Description

The one-click "Install on VS Code" buttons in the README generate incorrect MCP server configurations for Windows users. The generated configuration uses uvx with package names that fail to start on Windows.

Affected Servers

This issue affects most (possibly all) AWS MCP servers that use the one-click installation link format. Specifically tested with AWS Pricing MCP Server, but the pattern suggests it's widespread.

Installation Method

Using the one-click installation button from README.md:

https://insiders.vscode.dev/redirect/mcp/install?name=AWS%20Pricing%20MCP%20Server&config=%7B%22command%22%3A%22uvx%22%2C%22args%22%3A%5B%22awslabs.aws-pricing-mcp-server%40latest%22%5D%2C%22env%22%3A%7B%22FASTMCP_LOG_LEVEL%22%3A%22ERROR%22%2C%22AWS_PROFILE%22%3A%22your-aws-profile%22%2C%22AWS_REGION%22%3A%22us-east-1%22%7D%2C%22disabled%22%3Afalse%2C%22autoApprove%22%3A%5B%5D%7D

Generated Configuration (Incorrect)

{
  "AWS Pricing MCP Server": {
    "command": "uvx",
    "args": [
      "awslabs.aws-pricing-mcp-server@latest"
    ],
    "env": {
      "FASTMCP_LOG_LEVEL": "ERROR",
      "AWS_PROFILE": "your-aws-profile",
      "AWS_REGION": "us-east-1"
    },
    "disabled": false,
    "autoApprove": [],
    "type": "stdio"
  }
}

Error Logs

2025-11-11 09:29:27.253 [info] Connection state: Starting
2025-11-11 09:29:27.255 [info] Connection state: Running
2025-11-11 09:29:28.576 [warning] [server stderr] error: Failed to spawn: `awslabs.aws-pricing-mcp-server`
2025-11-11 09:29:28.578 [warning] [server stderr]   Caused by: program not found
2025-11-11 09:29:28.601 [info] Connection state: Error Process exited with code 2

Root Cause

On Windows, uvx cannot directly execute Python packages. The configuration needs to use uv tool run with the .exe extension for the executable.

Working Configuration (Correct for Windows)

{
  "AWS Pricing MCP Server": {
    "command": "uv",
    "args": [
      "tool",
      "run",
      "--from",
      "awslabs.aws-pricing-mcp-server@latest",
      "awslabs.aws-pricing-mcp-server.exe"
    ],
    "env": {
      "FASTMCP_LOG_LEVEL": "ERROR",
      "AWS_PROFILE": "your-aws-profile",
      "AWS_REGION": "us-east-1"
    },
    "disabled": false,
    "autoApprove": [],
    "type": "stdio"
  }
}

Suggested Fix

The one-click installation links should detect the user's OS or provide platform-specific installation buttons. Alternatively, the README should prominently document the Windows-specific configuration format (which is mentioned in the README but not reflected in the one-click install buttons).

Reference

The correct Windows format is documented in the README under "For Windows" section, but the one-click installation buttons don't follow this format.

Environment

• OS: Windows 11
• VS Code Version: Latest Insiders
• uv installed via: Standard installation
• Python: 3.10+

Impact

Windows users clicking the "Install on VS Code" buttons get non-functional configurations and must manually troubleshoot and fix the configuration file.