Unable to launch AWS API MCP Server

[rkahnert-carson]

I am unable to launch the API MCP Server in Claud Desktop on Windows 10.
I tried the following:

• kill all python processes before installing
• delete the cache director manually - but it creates a new one every time
• ran uv cache clean
• uninstalled and reinstalled the plugin
• updated Claude Desktop

MCP Server version is 1.3.3. Claude for Windows Version 1.14271.0 (c8f4d8).
Any help would be appreciated.

2026-06-22T14:15:17.665Z [AWS API MCP Server] [info] Initializing server... { metadata: undefined }
2026-06-22T14:15:17.935Z [AWS API MCP Server] [info] Using MCP server command: uv.exe with args and path: {
  metadata: {
    args: [
      'run',
      '--directory',
      'C:\\Users\\<user>\\AppData\\Roaming\\Claude\\Claude Extensions\\ant.dir.gh.awslabs.aws-api-mcp-server',
      '--with',
      '.',
      '--python',
      '3.12',
      'python',
      '-m',
      'awslabs.aws_api_mcp_server.server',
      [length]: 10
    ],
    paths: [
      'C:\\Python313',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\Git\\cmd',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\Git\\mingw64\\bin',
      'C:\\Program Files\\Amazon Corretto\\jdk25.0.2_10\\bin',
      'C:\\Python313\\Scripts\\',
      'C:\\Python313\\',
      'C:\\Program Files\\Amazon Corretto\\jdk17.0.13_11\\bin',
      'C:\\Program Files\\Amazon Corretto\\jdk21.0.5_11\\bin',
      'C:\\Program Files\\Amazon Corretto\\jdk23.0.1_8\\bin',
      'C:\\Windows\\system32',
      'C:\\Windows',
      'C:\\Windows\\System32\\Wbem',
      'C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\',
      'C:\\Windows\\System32\\OpenSSH\\',
      'C:\\Program Files (x86)\\Symantec\\VIP Access Client\\',
      'C:\\Program Files\\dotnet\\',
      'C:\\Program Files\\Microsoft VS Code\\bin',
      'c:\\Tools\\Terraform',
      'C:\\ProgramData\\nvm',
      'C:\\Program Files\\nodejs',
      'C:\\Program Files\\Amazon\\SessionManagerPlugin\\bin\\',
      'C:\\Program Files\\Docker\\Docker\\resources\\bin',
      'C:\\Program Files\\Go\\bin',
      'C:\\Program Files\\PowerShell\\7\\',
      'C:\\Program Files\\Amazon\\AWSCLIV2\\',
      'C:\\Users\\<user>\\.local\\bin',
      'C:\\Users\\<user>\\AppData\\Local\\Microsoft\\WindowsApps',
      'C:\\Users\\<user>\\AppData\\Local\\JetBrains\\Toolbox\\scripts',
      'C:\\ProgramData\\chocoportable\\bin',
      'C:\\Tools\\nodejs',
      'c:\\Tools\\structurizr\\',
      'C:\\Users\\<user>\\AppData\\Local\\Microsoft\\WinGet\\Packages\\GitHub.Copilot_Microsoft.Winget.Source_8wekyb3d8bbwe',
      'C:\\Users\\<user>\\go\\bin',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\Git\\',
      'C:\\Users\\<user>\\AppData\\Local\\Microsoft\\WinGet\\Packages\\Anthropic.ClaudeCode_Microsoft.Winget.Source_8wekyb3d8bbwe',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\VSCodium\\bin',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\bd',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\Zed\\bin',
      'C:\\Users\\<user>\\AppData\\Local\\Programs\\Git\\bin\\bash.exe',
      'C:\\Users\\<user>\\AppData\\Local\\Microsoft\\WinGet\\Packages\\Schniz.fnm_Microsoft.Winget.Source_8wekyb3d8bbwe',
      [length]: 40
    ]
  }
} %o
2026-06-22T14:15:17.967Z [AWS API MCP Server] [info] Server started and connected successfully { metadata: undefined }
2026-06-22T14:15:17.969Z [AWS API MCP Server] [info] Message from client: {"method":"initialize","params":{"protocolVersion":"2025-11-25","capabilities":{"extensions":{"io.modelcontextprotocol/ui":{"mimeTypes":["text/html;profile=mcp-app"]}}},"clientInfo":{"name":"claude-ai","version":"0.1.0"}},"jsonrpc":"2.0","id":0} { metadata: undefined }
   Building awslabs-aws-api-mcp-server @ file:///C:/Users/<user>/AppData/Roaming/Claude/Claude%20Extensions/ant.dir.gh.awslabs.aws-api-mcp-server
   Building awslabs-aws-api-mcp-server @ file:///C:/Users/<user>/AppData/Roaming/Claude/Claude%20Extensions/ant.dir.gh.awslabs.aws-api-mcp-server
2026-06-22T14:15:19.718Z [AWS API MCP Server] [info] Server transport closed { metadata: undefined }
2026-06-22T14:15:19.718Z [AWS API MCP Server] [info] Client transport closed { metadata: undefined }
      Built awslabs-aws-api-mcp-server @ file:///C:/Users/<user>/AppData/Roaming/Claude/Claude%20Extensions/ant.dir.gh.awslabs.aws-api-mcp-server
error: Failed to install: jmespath-1.1.0-py3-none-any.whl (jmespath==1.1.0)
  Caused by: failed to remove directory `C:\Users\<user>\AppData\Local\uv\cache\builds-v0\.tmpuq9TmD\Lib\site-packages\jmespath-1.1.0.data`: The process cannot access the file because it is being used by another process. (os error 32)
2026-06-22T14:15:28.661Z [AWS API MCP Server] [info] Server transport closed { metadata: undefined }
2026-06-22T14:15:28.661Z [AWS API MCP Server] [info] Server transport closed unexpectedly, this is likely due to the process exiting early. If you are developing this MCP server you can add output to stderr (i.e. `console.error('...')` in JavaScript, `print('...', file=sys.stderr)` in python) and it will appear in this log. { metadata: undefined }
2026-06-22T14:15:28.661Z [AWS API MCP Server] [error] Server disconnected. For troubleshooting guidance, please visit our [debugging documentation](https://modelcontextprotocol.io/docs/tools/debugging) { metadata: { context: 'connection', stack: undefined } }
2026-06-22T14:15:28.662Z [AWS API MCP Server] [info] Client transport closed { metadata: undefined }
2026-06-22T14:15:28.662Z [AWS API MCP Server] [info] Client transport closed { metadata: undefined }