01The problem
Testing sign-up flows means burning a real inbox on OTP codes, and AI agents have no clean way to receive a verification email mid-task without someone forwarding it to them.
Developer tool · 2026 · LIVE
TossInbox
A CLI tool + MCP server for disposable email: it creates throwaway inboxes and catches OTP codes — for you and for AI agents.
The story
The problem, how I built it, and what came out of it.
02How I built it
A TypeScript CLI with seven free upstream providers (mail.tm, mail.gw, GuerrillaMail, tempmail.lol, temp-mail.io, tempmail.plus, maildrop), automatic failover when a provider is down, JSON output and exit codes 0–4 on every command — plus an MCP server (tossinbox-mcp), a GitHub Action, and a Homebrew tap, so agents and humans each install it their own way.
03The outcome
Live on npm as 0.1.6 — install it with npx, brew install mohamed-khairy-5i/tap/tossinbox, or a GitHub Action, and the docs site is live at tossinbox.pages.dev. Built end-to-end by a two-agent team — Hermes planned, Z.ai executed — proof that an agent pipeline can ship a real, tested developer tool.
Want something like this for your business?
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