fix: Add resource lookup by URI to support MCP client requests

Added support for finding resources by URI in addition to resource name. This fixes compatibility with Claude Code MCP client, which sends requests using the URI ('unity://hierarchy') instead of the resource name ('get_hierarchy').

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: dsarno

Diff for: Editor/UnityBridge/McpUnityServer.cs

@@ -66,6 +66,11 @@ public static McpUnityServer Instance
         /// </summary>
         public Dictionary<string, string> Clients => _clients;
 
+        /// <summary>
+        /// Dictionary of registered resources
+        /// </summary>
+        public Dictionary<string, McpResourceBase> Resources => _resources;
+        
         /// <summary>
         /// Private constructor to enforce singleton pattern
         /// </summary>

Diff for: Editor/UnityBridge/McpUnitySocketHandler.cs

@@ -77,7 +77,16 @@ protected override async void OnMessage(MessageEventArgs e)
                 }
                 else
                 {
-                    tcs.SetResult(CreateErrorResponse($"Unknown method: {method}", "unknown_method"));
+                    // Check if we're trying to access a resource by URI
+                    var resourceByUri = FindResourceByUri(method);
+                    if (resourceByUri != null)
+                    {
+                        EditorCoroutineUtility.StartCoroutineOwnerless(FetchResourceCoroutine(resourceByUri, parameters, tcs));
+                    }
+                    else
+                    {
+                        tcs.SetResult(CreateErrorResponse($"Unknown method: {method}", "unknown_method"));
+                    }
                 }
 
                 // Wait for the task to complete
@@ -191,6 +200,29 @@ private IEnumerator FetchResourceCoroutine(McpResourceBase resource, JObject par
             yield return null;
         }
 
+        /// <summary>
+        /// Find a resource by its URI
+        /// </summary>
+        /// <param name="uri">The URI to search for</param>
+        /// <returns>The resource if found, null otherwise</returns>
+        private McpResourceBase FindResourceByUri(string uri)
+        {
+            // Get resources from the server
+            var resources = _server.Resources;
+            
+            // Look for a resource with a matching URI
+            foreach (var resource in resources.Values)
+            {
+                if (resource.Uri == uri)
+                {
+                    Debug.Log($"[MCP Unity] Found resource {resource.Name} by URI {uri}");
+                    return resource;
+                }
+            }
+            
+            return null;
+        }
+        
         /// <summary>
         /// Create a JSON-RPC 2.0 response
         /// </summary>