LangGraph calculator quickstart

A Graph API implementation of the official LangGraph calculator quickstart. It exposes add, multiply, and divide as tools and loops between an LLM node and a tool node until the model returns a final answer.

Setup

cd /home/plamaimu/Projects/cal/langgraph-calculator
cp .env.example .env
# Edit .env and set KIMI_API_KEY.
uv sync --all-groups
uv run python calculator.py "Add 3 and 4."

The calculator calls Kimi's OpenAI-compatible endpoint https://api.moonshot.ai/v1 through ChatOpenAI. CALCULATOR_MODEL defaults to kimi-k3; set KIMI_API_KEY in .env before invoking the live model.

Test without a provider key

uv run pytest

Sources

• https://docs.langchain.com/oss/python/langgraph/quickstart
• https://docs.langchain.com/oss/python/langgraph/overview