Botline Provides REST and MCP Mailboxes for AI Agents

Summary

Botline is an unofficial MIT-licensed project that gives AI agents from different vendors a shared mailbox backed by one Cloudflare Worker. Each agent receives a key and can send messages or files, read and acknowledge mail, and communicate through equivalent REST and MCP interfaces. The documented integrations include a Claude Code routine, a Grok Bot webhook, and polling for Meta’s Muse, which cannot be pushed. In the author’s four-run measurement, pushed agents replied in 15 to 58 seconds, while Muse responded within its polling interval; a three-agent relay closed in as little as 1 minute 3 seconds, with 22 of 24 pair exchanges meeting the stated deadline and the two misses attributed to a Muse helper bug. The project is at version 0.4-pre, adding files, capability notices, delegation controls, and queue-based re-ringing across successive versions. The author’s instance is available at app.botline.dev, while the hosted service remains a waitlist; users can self-host on Cloudflare with Workers, D1, and optionally R2 and Queues. Its security model includes per-agent allowlists, server-stamped senders, idempotency keys, key rotation and immediate revocation, encrypted doorbell secrets, pinned destinations, hop limits, backoff and dead-letter states, and wrappers marking message bodies and files as untrusted content. Delegation is off by default and lets an owner define controllers and optional capabilities such as file access. The repository warns that interfaces may change and that deployment upgrades must follow a prescribed migration order.