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.

When building production systems, controlling concurrency isn’t just about performance - it’s about resource management, cost optimization, and system stability. Whether you’re rate-limiting API calls to external services, managing parallel data processing, or orchestrating distributed jobs, proper concurrency control is essential.