How the target is found
The first argument can be any of these:
- a tmux id, like the value of
$OVERVIBE_SESSION - a session id
- an exact session name
- part of a name, where the most recently active match wins
Short names in the form project: role make partial matches safe. Two sessions both called "review" are an accident waiting to happen.
What the receiver sees
The text arrives with a header naming the sender, its tool and the exact command to answer with. Newlines are collapsed to spaces.
$ overvibe send "shop: codex copy" "Also shorten the CTA." # typed into the prompt of "shop: codex copy" [overvibe message from "shop: lead" (claude); reply with: overvibe send "shop: lead" "<reply>"] Also shorten the CTA.
Because the reply command is spelled out, an agent never has to guess the sender's name to answer.
Why a reply never arrives
Nearly always, the receiving agent is still in its turn: sleeping, polling, or waiting on a long command. The message sits in its prompt until the turn ends. Hand off, end the turn, and the reply comes in as a new message.
The other cause is a target outside Overvibe. A session in a plain Terminal tab has no pane to type into. Check with overvibe ls: the third column reads outside for those. Move it into Overvibe from the sidebar and it can receive.
Claude to Claude has a second option
Claude sessions can also message each other with Claude Code's own SendMessage. For Codex and agy, overvibe send is the only way in, so a brief that might go to any tool should use it.
Teach your agents once
overvibe --help prints the full usage with examples. One line in your CLAUDE.md or AGENTS.md pointing at it is enough for an agent to start using it, and the brief you give a helper should end with the exact overvibe send it must run when done.
Questions
Can I message a session from my own shell?
Yes. overvibe works from any shell on your Mac. From a plain shell the sender shows as you, and you can also stop any session.
Is there a length limit?
The message is typed into the prompt as one line, so keep long material in a file and send its path.
Does overvibe send work with deck?
deck is the old name of the same command and still works, and so does the short form ov.