Xcode 26.3 MCP server output missing `structredContent`

I am using official MCP SDK. According to official guide, Servers MUST provide structured results that conform to this schema. https://modelcontextprotocol.io/specification/draft/server/tools#output-schema

I could see output schema defined, but result have no structured content.

Current output schema:

{
  name: "XcodeListWindows",
  title: "List Windows",
  description: "Lists the current Xcode windows and their workspace information",
  inputSchema: {
    type: "object",
    properties: {
    },
    required: [
    ],
  },
  outputSchema: {
    type: "object",
    properties: {
      message: {
        description: "Description of all open Xcode windows",
        type: "string",
      },
    },
    required: [
      "message",
    ],
  },
}

Current response:

{
  "result": {
    "content": [
      {
        type: "text",
        text: "{\"message\":\"* tabIdentifier: windowtab1, workspacePath: \\xxx\\n* tabIdentifier: windowtab2, workspacePath: \\xxx\\n\"}",
      },
    ]
  }
}

Expected:

{
  "result": {
    "content": [
      {
        type: "text",
        text: "{\"message\":\"* tabIdentifier: windowtab1, workspacePath: \\xxx\\n* tabIdentifier: windowtab2, workspacePath: \\xxx\\n\"}",
      },
    ],
    "structuredContent": {
      "message": "* tabIdentifier: windowtab1, workspacePath: \\xxx\\n* tabIdentifier: windowtab2, workspacePath: \\xxx\\n",
    }
  }
}