@ public override void Write(Utf8JsonWriter writer, PrimitiveSchemaDefinition valu
                         }
                         break;
 
-#pragma warning disable MCP9001 // EnumSchema is deprecated but supported for backward compatibility
-                    case EnumSchema enumSchema:
-#pragma warning restore MCP9001
-                        if (enumSchema.Enum is not null)
-                        {
-                            writer.WritePropertyName("enum");
-                            JsonSerializer.Serialize(writer, enumSchema.Enum, McpJsonUtilities.JsonContext.Default.IListString);
-                        }
-                        if (enumSchema.EnumNames is not null)
-                        {
-                            writer.WritePropertyName("enumNames");
-                            JsonSerializer.Serialize(writer, enumSchema.EnumNames, McpJsonUtilities.JsonContext.Default.IListString);
-                        }
-                        if (enumSchema.Default is not null)
-                        {
-                            writer.WriteString("default", enumSchema.Default);
-                        }
-                        break;
-
                     default:
                         throw new JsonException($"Unexpected schema type: {value.GetType().Name}");
                 }
@@ -1013,52 +992,6 @@ public override string Type
         public IList<string>? Default { get; set; }
     }
 
-    /// <summary>
-    /// Represents a legacy schema for an enum type with enumNames.
-    /// This is a compatibility alias for <see cref="LegacyTitledEnumSchema"/>.
-    /// </summary>
-    /// <remarks>
-    /// This schema is deprecated in favor of <see cref="TitledSingleSelectEnumSchema"/>.
-    /// </remarks>
-    [Obsolete(Obsoletions.LegacyTitledEnumSchema_Message, DiagnosticId = Obsoletions.LegacyTitledEnumSchema_DiagnosticId, UrlFormat = Obsoletions.LegacyTitledEnumSchema_Url)]
-    public sealed class EnumSchema : PrimitiveSchemaDefinition
-    {
-        /// <inheritdoc/>
-        [JsonPropertyName("type")]
-        public override string Type
-        {
-            get => "string";
-            set
-            {
-                if (value is not "string")
-                {
-                    throw new ArgumentException("Type must be 'string'.", nameof(value));
-                }
-            }
-        }
-
-        /// <summary>Gets or sets the list of allowed string values for the enum.</summary>
-        [JsonPropertyName("enum")]
-        [field: MaybeNull]
-        public IList<string> Enum
-        {
-            get => field ??= [];
-            set
-            {
-                Throw.IfNull(value);
-                field = value;
-            }
-        }
-
-        /// <summary>Gets or sets optional display names corresponding to the enum values.</summary>
-        [JsonPropertyName("enumNames")]
-        public IList<string>? EnumNames { get; set; }
-
-        /// <summary>Gets or sets the default value for the enum.</summary>
-        [JsonPropertyName("default")]
-        public string? Default { get; set; }
-    }
-
     /// <summary>
     /// Represents a legacy schema for an enum type with enumNames.
     /// </summary>

tests/ModelContextProtocol.Tests/Protocol/EnumSchemaTests.cs

@@ -298,7 +298,7 @@ public void LegacyTitledEnumSchema_Serializes_Correctly()
 
         // Assert
         Assert.NotNull(deserialized);
-        var result = Assert.IsType<ElicitRequestParams.EnumSchema>(deserialized);
+        var result = Assert.IsType<ElicitRequestParams.LegacyTitledEnumSchema>(deserialized);
         Assert.Equal("string", result.Type);
         Assert.Equal("Environment", result.Title);
         Assert.Equal("Deployment environment", result.Description);
@@ -309,10 +309,10 @@ public void LegacyTitledEnumSchema_Serializes_Correctly()
     }
 
     [Fact]
-    public void EnumSchema_Serializes_Correctly()
+    public void LegacyTitledEnumSchema_Direct_Serializes_Correctly()
     {
         // Arrange
-        var schema = new ElicitRequestParams.EnumSchema
+        var schema = new ElicitRequestParams.LegacyTitledEnumSchema
         {
             Title = "Environment",
             Description = "Deployment environment",
@@ -327,7 +327,7 @@ public void EnumSchema_Serializes_Correctly()
 
         // Assert
         Assert.NotNull(deserialized);
-        var result = Assert.IsType<ElicitRequestParams.EnumSchema>(deserialized);
+        var result = Assert.IsType<ElicitRequestParams.LegacyTitledEnumSchema>(deserialized);
         Assert.Equal("string", result.Type);
         Assert.Equal("Environment", result.Title);
         Assert.Equal("Deployment environment", result.Description);
@@ -338,9 +338,9 @@ public void EnumSchema_Serializes_Correctly()
     }
 
     [Fact]
-    public void Enum_WithEnumNames_Deserializes_As_EnumSchema()
+    public void Enum_WithEnumNames_Deserializes_As_LegacyTitledEnumSchema()
     {
-        // Arrange - JSON with enumNames should deserialize as (deprecated) EnumSchema
+        // Arrange - JSON with enumNames should deserialize as (deprecated) LegacyTitledEnumSchema
         string json = """
             {
                 "type": "string",
@@ -356,7 +356,7 @@ public void Enum_WithEnumNames_Deserializes_As_EnumSchema()
 
         // Assert
         Assert.NotNull(deserialized);
-        var result = Assert.IsType<ElicitRequestParams.EnumSchema>(deserialized);
+        var result = Assert.IsType<ElicitRequestParams.LegacyTitledEnumSchema>(deserialized);
         Assert.Equal("string", result.Type);
         Assert.Equal("Environment", result.Title);
         Assert.Equal("Deployment environment", result.Description);

tests/ModelContextProtocol.Tests/Protocol/PrimitiveSchemaDefinitionTests.cs

@@ -283,7 +283,7 @@ public static void LegacyTitledEnumSchema_UnknownProperties_AreIgnored()
             json,
             McpJsonUtilities.DefaultOptions);
         Assert.NotNull(result);
-        var enumSchema = Assert.IsType<ElicitRequestParams.EnumSchema>(result);
+        var enumSchema = Assert.IsType<ElicitRequestParams.LegacyTitledEnumSchema>(result);
         Assert.Equal("string", enumSchema.Type);
         Assert.Equal(2, enumSchema.Enum.Count);
         Assert.Contains("option1", enumSchema.Enum);