New tools and features in the Responses API

Source: OpenAI Date: 2025-05-21 URL: https://openai.com/index/new-tools-and-features-in-the-responses-api

Summary

OpenAI’s May 2025 update to the Responses API — adding new built-in tools (web search, file reading, code execution) and features (structured output improvements, streaming updates, conversation state management) to the API introduced in March 2025. The Responses API was OpenAI’s unified endpoint replacing the separate Chat Completions and Assistants APIs for agentic use cases.

Implications

API/agentic engineering thread. The Responses API is OpenAI’s central agentic infrastructure investment; each update extends its capability surface for agent builders. The May 2025 additions (built-in tools, state management) reduce the scaffolding developers need to build reliable agents — shifting complexity from application code to the API layer. This is how OpenAI competes with LangGraph, AutoGen, and similar frameworks: by absorbing agent orchestration primitives into the API itself. Watch which tools get built-in as a signal of what use cases OpenAI is prioritizing.