Add --offline to uvx launches for faster startup (#760)

MCPForUnity/Editor/Clients/McpClientConfiguratorBase.cs

@@ -741,7 +741,7 @@ public override void Configure()
         public void ConfigureWithCapturedValues(
             string projectDir, string claudePath, string pathPrepend,
             bool useHttpTransport, string httpUrl,
-            string uvxPath, string fromArgs, string packageName, bool shouldForceRefresh,
+            string uvxPath, string fromArgs, string packageName, string uvxDevFlags,
             string apiKey,
             Models.ConfiguredTransport serverTransport)
         {
@@ -752,7 +752,7 @@ public void ConfigureWithCapturedValues(
             else
             {
                 RegisterWithCapturedValues(projectDir, claudePath, pathPrepend,
-                    useHttpTransport, httpUrl, uvxPath, fromArgs, packageName, shouldForceRefresh,
+                    useHttpTransport, httpUrl, uvxPath, fromArgs, packageName, uvxDevFlags,
                     apiKey, serverTransport);
             }
         }
@@ -763,7 +763,7 @@ public void ConfigureWithCapturedValues(
         private void RegisterWithCapturedValues(
             string projectDir, string claudePath, string pathPrepend,
             bool useHttpTransport, string httpUrl,
-            string uvxPath, string fromArgs, string packageName, bool shouldForceRefresh,
+            string uvxPath, string fromArgs, string packageName, string uvxDevFlags,
             string apiKey,
             Models.ConfiguredTransport serverTransport)
         {
@@ -789,10 +789,8 @@ private void RegisterWithCapturedValues(
             }
             else
             {
-                // Note: --reinstall is not supported by uvx, use --no-cache --refresh instead
-                string devFlags = shouldForceRefresh ? "--no-cache --refresh " : string.Empty;
                 // Use --scope local to register in the project-local config, avoiding conflicts with user-level config (#664)
-                args = $"mcp add --scope local --transport stdio UnityMCP -- \"{uvxPath}\" {devFlags}{fromArgs} {packageName}";
+                args = $"mcp add --scope local --transport stdio UnityMCP -- \"{uvxPath}\" {uvxDevFlags}{fromArgs} {packageName}";
             }
 
             // Remove any existing registrations from ALL scopes to prevent stale config conflicts (#664)
@@ -867,9 +865,7 @@ private void Register()
             else
             {
                 var (uvxPath, _, packageName) = AssetPathUtility.GetUvxCommandParts();
-                // Use central helper that checks both DevModeForceServerRefresh AND local path detection.
-                // Note: --reinstall is not supported by uvx, use --no-cache --refresh instead
-                string devFlags = AssetPathUtility.ShouldForceUvxRefresh() ? "--no-cache --refresh " : string.Empty;
+                string devFlags = AssetPathUtility.GetUvxDevFlags();
                 string fromArgs = AssetPathUtility.GetBetaServerFromArgs(quoteFromPath: true);
                 // Use --scope local to register in the project-local config, avoiding conflicts with user-level config (#664)
                 args = $"mcp add --scope local --transport stdio UnityMCP -- \"{uvxPath}\" {devFlags}{fromArgs} {packageName}";
@@ -977,9 +973,7 @@ public override string GetManualSnippet()
                 return "# Error: Configuration not available - check paths in Advanced Settings";
             }
 
-            // Use central helper that checks both DevModeForceServerRefresh AND local path detection.
-            // Note: --reinstall is not supported by uvx, use --no-cache --refresh instead
-            string devFlags = AssetPathUtility.ShouldForceUvxRefresh() ? "--no-cache --refresh " : string.Empty;
+            string devFlags = AssetPathUtility.GetUvxDevFlags();
             string fromArgs = AssetPathUtility.GetBetaServerFromArgs(quoteFromPath: true);
 
             return "# Register the MCP server with Claude Code:\n" +

MCPForUnity/Editor/Helpers/AssetPathUtility.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
 using MCPForUnity.Editor.Constants;
 using MCPForUnity.Editor.Services;
@@ -438,6 +439,95 @@ public static bool ShouldForceUvxRefresh()
             return IsLocalServerPath();
         }
 
+        private static bool _offlineCacheResult;
+        private static double _offlineCacheTimestamp = -999;
+        private const double OfflineCacheTtlSeconds = 30.0;
+
+        /// <summary>
+        /// Determines whether uvx should use --offline mode for faster startup.
+        /// Runs a lightweight probe (uvx --offline ... mcp-for-unity --help) with a 3-second timeout
+        /// to check if the package is already cached. If cached, --offline skips the network
+        /// dependency check that can hang for 30+ seconds on poor connections.
+        /// Returns false if force refresh is enabled (new download needed).
+        /// The result is cached for 30 seconds to avoid redundant subprocess spawns.
+        /// Must be called on the main thread (reads EditorPrefs).
+        /// </summary>
+        public static bool ShouldUseUvxOffline()
+        {
+            if (ShouldForceUvxRefresh())
+                return false;
+            return GetCachedOfflineProbeResult();
+        }
+
+        private static bool GetCachedOfflineProbeResult()
+        {
+            double now = EditorApplication.timeSinceStartup;
+            if (now - _offlineCacheTimestamp < OfflineCacheTtlSeconds)
+                return _offlineCacheResult;
+
+            bool result = RunOfflineProbe();
+            _offlineCacheResult = result;
+            _offlineCacheTimestamp = now;
+            return result;
+        }
+
+        private static bool RunOfflineProbe()
+        {
+            try
+            {
+                string uvxPath = MCPServiceLocator.Paths.GetUvxPath();
+                if (string.IsNullOrEmpty(uvxPath))
+                    return false;
+
+                string fromArgs = GetBetaServerFromArgs(quoteFromPath: false);
+                string probeArgs = string.IsNullOrEmpty(fromArgs)
+                    ? "--offline mcp-for-unity --help"
+                    : $"--offline {fromArgs} mcp-for-unity --help";
+
+                return ExecPath.TryRun(uvxPath, probeArgs, null, out _, out _, timeoutMs: 3000);
+            }
+            catch
+            {
+                return false;
+            }
+        }
+
+        /// <summary>
+        /// Returns the uvx dev-mode flags as a single string for command-line builders.
+        /// Returns "--no-cache --refresh " if force refresh is enabled,
+        /// "--offline " if the cache is warm, or string.Empty otherwise.
+        /// Must be called on the main thread (reads EditorPrefs).
+        /// </summary>
+        public static string GetUvxDevFlags()
+        {
+            bool forceRefresh = ShouldForceUvxRefresh();
+            return GetUvxDevFlags(forceRefresh, !forceRefresh && GetCachedOfflineProbeResult());
+        }
+
+        /// <summary>
+        /// Returns the uvx dev-mode flags from pre-captured bool values.
+        /// Use this overload when values were captured on the main thread for background use.
+        /// </summary>
+        public static string GetUvxDevFlags(bool forceRefresh, bool useOffline)
+        {
+            if (forceRefresh) return "--no-cache --refresh ";
+            if (useOffline) return "--offline ";
+            return string.Empty;
+        }
+
+        /// <summary>
+        /// Returns the uvx dev-mode flags as a list of individual arguments.
+        /// Suitable for callers that build argument lists (ConfigJsonBuilder, CodexConfigHelper).
+        /// Must be called on the main thread (reads EditorPrefs).
+        /// </summary>
+        public static IReadOnlyList<string> GetUvxDevFlagsList()
+        {
+            bool forceRefresh = ShouldForceUvxRefresh();
+            if (forceRefresh) return new[] { "--no-cache", "--refresh" };
+            if (GetCachedOfflineProbeResult()) return new[] { "--offline" };
+            return Array.Empty<string>();
+        }
+
         /// <summary>
         /// Returns true if the server URL is a local path (file:// or absolute path).
         /// </summary>

MCPForUnity/Editor/Helpers/CodexConfigHelper.cs

@@ -17,14 +17,11 @@ namespace MCPForUnity.Editor.Helpers
     /// </summary>
     public static class CodexConfigHelper
     {
-        private static void AddDevModeArgs(TomlArray args)
+        private static void AddUvxModeFlags(TomlArray args)
         {
             if (args == null) return;
-            // Use central helper that checks both DevModeForceServerRefresh AND local path detection.
-            // Note: --reinstall is not supported by uvx, use --no-cache --refresh instead
-            if (!AssetPathUtility.ShouldForceUvxRefresh()) return;
-            args.Add(new TomlString { Value = "--no-cache" });
-            args.Add(new TomlString { Value = "--refresh" });
+            foreach (var flag in AssetPathUtility.GetUvxDevFlagsList())
+                args.Add(new TomlString { Value = flag });
         }
 
         public static string BuildCodexServerBlock(string uvPath)
@@ -53,7 +50,7 @@ public static string BuildCodexServerBlock(string uvPath)
                 unityMCP["command"] = uvxPath;
 
                 var args = new TomlArray();
-                AddDevModeArgs(args);
+                AddUvxModeFlags(args);
                 // Use centralized helper for beta server / prerelease args
                 foreach (var arg in AssetPathUtility.GetBetaServerFromArgsList())
                 {
@@ -205,7 +202,7 @@ private static TomlTable CreateUnityMcpTable(string uvPath)
                 unityMCP["command"] = new TomlString { Value = uvxPath };
 
                 var argsArray = new TomlArray();
-                AddDevModeArgs(argsArray);
+                AddUvxModeFlags(argsArray);
                 // Use centralized helper for beta server / prerelease args
                 foreach (var arg in AssetPathUtility.GetBetaServerFromArgsList())
                 {

MCPForUnity/Editor/Helpers/ConfigJsonBuilder.cs

@@ -180,12 +180,8 @@ private static IList<string> BuildUvxArgs(string fromUrl, string packageName)
             // Keep ordering consistent with other uvx builders: dev flags first, then --from <url>, then package name.
             var args = new List<string>();
 
-            // Use central helper that checks both DevModeForceServerRefresh AND local path detection.
-            if (AssetPathUtility.ShouldForceUvxRefresh())
-            {
-                args.Add("--no-cache");
-                args.Add("--refresh");
-            }
+            foreach (var flag in AssetPathUtility.GetUvxDevFlagsList())
+                args.Add(flag);
 
             // Use centralized helper for beta server / prerelease args
             foreach (var arg in AssetPathUtility.GetBetaServerFromArgsList())

MCPForUnity/Editor/Migrations/StdIoVersionMigration.cs

@@ -74,6 +74,12 @@ private static void RunMigrationIfNeeded()
                     if (!ConfigUsesStdIo(configurator.Client))
                         continue;
 
+                    // Skip clients that don't support the current transport setting —
+                    // Configure() would throw (e.g., Claude Desktop when HTTP is enabled).
+                    bool useHttp = EditorConfigurationCache.Instance.UseHttpTransport;
+                    if (useHttp && !configurator.Client.SupportsHttpTransport)
+                        continue;
+
                     MCPServiceLocator.Client.ConfigureClient(configurator);
                     touchedAny = true;
                 }

MCPForUnity/Editor/Services/Server/ServerCommandBuilder.cs

@@ -46,9 +46,7 @@ public bool TryBuildCommand(out string fileName, out string arguments, out strin
                 return false;
             }
 
-            // Use central helper that checks both DevModeForceServerRefresh AND local path detection.
-            // Note: --reinstall is not supported by uvx, use --no-cache --refresh instead
-            string devFlags = AssetPathUtility.ShouldForceUvxRefresh() ? "--no-cache --refresh " : string.Empty;
+            string devFlags = AssetPathUtility.GetUvxDevFlags();
             bool projectScopedTools = EditorPrefs.GetBool(
                 EditorPrefKeys.ProjectScopedToolsLocalHttp,
                 true

MCPForUnity/Editor/Windows/Components/ClientConfig/McpClientConfigSection.cs

@@ -304,7 +304,7 @@ private void ConfigureClaudeCliAsync(IMcpClientConfigurator client)
             string httpUrl = HttpEndpointUtility.GetMcpRpcUrl();
             var (uvxPath, _, packageName) = AssetPathUtility.GetUvxCommandParts();
             string fromArgs = AssetPathUtility.GetBetaServerFromArgs(quoteFromPath: true);
-            bool shouldForceRefresh = AssetPathUtility.ShouldForceUvxRefresh();
+            string uvxDevFlags = AssetPathUtility.GetUvxDevFlags();
             string apiKey = EditorPrefs.GetString(EditorPrefKeys.ApiKey, string.Empty);
 
             // Compute pathPrepend on main thread
@@ -331,7 +331,7 @@ private void ConfigureClaudeCliAsync(IMcpClientConfigurator client)
                         cliConfigurator.ConfigureWithCapturedValues(
                             projectDir, claudePath, pathPrepend,
                             useHttpTransport, httpUrl,
-                            uvxPath, fromArgs, packageName, shouldForceRefresh,
+                            uvxPath, fromArgs, packageName, uvxDevFlags,
                             apiKey, serverTransport);
                     }
                     return (success: true, error: (string)null);

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

@@ -0,0 +1,38 @@
+using NUnit.Framework;
+using MCPForUnity.Editor.Helpers;
+using MCPForUnity.Editor.Constants;
+using UnityEditor;
+
+namespace MCPForUnityTests.Editor.Helpers
+{
+    public class AssetPathUtilityOfflineTests
+    {
+        private bool _originalForceRefresh;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _originalForceRefresh = EditorPrefs.GetBool(EditorPrefKeys.DevModeForceServerRefresh, false);
+        }
+
+        [TearDown]
+        public void TearDown()
+        {
+            EditorPrefs.SetBool(EditorPrefKeys.DevModeForceServerRefresh, _originalForceRefresh);
+        }
+
+        [Test]
+        public void ShouldUseUvxOffline_WhenForceRefreshEnabled_ReturnsFalse()
+        {
+            EditorPrefs.SetBool(EditorPrefKeys.DevModeForceServerRefresh, true);
+            Assert.IsFalse(AssetPathUtility.ShouldUseUvxOffline());
+        }
+
+        [Test]
+        public void ShouldUseUvxOffline_DoesNotThrow()
+        {
+            EditorPrefs.SetBool(EditorPrefKeys.DevModeForceServerRefresh, false);
+            Assert.DoesNotThrow(() => AssetPathUtility.ShouldUseUvxOffline());
+        }
+    }
+}

TestProjects/UnityMCPTests/Assets/Tests/EditMode/Tools/ManageGameObjectTests.cs

@@ -323,10 +323,11 @@ public void SetComponentProperties_ContinuesAfterException()
             };
 
             // Expect the error logs from the invalid property
-            // Note: PropertyConversion logs "Error converting token to..." when conversion fails
+            // Note: PropertyConversion logs "Error converting token to..." when conversion fails,
+            // then ComponentOps catches the exception and returns an error string (no second Error log).
+            // GameObjectComponentHelpers logs the failure as a warning.
             LogAssert.Expect(LogType.Error, new System.Text.RegularExpressions.Regex("Error converting token to UnityEngine.Vector3"));
-            LogAssert.Expect(LogType.Error, new System.Text.RegularExpressions.Regex(@"\[SetProperty\].*Failed to set 'velocity'"));
-            LogAssert.Expect(LogType.Warning, new System.Text.RegularExpressions.Regex("Property 'velocity' not found"));
+            LogAssert.Expect(LogType.Warning, new System.Text.RegularExpressions.Regex(@"\[ManageGameObject\].*Failed to set property 'velocity'"));
 
             // Act
             var result = ManageGameObject.HandleCommand(setPropertiesParams);