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mcp/harbor
Gemini CLI

MailboxValidator for Gemini CLI

io.github.mailboxvalidator/mcp-mailboxvalidator

Email validation MCP server using the MailboxValidator API. It can validate email addresses.

client:Gemini CLI transport:stdio runtime:npm

Install MailboxValidator in Gemini CLI

~/.gemini/settings.json · windows: %USERPROFILE%\.gemini\settings.json

Held in this page only — never stored, logged, or sent anywhere but back to your screen. 

{
  "mcpServers": {
    "mcp-mailboxvalidator": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-mailboxvalidator"
      ],
      "env": {
        "MAILBOXVALIDATOR_API_KEY": "<MAILBOXVALIDATOR_API_KEY>"
      }
    }
  }
}

Gemini expands $VAR and ${VAR} inside env values, so a secret can live in your shell rather than this file. Gemini CLI docs

MailboxValidator in other clients

MailboxValidator MCP server