The Decision In One Sentence
Pick OpenAI Agents SDK if official OpenAI primitives should define the framework layer. Pick Pydantic AI if typed Python structure and provider flexibility should define it instead.
Vendor Gravity Is The Whole Argument
This pair is not mainly about who has a longer feature list. It is about where you want architectural gravity to come from. OpenAI Agents SDK pulls the system toward OpenAI's tools, handoffs, sessions, and tracing model. Pydantic AI pulls it toward explicit Python structure, validation, and provider choice.
That is why the better choice often becomes obvious once you decide whether vendor alignment is a feature or a constraint.
When OpenAI Agents SDK Wins
- the stack is already strongly OpenAI-centered
- tools, handoffs, sessions, guardrails, and tracing should come from one official story
- faster alignment with OpenAI's framework model matters more than provider neutrality
- the team wants lower interpretive overhead around framework shape
When Pydantic AI Wins
- the team is Python-heavy and cares about typed application structure
- provider flexibility is a real requirement
- explicit validation and controllable app architecture matter more than official vendor alignment
- the framework should feel like part of the Python app, not just part of the model stack
The Better Prototype Question
Prototype the same agent boundary in both frameworks and ask a simple question: where does the architecture become easier to defend?
- In OpenAI Agents SDK, see how quickly the OpenAI-first workflow gets you moving.
- In Pydantic AI, see whether the typed application structure makes the system easier to own.
- Keep the version that better matches how your team wants to maintain the stack six weeks later.
What This Comparison Is Not About
This is not the cleanest framework comparison if the real problem is orchestration depth, long-running workflow control, or multi-agent architecture. For those questions, LangGraph and AutoGen are more relevant than either side of this pair.
Bottom Line
Choose OpenAI Agents SDK when official OpenAI workflow primitives are exactly what you want. Choose Pydantic AI when typed Python control and provider flexibility are more important than following one vendor's framework model.