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:
- Choose a model provider, such as ChatOpenAI or ChatAnthropic.
- Visit the provider's reference page to get setup with necessary credentials.
- Create the relevant
Chat
client and start chatting!
from chatlas import ChatOpenAI
chat = ChatOpenAI(
model="gpt-4.1-mini",
system_prompt="You are a helpful assistant.",
)
def get_current_weather(lat: float, lng: float):
"Get the current weather for a given location."
return "sunny"
chat.register_tool(get_current_weather)
chat.chat("How's the weather in San Francisco?")
Learn more at https://posit-dev.github.io/chatlas