JSON is a simple de facto standard cross-language textual format used to represent, exchange and store structured data in computer systems. Data schemas need to be described for documentation and verification purposes. Three JSON-based schema description languages have been proposed for JSON so far: JSON Schema, JSound and JSound-C. These languages are quite verbose and have a lax validation semantics: 60% of public schemas have been found defective [15] because JSON Schema is particularly error-prone. We introduce JSON Model, a work-in-progress alternative to previous proposals which is both lightweight and featureful, discuss key design choices and possible variants.