dotenv v17 writes info message to stdout, breaking JSON-RPC in Claude Code MCP

[StefanGentz]

Bug Description

When starting the Postman MCP Server (Minimal) as an MCP server in Claude Code Desktop, the server fails to initialize with the following error:

MCP Postman MCP Server (Minimal): Invalid JSON-RPC message: [dotenv@17.2.2] injecting env (0) from .env -- tip: ⚙️ load multiple .env files with { path: ['.env.local', '.env'] }

Root Cause

In dotenv v17.x, dotenv.config() writes an informational message to stdout when no .env file is found. MCP servers communicate exclusively via stdout using JSON-RPC, so any non-JSON output on stdout breaks the protocol parser.

Affected file: dist/src/index.js, line 86:

dotenv.config();

Fix

Pass { quiet: true } to suppress the stdout output:

dotenv.config({ quiet: true });

Environment

• Postman MCP Server version: 2.3.6
• dotenv version: 17.2.2
• Claude Code Desktop on macOS (Apple Silicon)

Impact

The MCP server fails to start entirely — all Postman tools are unavailable until the local dist/src/index.js is patched manually.