agent-messaging-session-relaylisted

# Message another agent Deliver a message from this session to another running agent session, and verify the origin of messages that arrive here. Per-agent specifics live in an adapter — `references/codex.md` and `references/claude-code.md`. Read the one for the agent you are talking to; this file is the procedure. ## 1. Know your own address You cannot ask for a reply without one, and no transport supplies it for you. - **Codex**: `$CODEX_THREAD_ID`, injected into every command you run. - **Claude Code**: your session name, from `ListAgents`. Your inbox is `$CLAUDE_CODE_MESSAGING_SOCKET`. ## 2. Find the target Discovery is **vendor-scoped** — each agent enumerates only its own kind. To reach the other vendor you must read its registry directly. - **Claude sessions, from Claude**: `ListAgents`. Addresses are session names. - **Claude sessions, from anything else**: `claude agents --json` lists only live sessions, each with `name`, `pid`, and `status`. Read that session's inbox from `${CLAUDE_CONFIG_DIR:-$HOME/.claude}/sessions/<pid>.json`, field `messagingSocketPath` — never build the path yourself, because its directory follows `XDG_RUNTIME_DIR` and differs across hosts. Resolve a name through the listing, never by scanning the socket directory: it publishes no names, most entries are **stale**, and one logical session can hold two sockets (parent and child). - **Codex sessions, from anything**: all Codex state lives under `${CODEX_HOME:-$HOME/.codex}