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Set-up documentation

Connect your mailbox to Cursor

Cursor takes a remote MCP server in mcpServers with a url and nothing else. Its own page documents a type key for local servers only, so do not add one.

Time About 2 minutes
Where Customize in the sidebar, or the file directly
It needs URL only, probably
Top-level key mcpServers
URL key url

The configuration

Two lines that matter, and no credential in either of them.

~/.cursor/mcp.json Every project 
{
  "mcpServers": {
    "work-mail": {
      "url": "https://mcp.mailbox-mcp.com/db/mcp/YOUR-MAILBOX-KEY"
    }
  }
}

Rename work-mail to whatever you will recognise. It is the identifier the tools are namespaced under, so letters, numbers and hyphens only.

Do not add a type key

If you are copying a snippet from somewhere else, this is the line to delete. You will see "type": "http" in a lot of MCP documentation, and it is correct for VS Code and for Claude Code. Cursor does not document it for a remote server at all.

Its own page names three transports in prose, then gives a field table for a remote server containing exactly three keys: url, headers and auth. type appears in the STDIO section, describing a local process. Adding one to a remote entry is copying a line from a different program's vocabulary.

Nor a headers block

headers is for a server that authenticates with a static token. This one signs you in instead, so leaving it out is what you want. A token pasted here is a credential in a file in your home directory that did not need to exist.

Which file, and for which projects

File Applies to
~/.cursor/mcp.json Every project you open. This is the one most people want for a mailbox.
.cursor/mcp.json One project, from its root. Useful for a shared team mailbox on a repository.

There is also Customize in the sidebar, which edits the same thing without you finding the file. In an organisation, MCP configuration can be governed centrally under Team Settings, so if the server is refused rather than failing, that is worth checking before anything on this page.

Cursor's documentation gives no separate Windows path for the global file. The %USERPROFILE% form you will find elsewhere is somebody's inference rather than the vendor's, which is why it is in the unconfirmed list at the foot of this page rather than in the table above.

Signing in

Cursor should prompt you to authenticate the first time the server is reached. It opens the control panel, you sign in, and you choose which mailbox this connector opens.

If it does not prompt, and instead reports that the server is unauthorised, then this build of Cursor cannot register a client on its own and needs a token. Create an access token in the control panel and add a headers block:

~/.cursor/mcp.json Fallback: token instead of sign-in 
{
  "mcpServers": {
    "work-mail": {
      "url": "https://mcp.mailbox-mcp.com/db/mcp/YOUR-MAILBOX-KEY",
      "headers": {
        "Authorization": "Bearer YOUR-ACCESS-TOKEN"
      }
    }
  }
}

Try it without first. We would rather tell you the sign-in might not work than tell you to paste a credential you may not need, and if it turns out your version needs one, we would like to know so this page can say so plainly.

Check that it worked

Try this first

Find the email where someone reported this bug, and show me what they actually said before I read the stack trace.

The reason a mailbox in an editor is worth having at all: the report and the code in one place. Nothing is marked read by asking, so the message stays unread in your own client.

The free tier is 5 MCP calls a day on any mailbox, with no card, which is enough to paste the block above and see whether this is useful to you.

Connect a mailbox Sign in

Where to go next

VS Code takes a different top-level key and Zed a third, so do not reuse this block in either. The key table has all of them side by side.

What we could not confirm
  • Whether Cursor does RFC 7591 dynamic client registration, as opposed to only the static auth object its docs describe. Its page says it "supports OAuth for servers that require it" and stops there.
  • The Windows path for the global file. Cursor gives no separate Windows path, so the %USERPROFILE% form you will find elsewhere is somebody's inference and not the vendor's.

Read 30 August 2026 Every value on this page came off Cursor documentation: Model Context Protocol on that day. If it has changed since, tell us and we will read it again.

By Mark McNeece, Founder Published Last reviewed Editorial standards