chatlas

Your friendly guide to building LLM chat apps in Python with less effort and more clarity.

Install

Install the latest stable release from PyPI:

pip install -U chatlas

Or, install the latest development version from GitHub:

pip install -U git+https://github.com/posit-dev/chatlas

Quick start

Get started in 3 simple steps:

1. Choose a model provider, such as ChatOpenAI or ChatAnthropic.
2. Visit the provider's reference page to get setup with necessary credentials.
3. Create the relevant Chat client and start chatting!

from chatlas import ChatOpenAI

# Optional (but recommended) model and system_prompt
chat = ChatOpenAI(
    model="gpt-4.1-mini",
    system_prompt="You are a helpful assistant.",
)

# Optional tool registration
def get_current_weather(lat: float, lng: float):
    "Get the current weather for a given location."
    return "sunny"

chat.register_tool(get_current_weather)

# Send user prompt to the model for a response.
chat.chat("How's the weather in San Francisco?")

Learn more at https://posit-dev.github.io/chatlas