The Model Didn't Change. A Parameter Disappeared. Thousands of Pipelines Broke.

An LLM vendor dropped two sampling parameters this month. Every hard-coded call that passed them started throwing errors. The model was fine. The weights were fine. The contract changed — and thousands of pipelines discovered they never had one. Here's the uncomfortable symmetry. You pin your packages. You contract-test your APIs. You'd never let a payment provider change a request schema under you without a canary catching it. But the LLM call — the one sitting in the middle of your most…