OpenAI’s Responses API is becoming an Agent API from Steven Heidel’s tweet:
Pretty interesting how OpenAI is moving up the stack where with an API call you can basically configure a tool calling ReAct agent. Over the last year, agent framework SDKs like LangGraph provide utilities to create react agents. Now with the Responses API, you can create this tool calling agent that can call remote MCP servers, code interpreter, RAG, image generation and we search tools natively.
Docs: https://openai.com/index/new-tools-and-features-in-the-responses-api/