OpenAI Agents SDK

Metadata

• Author: Simon Willison’s Weblog
• Full Title: OpenAI Agents SDK
• URL: https://simonwillison.net/2025/Mar/11/openai-agents-sdk/#atom-everything

Highlights

• OpenAI Agents SDK. OpenAI’s other big announcement today (see also) - a Python library (openai-agents) for building “agents”, which is a replacement for their previous swarm research project. (View Highlight)
• In this project, an “agent” is a class that configures an LLM with a system prompt an access to specific tools. An interesting concept in this one is the concept of handoffs, where one agent can chose to hand execution over to a different system-prompt-plus-tools agent treating it almost like a tool itself. (View Highlight)
• The library also includes guardrails - classes you can add that attempt to filter user input to make sure it fits expected criteria. Bits of this look suspiciously like trying to solve AI security problems with more AI to me. (View Highlight)