Four JSON Schema Invariants for Reliable LLM Tags in CRM Workflows

The article argues that when an LLM's classification output triggers a CRM action, it should be governed by a JSON Schema rather than prompt-based text parsing. It proposes four invariants to check before accepting a result: a closed label vocabulary, correct value types, required fields, and explicit handling of uncertainty. Using a logistics sales call as the example, it shows a structured record with intent, urgency, follow-up flag, confidence, and supporting evidence. The author contends that a JSON parser alone only verifies decodability, while a schema defines legal values and mandatory fields. Schema validation does not guarantee correctness, but it makes malformed or out-of-contract outputs visible so they can be rejected or routed for review.