Use dedicated type for resource collections.

Author: eiriktsarpalis

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/McpServerPrimitiveCollection.cs

@@ -15,11 +15,9 @@ public class McpServerPrimitiveCollection<T> : ICollection<T>, IReadOnlyCollecti
     /// <summary>
     /// Initializes a new instance of the <see cref="McpServerPrimitiveCollection{T}"/> class.
     /// </summary>
-    public McpServerPrimitiveCollection()
+    public McpServerPrimitiveCollection(IEqualityComparer<string>? keyComparer = null)
     {
-        _primitives = typeof(T) == typeof(McpServerResource)
-            ? new(UriTemplate.UriTemplateComparer.Instance)
-            : new();
+        _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/McpServerOptionsSetup.cs

@@ -63,7 +63,7 @@ public void Configure(McpServerOptions options)
         // 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/Server/McpServerResourceTests.cs

@@ -285,7 +285,7 @@ public async Task ResourceCollection_UsesCaseInsensitiveHostLookup()
     {
         McpServerResource t1 = McpServerResource.Create(() => "resource", new() { UriTemplate = "resource://MyCoolResource" });
         McpServerResource t2 = McpServerResource.Create(() => "resource", new() { UriTemplate = "resource://MyCoolResource2" });
-        McpServerPrimitiveCollection<McpServerResource> collection = new() { t1, t2 };
+        McpServerResourceCollection collection = new() { t1, t2 };
         Assert.True(collection.TryGetPrimitive("resource://mycoolresource", out McpServerResource? result));
         Assert.Same(t1, result);
     }