Agent teams in this release is mcp-agent-mail [1] built into
  the runtime. Mailbox, task list, file locking — zero config,
  just works. I forked agent-mail [2], added heartbeat/presence
  tracking, had a PR upstream [3] when agent teams dropped. For
  coordinating Claude Code instances within a session, the
  built-in version wins on friction alone.

  Where it stops: agent teams is session-scoped. I run Claude
  Code during the day, hand off to Codex overnight, pick up in
  the morning. Different runtimes, async, persistent. Agent
  teams dies when you close the terminal — no cross-tool
  messaging, no file leases, no audit trail that outlives the
  session.

  What survives sherlocking is whatever crosses the runtime
  boundary. The built-in version will always win inside its own
  walls — less friction, zero setup. The cross-tool layer is
  where community tooling still has room. Until that gets
  absorbed too.

  [1] https://github.com/Dicklesworthstone/mcp_agent_mail
  [2] https://github.com/anupamchugh/mcp_agent_mail
  [3]
  https://github.com/Dicklesworthstone/mcp_agent_mail/pull/77