Sickle

Sickle's remote MCP server (https://mcp.sickle.app) connects every mailbox you own to Claude, Claude Code, Cursor, Codex or any MCP client: Gmail and Outlook over OAuth, iCloud, Fastmail, Yahoo and any IMAP server, all at once. Your agent can list, search, read, mark, move, trash, draft and send across all of them, and work with attachments. OAuth with separate read, change and send scopes, revocable per client. Works from macOS, Windows or Linux; nothing to install. Sickle is also a native macOS mail client for the same accounts: no cap on accounts, a colour per mailbox, an email cleaner for one-time codes and subscription junk, and keyboard/Vim navigation. One subscription covers the app and the connector: £8.99/month or £30/year, 7 days free.