In the early days of AI tool-calling, we relied on a wing and a prayer. We gave an LLM a docstring and hoped it would guess the right types. If the Agent sent a string instead of a UUID, or a float instead of an integer, the system would crash, returning a generic 500 error that left the Agent stuck in an infinite retry loop. This is Parameter Hallucination , and it is the single biggest obstacle to building production-grade AI systems. At apcore , we solve this by making Strict Schema Enforcement a protocol-level requirement. In this twelfth article of our series, we dive into why data contracts are the only way to build a reliable Cognitive Interface. Why JSON Schema Draft 2020-12? When we designed apcore, we didn't want to invent a new schema language. We chose JSON Schema Draft 2020-12 . Why? Because it is the "Universal Vocabulary" of the modern web. It is language-agnostic, widely supported, and incredibly expressive.…