From 96267c2caf040bc4b4f4ac92604a29b6dbbe3397 Mon Sep 17 00:00:00 2001
From: goutamadwant <workwithgoutam@gmail.com>
Date: Sat, 27 Jun 2026 23:42:43 -0700
Subject: [PATCH] Apply default tool annotations from attributes

---
 .../Server/AIFunctionMcpServerTool.cs         | 25 ++++---------------
 .../Client/McpClientTests.cs                  |  6 ++---
 .../McpServerBuilderExtensionsToolsTests.cs   |  8 +++---
 3 files changed, 12 insertions(+), 27 deletions(-)

diff --git a/src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs b/src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs
index 82b6ceb9d..54d6f740a 100644
--- a/src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs
+++ b/src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs
@@ -167,25 +167,10 @@ private static McpServerToolCreateOptions DeriveOptions(MethodInfo method, McpSe
             newOptions.Name ??= toolAttr.Name;
             newOptions.Title ??= toolAttr.Title;
 
-            if (toolAttr._destructive is bool destructive)
-            {
-                newOptions.Destructive ??= destructive;
-            }
-
-            if (toolAttr._idempotent is bool idempotent)
-            {
-                newOptions.Idempotent ??= idempotent;
-            }
-
-            if (toolAttr._openWorld is bool openWorld)
-            {
-                newOptions.OpenWorld ??= openWorld;
-            }
-
-            if (toolAttr._readOnly is bool readOnly)
-            {
-                newOptions.ReadOnly ??= readOnly;
-            }
+            newOptions.Destructive ??= toolAttr.Destructive;
+            newOptions.Idempotent ??= toolAttr.Idempotent;
+            newOptions.OpenWorld ??= toolAttr.OpenWorld;
+            newOptions.ReadOnly ??= toolAttr.ReadOnly;
 
             if (newOptions.Icons is null && toolAttr.IconSource is { Length: > 0 } iconSource)
             {
@@ -805,4 +790,4 @@ private static bool IsPrimitiveHeaderType(Type type)
                type == typeof(uint) ||
                type == typeof(long);
     }
-}
\ No newline at end of file
+}
diff --git a/tests/ModelContextProtocol.Tests/Client/McpClientTests.cs b/tests/ModelContextProtocol.Tests/Client/McpClientTests.cs
index 4dda7bc38..9e9b9a5e7 100644
--- a/tests/ModelContextProtocol.Tests/Client/McpClientTests.cs
+++ b/tests/ModelContextProtocol.Tests/Client/McpClientTests.cs
@@ -367,15 +367,15 @@ public async Task ListToolsAsync_AllToolsReturned()
 
         var valuesSetViaAttr = tools.Single(t => t.Name == "ValuesSetViaAttr");
         Assert.Null(valuesSetViaAttr.ProtocolTool.Annotations?.Title);
-        Assert.Null(valuesSetViaAttr.ProtocolTool.Annotations?.ReadOnlyHint);
-        Assert.Null(valuesSetViaAttr.ProtocolTool.Annotations?.IdempotentHint);
+        Assert.False(valuesSetViaAttr.ProtocolTool.Annotations?.ReadOnlyHint);
+        Assert.False(valuesSetViaAttr.ProtocolTool.Annotations?.IdempotentHint);
         Assert.False(valuesSetViaAttr.ProtocolTool.Annotations?.DestructiveHint);
         Assert.True(valuesSetViaAttr.ProtocolTool.Annotations?.OpenWorldHint);
 
         var valuesSetViaOptions = tools.Single(t => t.Name == "ValuesSetViaOptions");
         Assert.Null(valuesSetViaOptions.ProtocolTool.Annotations?.Title);
         Assert.True(valuesSetViaOptions.ProtocolTool.Annotations?.ReadOnlyHint);
-        Assert.Null(valuesSetViaOptions.ProtocolTool.Annotations?.IdempotentHint);
+        Assert.False(valuesSetViaOptions.ProtocolTool.Annotations?.IdempotentHint);
         Assert.True(valuesSetViaOptions.ProtocolTool.Annotations?.DestructiveHint);
         Assert.False(valuesSetViaOptions.ProtocolTool.Annotations?.OpenWorldHint);
     }
diff --git a/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsToolsTests.cs b/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsToolsTests.cs
index 5359ec73c..dadc23c9f 100644
--- a/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsToolsTests.cs
+++ b/tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsToolsTests.cs
@@ -698,10 +698,10 @@ public void Create_ExtractsToolAnnotations_SomeSet()
         var annotations = tool.ProtocolTool.Annotations;
         Assert.NotNull(annotations);
         Assert.Null(annotations.Title);
-        Assert.Null(annotations.DestructiveHint);
+        Assert.True(annotations.DestructiveHint);
         Assert.False(annotations.IdempotentHint);
-        Assert.Null(annotations.OpenWorldHint);
-        Assert.Null(annotations.ReadOnlyHint);
+        Assert.True(annotations.OpenWorldHint);
+        Assert.False(annotations.ReadOnlyHint);
     }
 
     [Fact]
@@ -970,4 +970,4 @@ public class ComplexObject
     [JsonSerializable(typeof(JsonElement))]
     [JsonSerializable(typeof(CallToolResult))]
     partial class BuilderToolsJsonContext : JsonSerializerContext;
-}
\ No newline at end of file
+}