From the archive
OpenAI launches the Responses API and Agents SDK
The Responses API combines model replies with hosted tools, while the Agents SDK adds workflow orchestration and tracing.
OpenAI launched the Responses application programming interface (API) and Agents software development kit (SDK) on March 11, 2025. The release grouped model calls, hosted tools, and workflow tracing into a set of components for building assistants that perform multi-step tasks.
Tools in the API
Responses supported web search, file search, and computer use alongside model output. Web search supplied current information with source links, while file search retrieved material from uploaded documents. Computer use launched as a research preview for generating actions in a computer environment.
The API was available without a separate API access charge; model tokens and tool use were billed at their respective rates.
Coordinating an agent workflow
The Agents SDK provided orchestration for single-agent and multi-agent workflows. Integrated tracing made the sequence of model calls and actions inspectable. The release added a hosted-tool route for applications that previously had to assemble those integrations separately.