Claude Code (subscription) has Agent Teams built in. Teams of Agents communicate with local files that they use as inboxes and task list. Has tmux and iTerm 2 integration. https://code.claude.com/docs/en/agent-teams

They can rack up some extra tokens if you leave agents going idle. Because they loop, checking for new messages for them.

This fellow reverse-engineered exactly how it works and then abstracted the pattern into an MCP server that any Harness/agent can use. https://github.com/cs50victor/claude-code-teams-mcp

Have you seen https://www.roborev.io/ from Wes McKinney?

I put together a skill to do this with OpenCode and the GitHub Copilot provider. Works pretty well.

I’ve been keeping them open in tmux and using either send_keys or paste buffer for communication. Using print mode and always resume last means you can’t have parallel systems going.