THE OPENAI AGENTS SDK, EXPLAINED

The OpenAI Agents SDK is a deliberately minimal framework built around four ideas: agents, tools, handoffs and guardrails. Its design goal is to be small enough to read, which after a few years of increasingly baroque agent libraries is a real position rather than a lack of ambition.

The four concepts#

• Agent — instructions plus tools plus a model.
• Tool — a function the agent may call, typically with the schema derived from your type hints.
• Handoff — one agent delegating to another. This is the multi-agent story, and it is pleasingly simple: a handoff is just a particular kind of tool.
• Guardrail — a check that runs alongside, able to stop a run that has gone somewhere it should not.

Handoffs-as-tools is the neatest idea in the design. It means multi-agent coordination needs no new mental model — if you understand tool calling, you already understand delegation.

Why the small surface area matters#

Every abstraction a framework adds is one you must understand when something goes wrong at 2am. A framework you can read end to end in an afternoon is debuggable in a way a deep stack is not, and that advantage grows with the age of the codebase.

Built-in tracing matters for the same reason. As we argue in ADK vs Genkit, being able to see what happened is worth more in month two than any feature is in week one.

The obvious cost#

Coupling. This is a first-party SDK, and while it can be pointed at other providers, the design centre of gravity is one vendor's models and one vendor's hosted tooling. That is a reasonable trade if you have already made that choice — and an expensive surprise if you have not made it consciously.

The provider-neutral alternatives are Pydantic AI, which shares the taste for a small typed surface, and LangGraph, when the control flow itself needs to be explicit. The full map is in AI Agent Frameworks Compared.