Windows: SSH-based MCP servers require PROGRAMDATA environment variable

Issue

SSH connections fail when MCP servers are launched from Claude Desktop on Windows.

Common Use Case

Running an MCP server on a remote host (Raspberry Pi, home server, NAS, another PC on local network) and connecting to it via SSH from Windows Claude Desktop.

Root Cause

Claude Desktop launches MCP servers with a minimal environment missing PROGRAMDATA, which OpenSSH on Windows requires to locate system SSH configuration files.

Solution

Add PROGRAMDATA to the env configuration:

    {
      "mcpServers": {
        "my-remote-server": {
          "command": "C:\\WINDOWS\\System32\\OpenSSH\\ssh.exe",
          "args": [
            "user@remote-host.local",
            "-o", "StrictHostKeyChecking=accept-new",
            "-i", "C:\\Users\\username\\.ssh\\id_ed25519",
            "/path/to/remote/mcp-server/command"
          ],
          "env": {
            "PROGRAMDATA": "C:\\ProgramData"
          }
        }
      }
    }

Recommendation

1. Add this to Windows troubleshooting documentation
2. Consider passing PROGRAMDATA by default for Windows MCP server environments

Environment

• OS: Windows 11
• Claude Desktop
• OpenSSH (Windows built-in)
• Remote MCP server over SSH on local network

The issue does not name a documentation file or test. Locate the Windows troubleshooting documentation and verify how SSH-based MCP servers are configured there. Document the PROGRAMDATA environment setting and clarify whether passing it by default is a separate follow-up; done means the Windows SSH example covers this failure mode.