OpenAI Agents SDK: Building Production AI Agents (2026)

The OpenAI Agents SDK (formerly Swarm, released as stable in early 2026) is a Python library for building multi-agent AI systems. Unlike LangChain's abstraction-heavy approach or CrewAI's role-playing model, the Agents SDK exposes five clean primitives and gets out of the way. This guide covers everything from setup to production deployment, including handoffs, guardrails, sessions, and tracing. Installing and Configuring pip install openai-agents Python 3.10+ required. Set your API key: export OPENAI_API_KEY = sk-... The SDK also works with non-OpenAI models via LiteLLM — more on that later. The Five Core Primitives Agent → LLM + system instructions + tools + handoffs Runner → executes the agent loop (sync or async) Tools → Python functions the agent can call Handoffs → transfer control to another agent Guardrails → validate input/output before processing Sessions → persistent conversation state Your First Agent from agents import Agent , Runner agent = Agent ( name = " Code Reviewer " , instructions = """ You are a senior Python developer reviewing code for correctness, security issues, and adherence to PEP 8. Be specific and actionable. """ ) result = Runner . run_sync ( agent , " Review this function: def add(a,b): return a+b " ) print ( result . final_output ) Runner.run_sync() is the blocking version. Use await Runner.run() in async contexts. Tools: Extending What Agents Can Do The @function_tool decorator converts any Python function into a tool the agent can call. The docstring becomes the tool's description — write it clearly: from agents import Agent , Runner , function_tool import subprocess import os @function_tool def run_tests ( test_path : str ) -> str : """ Run pytest on the specified test file or directory. Args: test_path: Relative path to test file or directory (must be within ./tests/) """ # Security: restrict to tests/ directory only safe_path = os . path . join ( " ./tests " , os . path . basename ( test_path )) if not os . path . exists ( safe