openai swarm is a lightweight reference framework from openai for routing between agent objects via handoffs, in-process, openai-only. bernstein orchestrates real cli coding agents (claude code, codex, aider, gemini, plus 33 more) in parallel git worktrees with a deterministic python coordinator and quality gates. swarm is great for prototyping multi-step llm tool-use against the openai api. bernstein is what you reach for once those agents need to actually write code, get lint+type+test gates, and merge to a real branch with an audit trail. matrix at https://bernstein.run/vs/openai-swarm.
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