The official MCP filesystem server (@modelcontextprotocol/server-filesystem) fails to access directories containing accented characters on macOS (e.g. Drive partagés from Google Drive).
Root cause: macOS stores filenames in Unicode NFD (decomposed) form where é = e + combining accent (U+0301), while user input and the MCP client send paths in NFC (composed) form where é = single codepoint U+00E9. The server compares these byte-different strings and rejects the path as "outside allowed directories".
This affects any macOS path with accented characters (French, German, Spanish, Korean, etc.).