Claude Code not using Tools / hot_reload doesn’t work

[torbenkeller]

I want to use Claude Code with this MCP, but it can not use the tools as expected. When I promt to use a tool, it tries, but then it fails:

⏺ flutterInspector:hot_reload_flutter (MCP)
  ⎿  Error: MCP error -32603: Error calling ext.mcpdevtools.hotReload: Unknown method "ext.mcpdevtools.hotReload".

These are the rpcs it gets:

⏺ flutterInspector:get_extension_rpcs (MCP)(port: 8181)
  ⎿  [
       "ext.ui.window.scheduleFrame",
       "ext.ui.window.reinitializeShader",
       "ext.ui.window.impellerEnabled",
       "ext.dart.io.httpEnableTimelineLogging",
       "ext.dart.io.getSocketProfile",
       "ext.dart.io.socketProfilingEnabled",
       "ext.dart.io.clearSocketProfile",
       "ext.dart.io.getVersion",
       "ext.dart.io.getHttpProfile",
       "ext.dart.io.getHttpProfileRequest",
       "ext.dart.io.clearHttpProfile",
       "ext.flutter.reassemble",
       "ext.flutter.exit",
       "ext.flutter.connectedVmServiceUri",
       "ext.flutter.activeDevToolsServerAddress",
       "ext.flutter.platformOverride",
       "ext.flutter.brightnessOverride",
       "ext.flutter.timeDilation",
       "ext.flutter.evict",
       "ext.flutter.profilePlatformChannels",
       "ext.flutter.invertOversizedImages",
       "ext.flutter.debugPaint",
       "ext.flutter.debugPaintBaselinesEnabled",
       "ext.flutter.repaintRainbow",
       "ext.flutter.debugDumpLayerTree",
       "ext.flutter.debugDisableClipLayers",
       "ext.flutter.debugDisablePhysicalShapeLayers",
       "ext.flutter.debugDisableOpacityLayers",
       "ext.flutter.debugDumpRenderTree",
       "ext.flutter.debugDumpSemanticsTreeInTraversalOrder",
       "ext.flutter.debugDumpSemanticsTreeInInverseHitTestOrder",
       "ext.flutter.profileRenderObjectPaints",
       "ext.flutter.profileRenderObjectLayouts",
       "ext.flutter.debugDumpApp",
       "ext.flutter.debugDumpFocusTree",
       "ext.flutter.showPerformanceOverlay",
       "ext.flutter.didSendFirstFrameEvent",
       "ext.flutter.didSendFirstFrameRasterizedEvent",
       "ext.flutter.profileWidgetBuilds",
       "ext.flutter.profileUserWidgetBuilds",
       "ext.flutter.debugAllowBanner",
       "ext.flutter.inspector.structuredErrors",
       "ext.flutter.inspector.show",
       "ext.flutter.inspector.trackRebuildDirtyWidgets",
       "ext.flutter.inspector.widgetLocationIdMap",
       "ext.flutter.inspector.trackRepaintWidgets",
       "ext.flutter.inspector.disposeAllGroups",
       "ext.flutter.inspector.disposeGroup",
       "ext.flutter.inspector.isWidgetTreeReady",
       "ext.flutter.inspector.disposeId",
       "ext.flutter.inspector.setPubRootDirectories",
       "ext.flutter.inspector.addPubRootDirectories",
       "ext.flutter.inspector.removePubRootDirectories",
       "ext.flutter.inspector.getPubRootDirectories",
       "ext.flutter.inspector.setSelectionById",
       "ext.flutter.inspector.getParentChain",
       "ext.flutter.inspector.getProperties",
       "ext.flutter.inspector.getChildren",
       "ext.flutter.inspector.getChildrenSummaryTree",
       "ext.flutter.inspector.getChildrenDetailsSubtree",
       "ext.flutter.inspector.getRootWidget",
       "ext.flutter.inspector.getRootWidgetSummaryTree",
       "ext.flutter.inspector.getRootWidgetSummaryTreeWithPreviews",
       "ext.flutter.inspector.getRootWidgetTree",
       "ext.flutter.inspector.getDetailsSubtree",
       "ext.flutter.inspector.getSelectedWidget",
       "ext.flutter.inspector.getSelectedSummaryWidget",
       "ext.flutter.inspector.isWidgetCreationTracked",
       "ext.flutter.inspector.screenshot",
       "ext.flutter.inspector.getLayoutExplorerNode",
       "ext.flutter.inspector.setFlexFit",
       "ext.flutter.inspector.setFlexFactor",
       "ext.flutter.inspector.setFlexProperties",
       "ext.mcp.toolkit.app_errors",
       "ext.mcp.toolkit.view_screenshots",
     "ext.mcp.toolkit.view_details"
     ]

When I tell it to use one, it does not execute it and says it has no tool for that:

⏺ Available Flutter extension RPCs including screenshot capabilities (ext.flutter.inspector.screenshot) and custom MCP toolkit extensions
  (ext.mcp.toolkit.view_screenshots, ext.mcp.toolkit.view_details, ext.mcp.toolkit.app_errors).

> now use "ext.mcp.toolkit.view_screenshots"

⏺ I can see that ext.mcp.toolkit.view_screenshots is available as an extension RPC, but I don't have a direct tool to call arbitrary Flutter
  extension RPCs. The Flutter Inspector tools I have access to are limited to specific predefined functions.

  However, I can try using the test custom extension tool which might be able to access these custom MCP toolkit extensions:

⏺ flutterInspector:test_custom_ext (MCP)
  ⎿ {
      "message": "No errors found. Here are possible reasons: \n1) There were really no errors. \n2) Errors occurred before they were captured by
     MCP server. \nWhat you can do (choose wisely): \n1) Try to reproduce action, which expected to cause errors. \n2) If errors still not
    visible, try to navigate to another screen and back. \n3) If even then errors still not visible, try to restart app.",
      "errors": [],
      "type": "_extensionType",
      "method": "ext.mcp.toolkit.app_errors"
    }

[Arenukvern]

update:

I made several tests with the server, and I think that in nearest time (maybe one-two days) will migrate to official dart_mcp package from typescript - it will allow to get more tooling support and will make easier to setup and hot reload function will work the same way as Flutter team made in their package.

But for other tools, I will prefer to use MCPToolkit way, because yesterday I’ve completed the prototype of dynamic tools registrations, I think it will be much more customizable and maintainable..

#42

[Arenukvern]

hey @torbenkeller

I’ve just added new Dart server implementation, including hot reload.
Please see https://github.com/Arenukvern/mcp_flutter/blob/main/mcp_server_dart/README.md if you interested to test:)

Note:
the setup config is a little bit different, please see README above to setup.

Note 2:
resources may not work at Claude code, so if they will not work, please add
--no-resources
argument to mcp config, and then resources will be available as tools.