Make Tool.Name required to match other protocol types (#1351)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: stephentoub <2642209+stephentoub@users.noreply.github.com>

Author: Copilot

src/ModelContextProtocol.Core/Protocol/Tool.cs

@@ -15,7 +15,7 @@ public sealed class Tool : IBaseMetadata
 {
     /// <inheritdoc />
     [JsonPropertyName("name")]
-    public string Name { get; set; } = string.Empty;
+    public required string Name { get; set; }
 
     /// <inheritdoc />
     [JsonPropertyName("title")]

tests/ModelContextProtocol.Tests/Protocol/ToolTests.cs

@@ -95,7 +95,7 @@ public static void Tool_HasCorrectJsonPropertyNames()
     [Fact]
     public static void ToolInputSchema_HasValidDefaultSchema()
     {
-        var tool = new Tool();
+        var tool = new Tool { Name = "test" };
         JsonElement jsonElement = tool.InputSchema;
 
         Assert.Equal(JsonValueKind.Object, jsonElement.ValueKind);
@@ -119,7 +119,7 @@ public static void ToolInputSchema_HasValidDefaultSchema()
     public static void ToolInputSchema_RejectsInvalidSchemaDocuments(string invalidSchema)
     {
         using var document = JsonDocument.Parse(invalidSchema);
-        var tool = new Tool();
+        var tool = new Tool { Name = "test" };
 
         Assert.Throws<ArgumentException>(() => tool.InputSchema = document.RootElement);
     }
@@ -133,6 +133,7 @@ public static void ToolInputSchema_AcceptsValidSchemaDocuments(string validSchem
         using var document = JsonDocument.Parse(validSchema);
         Tool tool = new()
         {
+            Name = "test",
             InputSchema = document.RootElement
         };