Your agent calls get_weather(city="London") . The provider ships a new model version. Now it calls get_weather(location="London, UK") , your downstream parser breaks, and nothing in CI told you. I built a small library for exactly this failure: pip install toolcontract GitHub: https://github.com/Divyansh2202/toolcontract PyPI: https://pypi.org/project/toolcontract/ You pin a golden set of expected tool calls as a contract, re-run them against the live model, and get pass /...