Fix Claude uvx path resolution

Author: dsarno

MCPForUnity/Editor/Clients/Configurators/ClaudeDesktopConfigurator.cs

@@ -15,7 +15,8 @@ public ClaudeDesktopConfigurator() : base(new McpClient
             windowsConfigPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "Claude", "claude_desktop_config.json"),
             macConfigPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Library", "Application Support", "Claude", "claude_desktop_config.json"),
             linuxConfigPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".config", "Claude", "claude_desktop_config.json"),
-            SupportsHttpTransport = false
+            SupportsHttpTransport = false,
+            StripEnvWhenNotRequired = true
         })
         { }
 

MCPForUnity/Editor/Services/PathResolverService.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
@@ -34,6 +35,12 @@ public string GetUvxPath()
                 McpLog.Debug("No uvx path override found, falling back to default command");
             }
 
+            string discovered = ResolveUvxFromSystem();
+            if (!string.IsNullOrEmpty(discovered))
+            {
+                return discovered;
+            }
+
             return "uvx";
         }
 
@@ -123,6 +130,81 @@ public bool IsClaudeCliDetected()
             return !string.IsNullOrEmpty(GetClaudeCliPath());
         }
 
+        private static string ResolveUvxFromSystem()
+        {
+            try
+            {
+                foreach (string candidate in EnumerateUvxCandidates())
+                {
+                    if (!string.IsNullOrEmpty(candidate) && File.Exists(candidate))
+                    {
+                        return candidate;
+                    }
+                }
+            }
+            catch
+            {
+                // fall back to bare command
+            }
+
+            return null;
+        }
+
+        private static IEnumerable<string> EnumerateUvxCandidates()
+        {
+            string exeName = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? "uvx.exe" : "uvx";
+
+            string home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+            if (!string.IsNullOrEmpty(home))
+            {
+                yield return Path.Combine(home, ".local", "bin", exeName);
+                yield return Path.Combine(home, ".cargo", "bin", exeName);
+            }
+
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX))
+            {
+                yield return "/opt/homebrew/bin/" + exeName;
+                yield return "/usr/local/bin/" + exeName;
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+            {
+                yield return "/usr/local/bin/" + exeName;
+                yield return "/usr/bin/" + exeName;
+            }
+            else if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                string localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+                string programFiles = Environment.GetFolderPath(Environment.SpecialFolder.ProgramFiles);
+
+                if (!string.IsNullOrEmpty(localAppData))
+                {
+                    yield return Path.Combine(localAppData, "Programs", "uv", exeName);
+                }
+
+                if (!string.IsNullOrEmpty(programFiles))
+                {
+                    yield return Path.Combine(programFiles, "uv", exeName);
+                }
+            }
+
+            string pathEnv = Environment.GetEnvironmentVariable("PATH");
+            if (!string.IsNullOrEmpty(pathEnv))
+            {
+                foreach (string rawDir in pathEnv.Split(Path.PathSeparator))
+                {
+                    if (string.IsNullOrWhiteSpace(rawDir)) continue;
+                    string dir = rawDir.Trim();
+                    yield return Path.Combine(dir, exeName);
+
+                    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+                    {
+                        // Some PATH entries may already contain the file without extension
+                        yield return Path.Combine(dir, "uvx");
+                    }
+                }
+            }
+        }
+
         public void SetUvxPathOverride(string path)
         {
             if (string.IsNullOrEmpty(path))

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Helpers/WriteToConfigTests.cs

@@ -167,6 +167,40 @@ public void DoesNotAddEnvOrDisabled_ForTrae()
             AssertTransportConfiguration(unity, client);
         }
 
+        [Test]
+        public void ClaudeDesktop_UsesAbsoluteUvPath_WhenOverrideProvided()
+        {
+            var configPath = Path.Combine(_tempRoot, "claude-desktop.json");
+            WriteInitialConfig(configPath, isVSCode: false, command: "uvx", directory: "/old/path");
+
+            WithTransportPreference(false, () =>
+            {
+                EditorPrefs.SetString(EditorPrefKeys.UvxPathOverride, "/abs/mock/uvx");
+                try
+                {
+                    var client = new McpClient
+                    {
+                        name = "Claude Desktop",
+                        SupportsHttpTransport = false,
+                        StripEnvWhenNotRequired = true
+                    };
+
+                    InvokeWriteToConfig(configPath, client);
+
+                    var root = JObject.Parse(File.ReadAllText(configPath));
+                    var unity = (JObject)root.SelectToken("mcpServers.unityMCP");
+                    Assert.NotNull(unity, "Expected mcpServers.unityMCP node");
+                    Assert.AreEqual("/abs/mock/uvx", (string)unity["command"], "Claude Desktop should use absolute uvx path");
+                    Assert.IsNull(unity["env"], "Claude Desktop config should not include env block when not required");
+                    AssertTransportConfiguration(unity, client);
+                }
+                finally
+                {
+                    EditorPrefs.DeleteKey(EditorPrefKeys.UvxPathOverride);
+                }
+            });
+        }
+
         [Test]
         public void PreservesExistingEnvAndDisabled_ForKiro()
         {