OpenAI Agents SDK

The OpenAI Agents SDK is a lightweight yet powerful framework for building multi-agent workflows.

Core concepts:

1. Agents: LLMs configured with instructions, tools, guardrails, and handoffs
2. Handoffs: Allow agents to transfer control to other agents for specific tasks
3. Guardrails: Configurable safety checks for input and output validation
4. Tracing: Built-in tracking of agent runs, allowing you to view, debug and optimize your workflows

Explore the examples directory to see the SDK in action.

Get started

1. Set up your Python environment

python -m venv env
source env/bin/activate

2. Install Agents SDK

pip install openai-agents

Hello world example

from agents import Agent, Runner

agent = Agent(name="Assistant", instructions="You are a helpful assistant")

result = Runner.run_sync(agent, "Write a haiku about recursion in programming.")
print(result.final_output)

# Code within the code,
# Functions calling themselves,
# Infinite loop's dance.

(If running this, ensure you set the OPENAI_API_KEY environment variable)

Handoffs example

from agents import Agent, Runner
import asyncio

spanish_agent = Agent(
    name="Spanish agent",
    instructions="You only speak Spanish.",
)

english_agent = Agent(
    name="English agent",
    instructions="You only speak English",
)

triage_agent = Agent(
    name="Triage agent",
    instructions="Handoff to the appropriate agent based on the language of the request.",
    handoffs=[spanish_agent, english_agent],
)


async def main():
    result = await Runner.run(triage_agent, input="Hola, ¿cómo estás?")
    print(result.final_output)
    # ¡Hola! Estoy bien, gracias por preguntar. ¿Y tú, cómo estás?


if __name__ == "__main__":
    asyncio.run(main())

Functions example

import asyncio

from agents import Agent, Runner, function_tool


@function_tool
def get_weather(city: str) -> str:
    return f"The weather in {city} is sunny."


agent = Agent(
    name="Hello world",
    instructions="You are a helpful agent.",
    tools=[get_weather],
)


async def main():
    result = await Runner.run(agent, input="What's the weather in Tokyo?")
    print(result.final_output)
    # The weather in Tokyo is sunny.


if __name__ == "__main__":
    asyncio.run(main())

The agent loop

When you call Runner.run(), we run a loop until we get a final output.

1. We call the LLM, using the model and settings on the agent, and the message history.
2. The LLM returns a response, which may include tool calls.
3. If the response has a final output (see below for the more on this), we return it and end the loop.
4. If the response has a handoff, we set the agent to the new agent and go back to step 1.
5. We process the tool calls (if any) and append the tool responses messsages. Then we go to step 1.

There is a max_turns parameter that you can use to limit the number of times the loop executes.

Final output

Final output is the last thing the agent produces in the loop.

1. If you set an output_type on the agent, the final output is when the LLM returns something of that type. We use structured outputs for this.
2. If there's no output_type (i.e. plain text responses), then the first LLM response without any tool calls or handoffs is considered as the final output.

As a result, the mental model for the agent loop is:

1. If the current agent has an output_type, the loop runs until the agent produces structured output matching that type.
2. If the current agent does not have an output_type, the loop runs until the current agent produces a message without any tool calls/handoffs.

Common agent patterns

The Agents SDK is designed to be highly flexible, allowing you to model a wide range of LLM workflows including deterministic flows, iterative loops, and more. See examples in examples/agent_patterns.

Tracing

The Agents SDK includes built-in tracing, making it easy to track and debug the behavior of your agents. Tracing is extensible by design, supporting custom spans and a wide variety of external destinations, including Logfire, AgentOps, and Braintrust. See Tracing for more details.

Development (only needed if you need to edit the SDK/examples)

0. Ensure you have uv installed.

uv --version

1. Install dependencies

make sync

2. (After making changes) lint/test

make tests  # run tests
make mypy   # run typechecker
make lint   # run linter

Acknowledgements

We'd like to acknowledge the excellent work of the open-source community, especially:

• Pydantic (data validation) and PydanticAI (advanced agent framework)
• MkDocs
• Griffe
• uv and ruff

We're committed to continuing to build the Agents SDK as an open source framework so others in the community can expand on our approach.