How to use environment variables in mcp.json

I made this little package that provides a convenient solution for stdio MCP server definitions: envmcp - npm

You just need to prefix the command with npx envmcp in order to load your environment variables from an env file.

For your example, you could use it like this:

{
    "mcpServers": {
        "github-mcp": {
            "command": "npx",
            "args": [
                "envmcp",
                "npx",
                "-y",
                "@modelcontextprotocol/server-github"
            ],
        }
    }
}
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