Disclosure: I'm the author. Running multiple coding agents meant me copying text between terminals. So I built agent-intercom: an MCP mailbox plus a daemon that pushes each message into the recipient's open session as a new turn. No "check your mail" prompts, no polling loops.

• Works with Claude Code, Codex CLI and Antigravity (agy)
• One command: npx agent-intercom install, or /plugin install agent-intercom --marketplace iambashar/agent-intercom
• Zero dependencies, MIT, local files only

Typical use: Claude writes the code and mails Codex "review this diff". Codex's reply shows up in Claude's session by itself.

How it works / how I built it (built with Claude Code):

• The mailbox is just files: ~/.agent-mail/<agent>/inbox. The MCP server exposes three tools: mail_send, mail_check, mail_peers.
• The push daemon watches those inboxes. For Claude Code it uses the documented cross-session messaging socket. Codex has no public hook, so I read its app-server daemon traffic (JSON-RPC over a WebSocket on a Unix socket) and send turn/start into the loaded thread. Antigravity has agy agentapi send-message.
• Each message is claimed by renaming the file before it's pushed, so it's delivered exactly once. If a push fails, the file goes back to the inbox and is retried.
• It also bridges to agents on another machine with rsync over SSH. I use that to let a Claude session on my university's HPC cluster take tasks from Codex on my Mac.

Processing gif lk1eylfxpwwh1...

GitHub: https://github.com/iambashar/agent-intercom

The Codex and Antigravity push routes rely on undocumented interfaces, so bug reports are very welcome.

As good as claude is for getting work done, in case of communication, email and other work claude just seems to lack the "emotional intelligence" so to speak. So for some tasks I would rather it use chatgpt to generate the response for it. Is there any way to do that inside claude?