lower_snake_case all the things

Author: stephentoub

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerPrompt.cs

@@ -68,7 +68,7 @@ private static AIFunctionFactoryOptions CreateAIFunctionFactoryOptions(
         MethodInfo method, McpServerPromptCreateOptions? options) =>
         new()
         {
-            Name = options?.Name ?? method.GetCustomAttribute<McpServerPromptAttribute>()?.Name ?? AIFunctionMcpServerTool.DeriveName(method, JsonNamingPolicy.CamelCase),
+            Name = options?.Name ?? method.GetCustomAttribute<McpServerPromptAttribute>()?.Name ?? AIFunctionMcpServerTool.DeriveName(method),
             Description = options?.Description,
             MarshalResult = static (result, _, cancellationToken) => new ValueTask<object?>(result),
             SerializerOptions = options?.SerializerOptions ?? McpJsonUtilities.DefaultOptions,

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerResource.cs

@@ -75,7 +75,7 @@ private static AIFunctionFactoryOptions CreateAIFunctionFactoryOptions(
         MethodInfo method, McpServerResourceCreateOptions? options) =>
         new()
         {
-            Name = options?.Name ?? method.GetCustomAttribute<McpServerResourceAttribute>()?.Name,
+            Name = options?.Name ?? method.GetCustomAttribute<McpServerResourceAttribute>()?.Name ?? AIFunctionMcpServerTool.DeriveName(method),
             Description = options?.Description,
             MarshalResult = static (result, _, cancellationToken) => new ValueTask<object?>(result),
             SerializerOptions = options?.SerializerOptions ?? McpJsonUtilities.DefaultOptions,

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerTool.cs

@@ -75,7 +75,7 @@ private static AIFunctionFactoryOptions CreateAIFunctionFactoryOptions(
         MethodInfo method, McpServerToolCreateOptions? options) =>
         new()
         {
-            Name = options?.Name ?? method.GetCustomAttribute<McpServerToolAttribute>()?.Name ?? DeriveName(method, JsonNamingPolicy.SnakeCaseLower),
+            Name = options?.Name ?? method.GetCustomAttribute<McpServerToolAttribute>()?.Name ?? DeriveName(method),
             Description = options?.Description,
             MarshalResult = static (result, _, cancellationToken) => new ValueTask<object?>(result),
             SerializerOptions = options?.SerializerOptions ?? McpJsonUtilities.DefaultOptions,
@@ -295,7 +295,7 @@ public override async ValueTask<CallToolResult> InvokeAsync(
     }
 
     /// <summary>Creates a name to use based on the supplied method and naming policy.</summary>
-    internal static string DeriveName(MethodInfo method, JsonNamingPolicy? policy)
+    internal static string DeriveName(MethodInfo method, JsonNamingPolicy? policy = null)
     {
         string name = method.Name;
 
@@ -318,7 +318,7 @@ internal static string DeriveName(MethodInfo method, JsonNamingPolicy? policy)
         }
 
         // Case the name based on the provided naming policy.
-        return policy?.ConvertName(name) ?? name;
+        return (policy ?? JsonNamingPolicy.SnakeCaseLower).ConvertName(name) ?? name;
 
         static bool IsAsyncMethod(MethodInfo method)
         {

tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsPromptsTests.cs

@@ -100,7 +100,7 @@ public async Task Can_List_And_Call_Registered_Prompts()
         var prompts = await client.ListPromptsAsync(TestContext.Current.CancellationToken);
         Assert.Equal(6, prompts.Count);
 
-        var prompt = prompts.First(t => t.Name == "returnsChatMessages");
+        var prompt = prompts.First(t => t.Name == "returns_chat_messages");
         Assert.Equal("Returns chat messages", prompt.Description);
 
         var result = await prompt.GetAsync(new Dictionary<string, object?>() { ["message"] = "hello" }, cancellationToken: TestContext.Current.CancellationToken);
@@ -171,7 +171,7 @@ public async Task TitleAttributeProperty_PropagatedToTitle()
         Assert.NotNull(prompts);
         Assert.NotEmpty(prompts);
 
-        McpClientPrompt prompt = prompts.First(t => t.Name == "returnsString");
+        McpClientPrompt prompt = prompts.First(t => t.Name == "returns_string");
 
         Assert.Equal("This is a title", prompt.Title);
     }
@@ -204,7 +204,7 @@ public async Task Throws_Exception_Missing_Parameter()
         await using IMcpClient client = await CreateMcpClientForServer();
 
         var e = await Assert.ThrowsAsync<McpException>(async () => await client.GetPromptAsync(
-            "returnsChatMessages",
+            "returns_chat_messages",
             cancellationToken: TestContext.Current.CancellationToken));
 
         Assert.Equal(McpErrorCode.InternalError, e.ErrorCode);
@@ -242,7 +242,7 @@ public void Register_Prompts_From_Current_Assembly()
         sc.AddMcpServer().WithPromptsFromAssembly();
         IServiceProvider services = sc.BuildServiceProvider();
 
-        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "returnsChatMessages");
+        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "returns_chat_messages");
     }
 
     [Fact]
@@ -255,10 +255,10 @@ public void Register_Prompts_From_Multiple_Sources()
             .WithPrompts([McpServerPrompt.Create(() => "42", new() { Name = "Returns42" })]);
         IServiceProvider services = sc.BuildServiceProvider();
 
-        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "returnsChatMessages");
-        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "throwsException");
-        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "returnsString");
-        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "anotherPrompt");
+        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "returns_chat_messages");
+        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "throws_exception");
+        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "returns_string");
+        Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "another_prompt");
         Assert.Contains(services.GetServices<McpServerPrompt>(), t => t.ProtocolPrompt.Name == "Returns42");
     }
 

tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsResourcesTests.cs

@@ -129,7 +129,7 @@ public async Task Can_List_And_Call_Registered_Resources()
         var resources = await client.ListResourcesAsync(TestContext.Current.CancellationToken);
         Assert.Equal(5, resources.Count);
 
-        var resource = resources.First(t => t.Name == nameof(SimpleResources.SomeNeatDirectResource));
+        var resource = resources.First(t => t.Name == "some_neat_direct_resource");
         Assert.Equal("Some neat direct resource", resource.Description);
 
         var result = await resource.ReadAsync(cancellationToken: TestContext.Current.CancellationToken);
@@ -146,7 +146,7 @@ public async Task Can_List_And_Call_Registered_ResourceTemplates()
         var resources = await client.ListResourceTemplatesAsync(TestContext.Current.CancellationToken);
         Assert.Equal(3, resources.Count);
 
-        var resource = resources.First(t => t.Name == nameof(SimpleResources.SomeNeatTemplatedResource));
+        var resource = resources.First(t => t.Name == "some_neat_templated_resource");
         Assert.Equal("Some neat resource with parameters", resource.Description);
 
         var result = await resource.ReadAsync(new Dictionary<string, object?>() { ["name"] = "hello" }, cancellationToken: TestContext.Current.CancellationToken);
@@ -204,13 +204,13 @@ public async Task TitleAttributeProperty_PropagatedToTitle()
         var resources = await client.ListResourcesAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.NotNull(resources);
         Assert.NotEmpty(resources);
-        McpClientResource resource = resources.First(t => t.Name == nameof(SimpleResources.SomeNeatDirectResource));
+        McpClientResource resource = resources.First(t => t.Name == "some_neat_direct_resource");
         Assert.Equal("This is a title", resource.Title);
 
         var resourceTemplates = await client.ListResourceTemplatesAsync(cancellationToken: TestContext.Current.CancellationToken);
         Assert.NotNull(resourceTemplates);
         Assert.NotEmpty(resourceTemplates);
-        McpClientResourceTemplate resourceTemplate = resourceTemplates.First(t => t.Name == nameof(SimpleResources.SomeNeatTemplatedResource));
+        McpClientResourceTemplate resourceTemplate = resourceTemplates.First(t => t.Name == "some_neat_templated_resource");
         Assert.Equal("This is another title", resourceTemplate.Title);
     }
 
@@ -268,8 +268,8 @@ public void Register_Resources_From_Current_Assembly()
         sc.AddMcpServer().WithResourcesFromAssembly();
         IServiceProvider services = sc.BuildServiceProvider();
 
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://mcp/{nameof(SimpleResources.SomeNeatDirectResource)}");
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/{nameof(SimpleResources.SomeNeatTemplatedResource)}{{?name}}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://mcp/some_neat_direct_resource");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/some_neat_templated_resource{{?name}}");
     }
 
     [Fact]
@@ -282,9 +282,9 @@ public void Register_Resources_From_Multiple_Sources()
             .WithResources([McpServerResource.Create(() => "42", new() { UriTemplate = "myResources:///returns42/{something}" })]);
         IServiceProvider services = sc.BuildServiceProvider();
 
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://mcp/{nameof(SimpleResources.SomeNeatDirectResource)}");
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/{nameof(SimpleResources.SomeNeatTemplatedResource)}{{?name}}");
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/{nameof(MoreResources.AnotherNeatDirectResource)}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://mcp/some_neat_direct_resource");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/some_neat_templated_resource{{?name}}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/another_neat_direct_resource");
         Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate.UriTemplate == "myResources:///returns42/{something}");
     }