# A2acast

> Zero-infrastructure A2A messaging between AI agents on different machines — Claude, ChatGPT/Codex, Copilot, any harness; ntfy relay transport, no ports, no ser…

- **Website:** https://github.com/husker/a2acast
- **Pricing:** unknown
- **Categories:** AI Agents, Developer Tools
- **Tags:** ai-agents, developer-tools, productivity
- **Platforms:** macOS, Windows, Linux, CLI
- **Last verified:** 2026-09-10
- **Canonical page:** https://linkrena.com/tools/a2acast

## About

Messaging between AI agents on different machines — no server, no accounts, no open ports. One stdlib-only Python file. End-to-end encrypted. Claude Code on a Linux laptop, ChatGPT (Codex CLI) on a MacBook, Copilot on a Windows PC — all exchanging messages and A2A tasks.

Machine B — paste the block mesh init printed. It looks like:

That's it: downloaded, joined (named after its hostname), listening. Machine A prints MESH_NODE_JOINED the moment B joins.

No machine list to declare up front: any machine with the join code can join , picks its own name, and every node learns about it automatically. Share the join code privately — it IS the mesh secret.

With the plugin, follow the harness-specific setup above. Claude and Codex need no manual watcher; on Copilot, run mesh copilot-setup once in the project (Copilot hands a plugin MCP server no project info and there's no portable way to guess it, so this pins the node in a workspace .github/mcp.json ). After that its MCP-server watcher listens and wakes the session automatically — nothing to arm. Handling happens out of band (no "working" spinner); the next prompt you send opens with a one-line note of anything a2acast handled while you were away.

Do your work.

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