max-union-properties

Category: Structural — overall schema structure triggers this rule

Error Codes

Profile	Code
anthropic.so.2026-04-30	ANT-S-max-union-properties

Description

Union parameters must not exceed 16

Rationale

anthropic.so.2026-04-30 limits parameters that use anyOf or type arrays across strict schemas.

Bad Example

{ "type": "object", "properties": { "value": { "anyOf": [{ "type": "string" }, { "type": "number" }] } } }

Good Example

{ "type": "object", "properties": { "value": { "type": "string" } }, "required": ["value"], "additionalProperties": false }