Claude Code now lets your AI agents message each other across sessions
Message your other Claude Code sessions
Anthropic's Claude Code has introduced cross-session messaging, enabling one Claude session to send a text message to another session. This allows Claude to warn a session when a change breaks its work, or to hand off a finding that unblocks another session. Messages are plain text only, not conversation history. Claude discovers targets via ListAgents and sends via SendMessage. Delivery is not guaranteed; receiving sessions can accept, hold, or refuse messages based on settings and permission modes. Cross-machine replies are one-way unless Remote Control is connected.
A message is a piece of text one Claude writes to another, never conversation history or files.
- eigenblake
Like some others, I also built this myself. Overly simply, with tmux, a memory tree, and handoff files and an orchestrator. And yet for how simple it was, it was so effective at minimizing the amount of duplicate context. It's like having shared specialist subagents who source and derive important shared knowledge from separate threads. It's useful because some skills just take too much of a token penalty to invoke and a single shared persistent session just lets that issue melt away. One agent pays the cost of that large skill once, and you don't have to keep paying for it in input tokens for the rest of that conversation.
- andai
I was reading about the HF hack and one of the first thing the GPT swarm did was build a messaging system for themselves. This reminded me of that. (Also of how weirded out I was by Moltbook when it came out. Time flies!)
Unrelated: when my Claude/Codex finishes cooking (or needs my attention), it pings a local HTTP endpoint that plays a frog sound on my laptop. I found this massively boosts quality of life.
- tizerluo
In fact, I don't understand what is this feature‘s difference between CMUX & Orca?
- Alifatisk
I wish there was a clean way to compact the conversation into a prompt with all necessary context for a new fresh conversation.
- singingtoday
I built something similar for my team. I can share context between my own sessions as well as theirs. It's especially useful when debugging problems, so my context can benefit from theirs and vice versa.