Check out Claude Code Team Orchestration [1].

Set an env var and ask to create a team. If you're running in tmux it will take over the session and spawn multiple agents all coordinated through a "manager" agent. Recommend running it sandboxed with skip-dangerous-permissions otherwise it's endless approvals

Churns through tokens extremely quickly, so be mindful of your plan/budget.

1. https://code.claude.com/docs/en/agent-teams