Fix URI template derivation and lookup (#530)

* Use lowercase host in resource URI template derivation.

* Address feedback

* Add casing testing for non-templated resource lookups.

* Fix uri primitive lookup

* Use a hardcoded mcp hostname in derived resource template URIs and ensure built-in resources work with the VS Code client.

* Address feedback

* Fix equality comparison

* Use dedicated type for resource collections.

samples/AspNetCoreSseServer/Program.cs

@@ -2,12 +2,14 @@ using OpenTelemetry;
 using OpenTelemetry.Metrics;
 using OpenTelemetry.Trace;
 using TestServerWithHosting.Tools;
+using TestServerWithHosting.Resources;
 
 var builder = WebApplication.CreateBuilder(args);
 builder.Services.AddMcpServer()
     .WithHttpTransport()
     .WithTools<EchoTool>()
-    .WithTools<SampleLlmTool>();
+    .WithTools<SampleLlmTool>()
+    .WithResources<SimpleResourceType>();
 
 builder.Services.AddOpenTelemetry()
     .WithTracing(b => b.AddSource("*")

samples/AspNetCoreSseServer/Resources/SimpleResourceType.cs

@@ -0,0 +1,12 @@
+using ModelContextProtocol.Protocol;
+using ModelContextProtocol.Server;
+using System.ComponentModel;
+
+namespace TestServerWithHosting.Resources;
+
+[McpServerResourceType]
+public class SimpleResourceType
+{
+    [McpServerResource, Description("A direct text resource")]
+    public static string DirectTextResource() => "This is a direct resource";
+}

src/ModelContextProtocol.Core/Protocol/ResourcesCapability.cs

@@ -103,5 +103,5 @@ public sealed class ResourcesCapability
     /// </para>
     /// </remarks>
     [JsonIgnore]
-    public McpServerPrimitiveCollection<McpServerResource>? ResourceCollection { get; set; }
+    public McpServerResourceCollection? ResourceCollection { get; set; }
 }

src/ModelContextProtocol.Core/Server/AIFunctionMcpServerResource.cs

@@ -264,7 +264,7 @@ internal sealed class AIFunctionMcpServerResource : McpServerResource
             Name = name,
             Title = options?.Title,
             Description = options?.Description,
-            MimeType = options?.MimeType,
+            MimeType = options?.MimeType ?? "application/octet-stream",
         };
 
         return new AIFunctionMcpServerResource(function, resource);
@@ -295,7 +295,7 @@ internal sealed class AIFunctionMcpServerResource : McpServerResource
     {
         StringBuilder template = new();
 
-        template.Append("resource://").Append(Uri.EscapeDataString(name));
+        template.Append("resource://mcp/").Append(Uri.EscapeDataString(name));
 
         if (function.JsonSchema.TryGetProperty("properties", out JsonElement properties))
         {
@@ -359,7 +359,7 @@ internal sealed class AIFunctionMcpServerResource : McpServerResource
                 return null;
             }
         }
-        else if (request.Params.Uri != ProtocolResource!.Uri)
+        else if (!UriTemplate.UriTemplateComparer.Instance.Equals(request.Params.Uri, ProtocolResource!.Uri))
         {
             return null;
         }

src/ModelContextProtocol.Core/Server/McpServer.cs

@@ -228,7 +228,7 @@ internal sealed class McpServer : McpEndpoint, IMcpServer
         var unsubscribeHandler = resourcesCapability.UnsubscribeFromResourcesHandler ?? (static async (_, __) => new EmptyResult());
         var resources = resourcesCapability.ResourceCollection;
         var listChanged = resourcesCapability.ListChanged;
-        var subcribe = resourcesCapability.Subscribe;
+        var subscribe = resourcesCapability.Subscribe;
 
         // Handle resources provided via DI.
         if (resources is { IsEmpty: false })
@@ -309,7 +309,7 @@ internal sealed class McpServer : McpEndpoint, IMcpServer
             listChanged = true;
 
             // TODO: Implement subscribe/unsubscribe logic for resource and resource template collections.
-            // subcribe = true;
+            // subscribe = true;
         }
 
         ServerCapabilities.Resources.ListResourcesHandler = listResourcesHandler;
@@ -319,7 +319,7 @@ internal sealed class McpServer : McpEndpoint, IMcpServer
         ServerCapabilities.Resources.SubscribeToResourcesHandler = subscribeHandler;
         ServerCapabilities.Resources.UnsubscribeFromResourcesHandler = unsubscribeHandler;
         ServerCapabilities.Resources.ListChanged = listChanged;
-        ServerCapabilities.Resources.Subscribe = subcribe;
+        ServerCapabilities.Resources.Subscribe = subscribe;
 
         SetHandler(
             RequestMethods.ResourcesList,

src/ModelContextProtocol.Core/Server/McpServerPrimitiveCollection.cs

@@ -10,13 +10,14 @@ public class McpServerPrimitiveCollection<T> : ICollection<T>, IReadOnlyCollecti
     where T : IMcpServerPrimitive
 {
     /// <summary>Concurrent dictionary of primitives, indexed by their names.</summary>
-    private readonly ConcurrentDictionary<string, T> _primitives = [];
+    private readonly ConcurrentDictionary<string, T> _primitives;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="McpServerPrimitiveCollection{T}"/> class.
     /// </summary>
-    public McpServerPrimitiveCollection()
+    public McpServerPrimitiveCollection(IEqualityComparer<string>? keyComparer = null)
     {
+        _primitives = new(keyComparer);
     }
 
     /// <summary>Occurs when the collection is changed.</summary>

src/ModelContextProtocol.Core/Server/McpServerResourceCollection.cs

@@ -0,0 +1,5 @@
+namespace ModelContextProtocol.Server;
+
+/// <summary>Provides a thread-safe collection of <see cref="McpServerResource"/> instances, indexed by their URI templates.</summary>
+public sealed class McpServerResourceCollection()
+    : McpServerPrimitiveCollection<McpServerResource>(UriTemplate.UriTemplateComparer.Instance);

src/ModelContextProtocol.Core/UriTemplate.cs

@@ -2,6 +2,7 @@
 using System.Buffers;
 #endif
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.Runtime.CompilerServices;
 using System.Text;
@@ -453,4 +454,53 @@ internal static partial class UriTemplate
             }
         }
     }
+
+    /// <summary>
+    /// Defines an equality comparer for Uri templates as follows:
+    /// 1. Non-templated Uris use regular System.Uri equality comparison (host name is case insensitive).
+    /// 2. Templated Uris use regular string equality.
+    /// 
+    /// We do this because non-templated resources are looked up directly from the resource dictionary
+    /// and we need to make sure equality is implemented correctly. Templated Uris are resolved in a
+    /// fallback step using linear traversal of the resource dictionary, so their equality is only
+    /// there to distinguish between different templates.
+    /// </summary>
+    public sealed class UriTemplateComparer : IEqualityComparer<string>
+    {
+        public static IEqualityComparer<string> Instance { get; } = new UriTemplateComparer();
+
+        public bool Equals(string? uriTemplate1, string? uriTemplate2)
+        {
+            if (TryParseAsNonTemplatedUri(uriTemplate1, out Uri? uri1) &&
+                TryParseAsNonTemplatedUri(uriTemplate2, out Uri? uri2))
+            {
+                return uri1 == uri2;
+            }
+
+            return string.Equals(uriTemplate1, uriTemplate2, StringComparison.Ordinal);
+        }
+
+        public int GetHashCode([DisallowNull] string uriTemplate)
+        {
+            if (TryParseAsNonTemplatedUri(uriTemplate, out Uri? uri))
+            {
+                return uri.GetHashCode();
+            }
+            else
+            {
+                return StringComparer.Ordinal.GetHashCode(uriTemplate);
+            }
+        }
+
+        private static bool TryParseAsNonTemplatedUri(string? uriTemplate, [NotNullWhen(true)] out Uri? uri)
+        {
+            if (uriTemplate is null || uriTemplate.Contains('{'))
+            {
+                uri = null;
+                return false;
+            }
+
+            return Uri.TryCreate(uriTemplate, UriKind.Absolute, out uri);
+        }
+    }
 }

src/ModelContextProtocol/McpServerOptionsSetup.cs

@@ -63,7 +63,7 @@ internal sealed class McpServerOptionsSetup(
         // a collection, add to it, otherwise create a new one. We want to maintain the identity
         // of an existing collection in case someone has provided their own derived type, wants
         // change notifications, etc.
-        McpServerPrimitiveCollection<McpServerResource> resourceCollection = options.Capabilities?.Resources?.ResourceCollection ?? [];
+        McpServerResourceCollection resourceCollection = options.Capabilities?.Resources?.ResourceCollection ?? [];
         foreach (var resource in serverResources)
         {
             resourceCollection.TryAdd(resource);

tests/ModelContextProtocol.Tests/Configuration/McpServerBuilderExtensionsResourcesTests.cs

@@ -220,7 +220,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
         await using IMcpClient client = await CreateMcpClientForServer();
 
         await Assert.ThrowsAsync<McpException>(async () => await client.ReadResourceAsync(
-            $"resource://{nameof(SimpleResources.ThrowsException)}",
+            $"resource://mcp/{nameof(SimpleResources.ThrowsException)}",
             cancellationToken: TestContext.Current.CancellationToken));
     }
 
@@ -230,7 +230,7 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
         await using IMcpClient client = await CreateMcpClientForServer();
 
         var e = await Assert.ThrowsAsync<McpException>(async () => await client.ReadResourceAsync(
-            "test://NotRegisteredResource",
+            "test:///NotRegisteredResource",
             cancellationToken: TestContext.Current.CancellationToken));
 
         Assert.Contains("Resource not found", e.Message);
@@ -268,8 +268,8 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
         sc.AddMcpServer().WithResourcesFromAssembly();
         IServiceProvider services = sc.BuildServiceProvider();
 
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://{nameof(SimpleResources.SomeNeatDirectResource)}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://mcp/{nameof(SimpleResources.SomeNeatDirectResource)}");
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://{nameof(SimpleResources.SomeNeatTemplatedResource)}{{?name}}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/{nameof(SimpleResources.SomeNeatTemplatedResource)}{{?name}}");
     }
 
     [Fact]
@@ -279,13 +279,13 @@ public partial class McpServerBuilderExtensionsResourcesTests : ClientServerTest
         sc.AddMcpServer()
             .WithResources<SimpleResources>()
             .WithResources<MoreResources>()
-            .WithResources([McpServerResource.Create(() => "42", new() { UriTemplate = "myResources://Returns42/{something}" })]);
+            .WithResources([McpServerResource.Create(() => "42", new() { UriTemplate = "myResources:///returns42/{something}" })]);
         IServiceProvider services = sc.BuildServiceProvider();
 
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://{nameof(SimpleResources.SomeNeatDirectResource)}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResource?.Uri == $"resource://mcp/{nameof(SimpleResources.SomeNeatDirectResource)}");
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://{nameof(SimpleResources.SomeNeatTemplatedResource)}{{?name}}");
+        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://{nameof(MoreResources.AnotherNeatDirectResource)}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate?.UriTemplate == $"resource://mcp/{nameof(MoreResources.AnotherNeatDirectResource)}");
-        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate.UriTemplate == "myResources://Returns42/{something}");
+        Assert.Contains(services.GetServices<McpServerResource>(), t => t.ProtocolResourceTemplate.UriTemplate == "myResources:///returns42/{something}");
     }
 
     [McpServerResourceType]

tests/ModelContextProtocol.Tests/Server/McpServerResourceTests.cs

@@ -122,159 +122,188 @@ public partial class McpServerResourceTests
     public async Task UriTemplate_CreatedFromParameters_LotsOfTypesSupported()
     {
         const string Name = "Hello";
+
         McpServerResource t;
         ReadResourceResult? result;
         IMcpServer server = new Mock<IMcpServer>().Object;
 
         t = McpServerResource.Create(() => "42", new() { Name = Name });
-        Assert.Equal($"resource://{Name}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal("resource://mcp/Hello", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}" } }, 
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = "resource://mcp/Hello" } }, 
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("42", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((IMcpServer server) => "42", new() { Name = Name });
-        Assert.Equal($"resource://{Name}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal("resource://mcp/Hello", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = "resource://mcp/Hello" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("42", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((string arg1) => arg1, new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?arg1}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?arg1}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?arg1=wOrLd" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?arg1=wOrLd" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("wOrLd", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((string arg1, string? arg2 = null) => arg1 + arg2, new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?arg1,arg2}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?arg1,arg2}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?arg1=wo&arg2=rld" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?arg1=wo&arg2=rld" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("world", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((object a1, bool a2, char a3, byte a4, sbyte a5) => a1.ToString() + a2 + a3 + a4 + a5, new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=hi&a2=true&a3=s&a4=12&a5=34" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=hi&a2=true&a3=s&a4=12&a5=34" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("hiTrues1234", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((ushort a1, short a2, uint a3, int a4, ulong a5) => (a1 + a2 + a3 + a4 + (long)a5).ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=10&a2=20&a3=30&a4=40&a5=50" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=10&a2=20&a3=30&a4=40&a5=50" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("150", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((long a1, float a2, double a3, decimal a4, TimeSpan a5) => a5.ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=1&a2=2&a3=3&a4=4&a5=5" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=1&a2=2&a3=3&a4=4&a5=5" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("5.00:00:00", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((DateTime a1, DateTimeOffset a2, Uri a3, Guid a4, Version a5) => a4.ToString("N") + a5, new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1={DateTime.UtcNow:r}&a2={DateTimeOffset.UtcNow:r}&a3=http%3A%2F%2Ftest&a4=14e5f43d-0d41-47d6-8207-8249cf669e41&a5=1.2.3.4" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1={DateTime.UtcNow:r}&a2={DateTimeOffset.UtcNow:r}&a3=http%3A%2F%2Ftest&a4=14e5f43d-0d41-47d6-8207-8249cf669e41&a5=1.2.3.4" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("14e5f43d0d4147d682078249cf669e411.2.3.4", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((Half a2, Int128 a3, UInt128 a4, IntPtr a5) => (a3 + (Int128)a4 + a5).ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a2=1.0&a3=3&a4=4&a5=5" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a2=1.0&a3=3&a4=4&a5=5" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("12", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((UIntPtr a1, DateOnly a2, TimeOnly a3) => a1.ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=123&a2=0001-02-03&a3=01%3A02%3A03" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=123&a2=0001-02-03&a3=01%3A02%3A03" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("123", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((bool? a2, char? a3, byte? a4, sbyte? a5) => a2?.ToString() + a3 + a4 + a5, new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a2=true&a3=s&a4=12&a5=34" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a2=true&a3=s&a4=12&a5=34" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("Trues1234", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((ushort? a1, short? a2, uint? a3, int? a4, ulong? a5) => (a1 + a2 + a3 + a4 + (long?)a5).ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=10&a2=20&a3=30&a4=40&a5=50" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=10&a2=20&a3=30&a4=40&a5=50" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("150", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((long? a1, float? a2, double? a3, decimal? a4, TimeSpan? a5) => a5?.ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=1&a2=2&a3=3&a4=4&a5=5" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=1&a2=2&a3=3&a4=4&a5=5" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("5.00:00:00", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((DateTime? a1, DateTimeOffset? a2, Guid? a4) => a4?.ToString("N"), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a4}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a4}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1={DateTime.UtcNow:r}&a2={DateTimeOffset.UtcNow:r}&a4=14e5f43d-0d41-47d6-8207-8249cf669e41" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1={DateTime.UtcNow:r}&a2={DateTimeOffset.UtcNow:r}&a4=14e5f43d-0d41-47d6-8207-8249cf669e41" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("14e5f43d0d4147d682078249cf669e41", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((Half? a2, Int128? a3, UInt128? a4, IntPtr? a5) => (a3 + (Int128?)a4 + a5).ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a2,a3,a4,a5}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a2=1.0&a3=3&a4=4&a5=5" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a2=1.0&a3=3&a4=4&a5=5" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("12", ((TextResourceContents)result.Contents[0]).Text);
 
         t = McpServerResource.Create((UIntPtr? a1, DateOnly? a2, TimeOnly? a3) => a1?.ToString(), new() { Name = Name });
-        Assert.Equal($"resource://{Name}{{?a1,a2,a3}}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal($"resource://mcp/Hello{{?a1,a2,a3}}", t.ProtocolResourceTemplate.UriTemplate);
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://{Name}?a1=123&a2=0001-02-03&a3=01%3A02%3A03" } },
+            new RequestContext<ReadResourceRequestParams>(server) { Params = new() { Uri = $"resource://mcp/Hello?a1=123&a2=0001-02-03&a3=01%3A02%3A03" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("123", ((TextResourceContents)result.Contents[0]).Text);
     }
 
     [Theory]
-    [InlineData("resource://Hello?arg1=42&arg2=84")]
+    [InlineData("resource://mcp/Hello?arg1=42&arg2=84")]
-    [InlineData("resource://Hello?arg1=42&arg2=84&arg3=123")]
+    [InlineData("resource://mcp/Hello?arg1=42&arg2=84&arg3=123")]
-    [InlineData("resource://Hello#fragment")]
+    [InlineData("resource://mcp/Hello#fragment")]
     public async Task UriTemplate_NonMatchingUri_ReturnsNull(string uri)
     {
         McpServerResource t = McpServerResource.Create((string arg1) => arg1, new() { Name = "Hello" });
-        Assert.Equal("resource://Hello{?arg1}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal("resource://mcp/Hello{?arg1}", t.ProtocolResourceTemplate.UriTemplate);
         Assert.Null(await t.ReadAsync(
             new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = uri } },
             TestContext.Current.CancellationToken));
     }
 
     [Theory]
-    [InlineData("resource://Hello?arg1=test")]
+    [InlineData("resource://MyCoolResource", "resource://mycoolresource")]
-    [InlineData("resource://Hello?arg2=test")]
+    [InlineData("resource://MyCoolResource{?arg1}", "resource://mycoolresource?arg1=42")]
+    public async Task UriTemplate_IsHostCaseInsensitive(string actualUri, string queriedUri)
+    {
+        McpServerResource t = McpServerResource.Create(() => "resource", new() { UriTemplate = actualUri });
+        Assert.NotNull(await t.ReadAsync(
+            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = queriedUri } },
+            TestContext.Current.CancellationToken));
+    }
+
+    [Fact]
+    public async Task ResourceCollection_UsesCaseInsensitiveHostLookup()
+    {
+        McpServerResource t1 = McpServerResource.Create(() => "resource", new() { UriTemplate = "resource://MyCoolResource" });
+        McpServerResource t2 = McpServerResource.Create(() => "resource", new() { UriTemplate = "resource://MyCoolResource2" });
+        McpServerResourceCollection collection = new() { t1, t2 };
+        Assert.True(collection.TryGetPrimitive("resource://mycoolresource", out McpServerResource? result));
+        Assert.Same(t1, result);
+    }
+
+    [Fact]
+    public void MimeType_DefaultsToOctetStream()
+    {
+        McpServerResource t = McpServerResource.Create(() => "resource", new() { Name = "My Cool Resource" });
+        Assert.Equal("application/octet-stream", t.ProtocolResourceTemplate.MimeType);
+    }
+
+    [Theory]
+    [InlineData("resource://mcp/Hello?arg1=test")]
+    [InlineData("resource://mcp/Hello?arg2=test")]
     public async Task UriTemplate_MissingParameter_Throws(string uri)
     {
         McpServerResource t = McpServerResource.Create((string arg1, int arg2) => arg1, new() { Name = "Hello" });
-        Assert.Equal("resource://Hello{?arg1,arg2}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal("resource://mcp/Hello{?arg1,arg2}", t.ProtocolResourceTemplate.UriTemplate);
         await Assert.ThrowsAsync<ArgumentException>(async () => await t.ReadAsync(
             new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = uri } },
             TestContext.Current.CancellationToken));
@@ -284,30 +313,30 @@ public partial class McpServerResourceTests
     public async Task UriTemplate_MissingOptionalParameter_Succeeds()
     {
         McpServerResource t = McpServerResource.Create((string? arg1 = null, int? arg2 = null) => arg1 + arg2, new() { Name = "Hello" });
-        Assert.Equal("resource://Hello{?arg1,arg2}", t.ProtocolResourceTemplate.UriTemplate);
+        Assert.Equal("resource://mcp/Hello{?arg1,arg2}", t.ProtocolResourceTemplate.UriTemplate);
 
         ReadResourceResult? result;
 
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://Hello" } },
+            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://mcp/Hello" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("", ((TextResourceContents)result.Contents[0]).Text);
 
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://Hello?arg1=first" } },
+            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://mcp/Hello?arg1=first" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("first", ((TextResourceContents)result.Contents[0]).Text);
 
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://Hello?arg2=42" } },
+            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://mcp/Hello?arg2=42" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("42", ((TextResourceContents)result.Contents[0]).Text);
 
         result = await t.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://Hello?arg1=first&arg2=42" } },
+            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://mcp/Hello?arg1=first&arg2=42" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("first42", ((TextResourceContents)result.Contents[0]).Text);
@@ -325,7 +354,7 @@ public partial class McpServerResourceTests
         }, new() { Name = "Test" });
 
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("42", ((TextResourceContents)result.Contents[0]).Text);
@@ -376,11 +405,11 @@ public partial class McpServerResourceTests
         Mock<IMcpServer> mockServer = new();
 
         await Assert.ThrowsAnyAsync<ArgumentException>(async () => await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken));
 
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Services = services, Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Services = services, Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("42", ((TextResourceContents)result.Contents[0]).Text);
@@ -402,7 +431,7 @@ public partial class McpServerResourceTests
         }, new() { Services = services, Name = "Test" });
 
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(new Mock<IMcpServer>().Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal("42", ((TextResourceContents)result.Contents[0]).Text);
@@ -436,7 +465,7 @@ public partial class McpServerResourceTests
             return new ReadResourceResult { Contents = new List<ResourceContents> { new TextResourceContents { Text = "hello" } } };
         }, new() { Name = "Test" });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Single(result.Contents);
@@ -453,7 +482,7 @@ public partial class McpServerResourceTests
             return new TextResourceContents { Text = "hello" };
         }, new() { Name = "Test", SerializerOptions = JsonContext6.Default.Options });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Single(result.Contents);
@@ -474,7 +503,7 @@ public partial class McpServerResourceTests
             ];
         }, new() { Name = "Test" });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal(2, result.Contents.Count);
@@ -492,7 +521,7 @@ public partial class McpServerResourceTests
             return "42";
         }, new() { Name = "Test" });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Single(result.Contents);
@@ -509,7 +538,7 @@ public partial class McpServerResourceTests
             return new List<string> { "42", "43" };
         }, new() { Name = "Test", SerializerOptions = JsonContext6.Default.Options });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal(2, result.Contents.Count);
@@ -527,7 +556,7 @@ public partial class McpServerResourceTests
             return new DataContent(new byte[] { 0, 1, 2 }, "application/octet-stream");
         }, new() { Name = "Test" });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Single(result.Contents);
@@ -549,7 +578,7 @@ public partial class McpServerResourceTests
             };
         }, new() { Name = "Test", SerializerOptions = JsonContext6.Default.Options });
         var result = await resource.ReadAsync(
-            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://Test" } },
+            new RequestContext<ReadResourceRequestParams>(mockServer.Object) { Params = new() { Uri = "resource://mcp/Test" } },
             TestContext.Current.CancellationToken);
         Assert.NotNull(result);
         Assert.Equal(2, result.Contents.Count);