OpenAI Agents SDK

An OpenAI Agents SDK agent runs on Rebuno unchanged apart from two seams. The OpenAI client under the model takes a Rebuno HTTP client, so every model call is recorded as an llm_call step, and tools are declared with @tool, so every tool call is recorded as a tool_call step. On a re-dispatch the agent runs from the top and recorded steps replay instead of calling the model or the tool again.

Install

pip install rebuno openai-agents

Model calls

Build the AsyncOpenAI client yourself with http_client(), and hand it to the model:

from agents import OpenAIResponsesModel
from openai import AsyncOpenAI
from rebuno import http_client

client = AsyncOpenAI(http_client=http_client())
model = OpenAIResponsesModel("gpt-5.5", client)

See LLM calls for the OpenAI SDK versions that accept the client.

Prompt cache key

Against api.openai.com, the Runner generates a random prompt_cache_key for each run. The key is part of the request body, so every model call would get a new step identity on resume and run again instead of replaying. Set the key to the execution id:

from agents import ModelSettings, RunConfig
from rebuno import execution

config = RunConfig(
    model_settings=ModelSettings(extra_args={"prompt_cache_key": str(execution().id)})
)

Tools

@tool keeps the function’s signature and docstring, so function_tool builds the tool schema from it as usual:

from agents import function_tool
from rebuno import tool


@tool("lookup_orders", idempotency="safe_to_retry")
async def lookup_orders(customer_id: str) -> dict:
    """Look up a customer's recent orders."""
    ...


@tool("send_email", idempotency="at_most_once")
async def send_email(body: str) -> dict:
    """Email the support summary."""
    ...


tools = [function_tool(fn, failure_error_function=None) for fn in [lookup_orders, send_email]]

By default function_tool turns a tool’s exception into an error message for the model. A tool held for approval raises to park the execution, so pass failure_error_function=None to let it unwind the run instead. A denied tool still returns the rule’s reason to the model, since a denial doesn’t raise. Mark anything with a side effect, such as sending an email or creating a ticket, at_most_once. See idempotency.

The agent

The SDK’s Agent and Rebuno’s Agent share a name, so import one under an alias:

from agents import Agent as OpenAIAgent
from agents import Runner
from rebuno import Agent


async def process(query: str) -> dict:
    client = AsyncOpenAI(http_client=http_client())
    specialist = OpenAIAgent(
        name="support specialist",
        model=OpenAIResponsesModel("gpt-5.5", client),
        tools=[function_tool(fn, failure_error_function=None) for fn in [lookup_orders, send_email]],
    )
    config = RunConfig(
        model_settings=ModelSettings(extra_args={"prompt_cache_key": str(execution().id)})
    )
    result = await Runner.run(specialist, query, run_config=config)
    return {"answer": result.final_output}


agent = Agent("support")

if __name__ == "__main__":
    agent.run(process)

What Rebuno adds

Policy. Every model and tool call is checked against policy before it runs. A denied tool returns the rule’s reason to the model as the tool result, so the agent can take a different path.
Approvals. A tool that requires approval parks the execution. Once it’s approved, the agent is dispatched again, the earlier steps replay, and the approved call runs.
Recovery. If the worker dies partway through, the next dispatch replays every completed step and continues from the first one that didn’t finish. Model calls that already ran are not paid for twice.

Full example

examples/frameworks/python/openai_agents_agent.py is a support agent that investigates a customer issue, creates a ticket, and emails a summary after approval.

Get started

Writing agents

Frameworks

Reference

OpenAI Agents SDK

Install

Model calls

Prompt cache key

Tools

The agent

What Rebuno adds

Full example

​Install

​Model calls

​Prompt cache key

​Tools

​The agent

​What Rebuno adds

​Full example

Install

Model calls

Prompt cache key

Tools

The agent

What Rebuno adds

Full example