MCP server can't find files given by relative paths: use absolute paths

Symptom

The server reads ./data.json and gets ENOENT: no such file or directory, open './data.json' (cwd is /), or a relative script path in args gives Error: Cannot find module '/proj/server.mjs'.

Environment and tested versions

Debian GNU/Linux 13 (trixie) x86_64, node 20.19.2, npm 11.21.1; client launched with cwd "/" to mimic a desktop client

• @modelcontextprotocol/sdk (TypeScript) 1.32.2
• node 20.19.2

Client used in the test: Reproduced with the official MCP TypeScript SDK stdio client (StdioClientTransport) 1.32.2 as a stand-in for a desktop app (Claude Desktop, Cursor, etc.), which can't run on the Linux test box. Not tested in the desktop app itself.

Root cause

Relative paths resolve against the client's working directory, not the server's folder or your project.

Fix steps

1. Use an absolute path for the server script in args.
2. Pass every file or directory the server reads as an absolute path, through args or env.
3. Restart the client.

Verification

Tested 31 Oct 2026 in a throwaway directory on a Linux box (fake credentials only). Before (A) and after the fix:

A relative data path:         CALL: "cwd=/ ENOENT: no such file or directory, open './data.json'"
B absolute via env DATA_FILE: CALL: {"greeting":"hello from data.json"}
C relative script in args:    Error: Cannot find module '/proj/server.mjs'
D absolute script path:       CONNECTED tools: read_data

Sources

• https://modelcontextprotocol.io/legacy/tools/debugging