Connect Claude Code to your email

Sickle is a remote MCP server: Claude Code talks to it over HTTP, so there is no package to install and no local process to keep running. Sign-in is OAuth, so there is no API key to put in your shell profile either. Once connected, Claude Code sees every mailbox in your Sickle account at once — Gmail, Outlook, iCloud, Fastmail, Yahoo and any IMAP host.

Before you start

• A Sickle account with at least one mailbox connected. If you do not have one yet, start a free trial and add your mailboxes in the Mac app or on the Mailboxes page. There is a step-by-step guide for Gmail, Outlook, iCloud, Fastmail and any other IMAP mailbox.
• Claude Code installed and signed in.

Add the server

Run this in any terminal:

claude mcp add --transport http --scope user sickle https://mcp.sickle.app

--transport http matters: without it Claude Code assumes a local command and the server will not start. --scope user makes Sickle available in every project. Leave it out and Sickle is added only to the project you ran the command in, which is Claude Code's default.

Sign in and approve access

Start Claude Code and type /mcp. Select sickle and choose Authenticate.

Your browser opens a Sickle sign-in page. Sign in and approve the permissions Claude Code asks for:

• email_read lets it list your mailboxes and folders, search and read messages.
• email_change lets it mark messages as read, move them between folders and move them to Trash.

You may also see email_send. Nothing uses it yet: Sickle has no tool that sends mail.

Claude Code stores the token and refreshes it on its own, so you sign in once. If you prefer to stay in the shell, claude mcp login sickle does the same thing.

Check it works

claude mcp list

Sickle should show ✔ Connected. Needs authentication means the sign-in step has not finished yet; run /mcp again.

Then ask Claude Code:

Which mailboxes can you see?

It calls list_accounts and names every mailbox in your Sickle account.

Share it with your team

To check Sickle into a repository for everyone who works on it, add it with --scope project instead. Claude Code writes it to .mcp.json at the project root:

{
  "mcpServers": {
    "sickle": {
      "type": "http",
      "url": "https://mcp.sickle.app"
    }
  }
}

Each person approves the server the first time Claude Code sees it, then signs in with their own Sickle account. Nobody sees anyone else's mail.

Troubleshooting

• "Failed to connect". Check the command used --transport http. If it did not, run claude mcp remove sickle and add it again.
• Sickle is missing in another project. It was added with the default local scope. Remove it and add it again with --scope user.
• Claude Code only sees some of your mailboxes. It sees exactly the mailboxes in your Sickle account. Add the others in the Mac app or on the Mailboxes page.

Disconnect

claude mcp remove sickle

This also deletes the stored token. To cut access from the Sickle side, revoke Claude Code on the Connect AI page in your dashboard; access it already holds ends within the hour.