What's the difference between the OpenAI Agents SDK and AutoGen?

The OpenAI Agents SDK moves work by handoff: one agent delegates a task to another named agent, and that’s the whole exchange. Microsoft’s AutoGen signature pattern is a group chat instead, several agents reading the same thread while a manager decides who speaks next each round.

AutoGen rebuilt itself between v0.2 and v0.4 into what its own migration guide calls “an asynchronous, event-driven architecture.” The current AgentChat layer offers RoundRobinGroupChat and SelectorGroupChat for picking a next speaker, plus a Swarm preset that drops the central manager: each agent hands off by name through a tool call instead of a manager choosing, but every agent in a Swarm still reads and writes the same shared thread. The Agents SDK never runs a shared thread: a handoff hands the task and context to one named agent, and nothing else reads that exchange unless it’s handed off again.

Both patterns carry the same risk at the boundary: what looks fine in one agent’s own output can still be the failure, if the fact it needed never crossed to the next agent. A group chat just has more boundaries for that to happen at than a single handoff does.