Install Inbox Check — Email Deliverability Test in Claude Code

What you need first

• Claude Code, installed.
• Node.js, which gives the npx command the server starts with.
• Your own value for YOUR_INBOX_CHECK_API_KEY.

Steps

1. Run this in a terminal, in the project folder. It adds the server for you in that project; put --scope user after claude mcp add to have it in every project.

claude mcp add --env INBOX_CHECK_API_KEY=YOUR_INBOX_CHECK_API_KEY --transport stdio inbox-check -- npx -y [email protected]

2. Replace YOUR_INBOX_CHECK_API_KEY with your own value.
3. Start Claude Code and type /mcp: the server is listed with its state.

Check it worked

Ask Claude Code: List the tools of inbox-check.

If it does not start

spawn npx ENOENT

Node.js is not on the PATH that Claude Code sees. Install it, or write the full path of npx in the config.

The server starts, but its tools fail

A YOUR_… placeholder is still in the config, or its value is wrong.