Claude can't compose a poem and create a new text file on my desktop #3272

@itxn0tme

file is created but still not on the dekstop

I don't have access to write directly to that Windows path. My file system is isolated to the container environment, and I can only create files in /mnt/user-data/outputs/ which you can download.

That /mnt/user-data/outputs/ line is the giveaway. Claude wrote the poem inside its isolated container, not through the Filesystem MCP server. The file is "created," just not on your Windows Desktop.

The Connect to local MCP servers walkthrough uses macOS paths:

/Users/username/Desktop
/Users/username/Downloads

Claude Desktop on Windows 10 does not see those directories. If claude_desktop_config.json still has them (or only has your Caido server), the Filesystem tools never attach and Claude falls back to the container.

What to put in the config

Edit %APPDATA%\Claude\claude_desktop_config.json and give the server Windows paths (double backslashes in JSON):

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-filesystem",
        "C:\\Users\\YOURUSER\\Desktop",
        "C:\\Users\\YOURUSER\\Downloads"
      ]
    }
  }
}

Replace YOURUSER with the real account name (the folder under C:\Users). Keep your Caido entry next to filesystem if you still want that server. Both can live under mcpServers.

Do not use /mnt/c/Users/.... That is a WSL path. Claude Desktop is a native Windows app, and npx starts the Filesystem server on Windows, so the allowlist is C:\Users\.... Asking Claude to write to /mnt/c/... will be refused even after MCP is working.

Confirm the server is actually in the conversation

1. Fully quit Claude Desktop (tray icon too), then start it again.
2. In a new chat, open the connectors / hammer control and check that filesystem is listed and enabled.
3. Ask: What directories are you allowed to write to? You want C:\Users\YOURUSER\Desktop, not /mnt/user-data/outputs.
4. Then ask for the poem again, and approve the write_file tool prompt. If you never see that prompt, the MCP tools are still not attached.

If it still fails

• Run this in cmd.exe and fix any error it prints:

  npx -y @modelcontextprotocol/server-filesystem "C:\Users\YOURUSER\Desktop"

• Read %APPDATA%\Claude\logs\mcp.log and %APPDATA%\Claude\logs\mcp-server-filesystem.log. A working session logs initialize, tools/list, then tools/call for write_file.

• Node.js must be on PATH for the same Windows user that launches Claude. npx failing silently is the usual reason the connector shows "configured" but never exposes tools.

Once list_allowed_directories returns your real Desktop, the tutorial prompt (Can you write a poem and save it to my desktop?) writes poem.txt there.

That /mnt/user-data/outputs/ line is the giveaway. Claude wrote the poem inside an isolated container, not through the Filesystem MCP server. The file was created. It just is not on your Windows Desktop.

The official walkthrough uses macOS paths (/Users/username/Desktop). On Windows 10 + Claude Desktop you want a Windows path in the MCP config, and you want to confirm the Filesystem server is the one handling the write.

%APPDATA%\Claude\claude_desktop_config.json:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-filesystem",
        "C:\\Users\\x\\Desktop"
      ]
    }
  }
}

Notes that usually trip people up:

1. Fully quit Claude Desktop from the tray and reopen it after editing the JSON. A window close is not enough.
2. The allowed directory is an allowlist. If Desktop is not in args, the server will refuse C:\\Users\\x\\Desktop\\poem.txt.
3. If the model replies with /mnt/user-data/outputs/, it did not call the Filesystem MCP tool. That path is the artifact sandbox, not your PC. In that case the MCP server is either not connected, not selected for the chat, or the model ignored it. Check the MCP logs in Claude Desktop (Developer menu) for filesystem starting and tools/call hitting write_file.
4. WSL paths (/mnt/c/Users/...) only work if the MCP server itself is running inside WSL. Claude Desktop on Windows typically launches npx on Windows, so give it C:\\Users\\....

Quick sanity check after restart: ask "what filesystem tools do you have?" You should see read_file / write_file / list_directory from the filesystem server. Then "write a one-line test to C:\Users\x\Desktop\mcp-test.txt". If that lands, the poem prompt will too.

I have not reproduced this on your exact Caido + Claude Desktop setup. If filesystem tools never show up, paste the MCP server status from the Developer panel (redact tokens) and we can see whether it is config or the model bypassing the tool.