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This example demonstrates how to use a non-reasoning model as a reasoning model. For reasoning, we recommend using a Reasoning Agent (with reasoning=True), or to use an appropriate reasoning model with reasoning_model=.

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Code

cookbook/reasoning/agents/default_chain_of_thought.py
from agno.agent import Agent
from agno.models.openai import OpenAIChat

reasoning_agent = Agent(
    model=OpenAIChat(id="gpt-5-mini"),
    reasoning_model=OpenAIChat(
        id="gpt-5-mini", # This model will be used for reasoning, although it is not a native reasoning model.
        max_tokens=1200,
    ),
    markdown=True,
)
reasoning_agent.print_response(
    "Give me steps to write a python script for fibonacci series",
    stream=True,
    show_full_reasoning=True,
)

# It uses the default model of the Agent
reasoning_agent = Agent(
    model=OpenAIChat(id="gpt-5-mini", max_tokens=1200),
    reasoning=True,
    markdown=True,
)
reasoning_agent.print_response(
    "Give me steps to write a python script for fibonacci series",
    stream=True,
    show_full_reasoning=True,
)

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Usage

1

Create a virtual environment

Open the Terminal and create a python virtual environment.
python3 -m venv .venv
source .venv/bin/activate
2

Set your API key

export OPENAI_API_KEY=xxx
3

Install libraries

pip install -U openai agno
4

Run Example

python cookbook/reasoning/agents/default_chain_of_thought.py