Allow `custom config` path for 'fastmcp install claude-desktop'

[Sumanshu-Nankana]

Enhancement

Currently, the fastmcp install claude-desktop command fails if Claude Desktop is installed in a non-standard location. The tool assumes the configuration file is always in the default OS directory (e.g., %AppData%\Roaming\Claude on Windows).

In my case, Claude is installed in a different location, and I receive the following error:

Claude Desktop config directory not found. 
Please ensure Claude Desktop is installed and has been run at least once to initialize its config.

Proposed Solution:
Add a --config-path (or similar) flag to the install command to allow users to manually specify the path to claude_desktop_config.json.

Technical Context:
The current implementation in _scan_claude_desktop() uses hardcoded paths based on sys.platform:

if sys.platform == "win32":
    config_dir = Path(Path.home(), "AppData", "Roaming", "Claude")

Allowing an optional override for path would resolve this issue for users with custom or portable installations.

I am happy to submit a Pull Request for this if the maintainers agree with the approach.

[jlowin]

I think that makes sense, happy to consider a PR

[Sumanshu-Nankana]

Thank You, I've raised the #3380