What the SDK manages versus what we control

Up to this point, we have treated the OpenAI Agents SDK as a structured runtime for agents. This lesson exists to clarify an important boundary. When we use the SDK, some responsibilities move out of our code, while others remain firmly under our control. Understanding this division is essential for using the SDK effectively without losing architectural clarity.

Responsibilities handled by the SDK

The SDK takes ownership of several repetitive and coordination-heavy concerns that we previously implemented by hand. This includes managing interaction with the language model, maintaining conversational context, and orchestrating the back-and-forth between reasoning and tool use.

We no longer need to write custom loops to pass messages, track conversation turns, or repackage state for each model call. The SDK standardizes these behaviors and executes them consistently.

Responsibilities under developer control

Even with the SDK in place, we still decide what the agent is allowed to do and how it affects the outside world. We define tools, write their implementations, and determine how state is represented and persisted beyond what the SDK manages automatically.

We also remain responsible for validating inputs and outputs, enforcing safety boundaries, and deciding which parts of the system are deterministic versus model-driven. The SDK does not replace design judgment.

Configuration versus implementation decisions

Using the SDK introduces a clear distinction between configuration and implementation. Configuration answers questions like which model to use, how memory is handled, or which tools are available. Implementation answers questions like what a tool actually does or how a file is written.

This separation helps keep agent definitions concise while allowing complex behavior to live in ordinary Python code where it belongs.

Tradeoffs between abstraction and flexibility

The SDK’s abstractions reduce boilerplate, but they also hide some details. This is usually beneficial, but it means we accept certain defaults and conventions in exchange for speed and clarity.

When an application requires unusual control flow or highly customized behavior, those abstractions may feel restrictive. Recognizing this tradeoff helps us choose when to lean on the SDK and when to step outside it.

Conclusion

At this point, we are oriented around a key idea: the SDK manages coordination, context, and execution flow, while we manage behavior, rules, and consequences. With this boundary in mind, we can delegate confidently without surrendering control, and use the SDK as a tool rather than a black box.