Email clients have GUIs. AI agents need APIs. Emacs users need text interfaces. macOS Mail.app has neither.

mail-app-cli solves this by wrapping Mail.app in a scriptable command-line interface. Complete access to accounts, mailboxes, messages, and attachments. JSON output. No OAuth dance. No API tokens. If it’s in Mail.app, you can script it.

The Problem It Solves

For Emacs users: Read and manage email without leaving your editor. mail-app-wrap provides the Emacs interface. mail-app-cli provides the engine.

MCP (Model Context Protocol) servers give AI agents access to tools. Tempting to build MCP servers directly. Better approach: build good CLIs first, then wrap them as MCPs.

Good CLIs are multi-interface. Usable from shell. Scriptable. Composable with pipes. Testable standalone. Accessible to humans without AI. Then wrap as MCP for AI agent access.

MCP-first locks you to the MCP protocol. CLI-first gives you flexibility.

The Multi-Interface Advantage

A good CLI like mail-app-cli works in multiple contexts: