MuhammadTalhaMT/claude-intercom

No install — npx fetches it on first run on both machines; you need Bun on PATH (Bun.serve powers the HTTP listener).
Claude Code v2.1.80 or later is required; both machines must reach each other over HTTP (Tailscale recommended).
Source: git clone https://github.com/MuhammadTalhaMT/claude-intercom.git && bun install, then point "command": "bun" at intercom.ts.
Configure both sides in .mcp.json with MY_ROLE, REMOTE_HOST (host:port or tunnel URL), INTERCOM_SECRET (must match), INTERCOM_PORT (default 8788).

Usage

• •Start on both machines: claude --dangerously-load-development-channels server:intercom.
• •In either session, ask: "Send a message to the other developer asking what API endpoints are available" — Claude uses send_message, the other Claude receives it as a channel notification.
• •Use check_message to ask whether a reply is slow or never coming; states are sent (no ack), delivered-to-process, or answered.
• •Options: send_message message + optional replyTo and per-message expectReplyWithin ("30s", "5m", "2h"); /health returns status+role+version.

Key features

• ✓send_message (fire-and-forget with an id; ack doesn't claim the other developer read it) and check_message with per-message overdue windows.
• ✓Shared-secret HTTP auth (X-Intercom-Secret; 401 without it); inbound messages treated as data, not instructions — slash commands stay inert.
• ✓No data persistence (messages forwarded in real time), configurable listen port and outbound send timeout.
• ✓Tailscale recommended (stable tailnet addresses, no public listener); ngrok auto-detected with HTTPS switch.
• ✓Works on native Windows, between two different people, and without transiting Anthropic servers — the gaps the native feature doesn't cover; MIT.

Best for

Two developers (e.g. backend + frontend) with separate Claude Code sessions who want a private hotline — especially on Windows, between different users, or when messages must not transit Anthropic servers.

Caveats

• ⚠Superseded for the common case: since 2026-08-07, Claude Code v2.1.224 ships native cross-session messaging (ListAgents/SendMessage) — the README recommends native messaging for same-user macOS/Linux sessions.
• ⚠Security warning: intercom is a raw pipe with a shared secret — anyone holding your secret and address can push text into your session; native messaging enforces in/outbound controls, this does not.
• ⚠Does not guarantee delivery to the other developer — only that the remote accepted it; replies are matched via replyTo.
• ⚠Uses an experimental channel mechanism (--dangerously-load-development-channels); the stdio leg is what attaches it to a live Claude Code session.