Add tests and sample usage for McpMetaAttribute

Co-authored-by: stephentoub <[email protected]>

Author: Copilot

samples/AspNetCoreMcpServer/Tools/WeatherTools.cs

@@ -17,6 +17,8 @@ public WeatherTools(IHttpClientFactory httpClientFactory)
     }
 
     [McpServerTool, Description("Get weather alerts for a US state.")]
+    [McpMeta(Name = "category", Value = "weather")]
+    [McpMeta(Name = "dataSource", Value = "weather.gov")]
     public async Task<string> GetAlerts(
         [Description("The US state to get alerts for. Use the 2 letter abbreviation for the state (e.g. NY).")] string state)
     {
@@ -46,6 +48,8 @@ public async Task<string> GetAlerts(
     }
 
     [McpServerTool, Description("Get weather forecast for a location.")]
+    [McpMeta(Name = "category", Value = "weather")]
+    [McpMeta(Name = "recommendedModel", Value = "gpt-4")]
     public async Task<string> GetForecast(
         [Description("Latitude of the location.")] double latitude,
         [Description("Longitude of the location.")] double longitude)

tests/ModelContextProtocol.Tests/Server/McpMetaAttributeTests.cs

@@ -0,0 +1,128 @@
+using ModelContextProtocol.Protocol;
+using ModelContextProtocol.Server;
+using System.Reflection;
+using System.Text.Json.Nodes;
+
+namespace ModelContextProtocol.Tests.Server;
+
+public class McpMetaAttributeTests
+{
+    [Fact]
+    public void McpMetaAttribute_OnTool_PopulatesMeta()
+    {
+        // Arrange
+        var method = typeof(TestToolClass).GetMethod(nameof(TestToolClass.ToolWithMeta))!;
+        
+        // Act
+        var tool = McpServerTool.Create(method, null);
+        
+        // Assert
+        Assert.NotNull(tool.ProtocolTool.Meta);
+        Assert.Equal("gpt-4o", tool.ProtocolTool.Meta["model"]?.ToString());
+        Assert.Equal("1.0", tool.ProtocolTool.Meta["version"]?.ToString());
+    }
+
+    [Fact]
+    public void McpMetaAttribute_OnPrompt_PopulatesMeta()
+    {
+        // Arrange
+        var method = typeof(TestPromptClass).GetMethod(nameof(TestPromptClass.PromptWithMeta))!;
+        
+        // Act
+        var prompt = McpServerPrompt.Create(method, null);
+        
+        // Assert
+        Assert.NotNull(prompt.ProtocolPrompt.Meta);
+        Assert.Equal("reasoning", prompt.ProtocolPrompt.Meta["type"]?.ToString());
+        Assert.Equal("claude-3", prompt.ProtocolPrompt.Meta["model"]?.ToString());
+    }
+
+    [Fact]
+    public void McpMetaAttribute_OnResource_PopulatesMeta()
+    {
+        // Arrange
+        var method = typeof(TestResourceClass).GetMethod(nameof(TestResourceClass.ResourceWithMeta))!;
+        
+        // Act
+        var resource = McpServerResource.Create(method, null);
+        
+        // Assert
+        Assert.NotNull(resource.ProtocolResource.Meta);
+        Assert.Equal("text/plain", resource.ProtocolResource.Meta["encoding"]?.ToString());
+        Assert.Equal("cached", resource.ProtocolResource.Meta["caching"]?.ToString());
+    }
+
+    [Fact]
+    public void McpMetaAttribute_WithoutAttributes_ReturnsNull()
+    {
+        // Arrange
+        var method = typeof(TestToolClass).GetMethod(nameof(TestToolClass.ToolWithoutMeta))!;
+        
+        // Act
+        var tool = McpServerTool.Create(method, null);
+        
+        // Assert
+        Assert.Null(tool.ProtocolTool.Meta);
+    }
+
+    [Fact]
+    public void McpMetaAttribute_SingleAttribute_PopulatesMeta()
+    {
+        // Arrange
+        var method = typeof(TestToolClass).GetMethod(nameof(TestToolClass.ToolWithSingleMeta))!;
+        
+        // Act
+        var tool = McpServerTool.Create(method, null);
+        
+        // Assert
+        Assert.NotNull(tool.ProtocolTool.Meta);
+        Assert.Equal("test-value", tool.ProtocolTool.Meta["test-key"]?.ToString());
+        Assert.Single(tool.ProtocolTool.Meta);
+    }
+
+    private class TestToolClass
+    {
+        [McpServerTool]
+        [McpMeta(Name = "model", Value = "gpt-4o")]
+        [McpMeta(Name = "version", Value = "1.0")]
+        public static string ToolWithMeta(string input)
+        {
+            return input;
+        }
+
+        [McpServerTool]
+        public static string ToolWithoutMeta(string input)
+        {
+            return input;
+        }
+
+        [McpServerTool]
+        [McpMeta(Name = "test-key", Value = "test-value")]
+        public static string ToolWithSingleMeta(string input)
+        {
+            return input;
+        }
+    }
+
+    private class TestPromptClass
+    {
+        [McpServerPrompt]
+        [McpMeta(Name = "type", Value = "reasoning")]
+        [McpMeta(Name = "model", Value = "claude-3")]
+        public static string PromptWithMeta(string input)
+        {
+            return input;
+        }
+    }
+
+    private class TestResourceClass
+    {
+        [McpServerResource(UriTemplate = "resource://test/{id}")]
+        [McpMeta(Name = "encoding", Value = "text/plain")]
+        [McpMeta(Name = "caching", Value = "cached")]
+        public static string ResourceWithMeta(string id)
+        {
+            return $"Resource content for {id}";
+        }
+    }
+}