@Override
    public List<ValidationEvent> validate(Model model) {
        List<ValidationEvent> events = new ArrayList<>();
        for (ServiceShape serviceShape : model.getServiceShapesWithTrait(EndpointRuleSetTrait.class)) {
            events.addAll(validateRuleSetBuiltIns(serviceShape,
                    serviceShape.expectTrait(EndpointRuleSetTrait.class)
                            .getEndpointRuleSet()));
        }

        for (ServiceShape serviceShape : model.getServiceShapesWithTrait(EndpointTestsTrait.class)) {
            events.addAll(validateTestTraitBuiltIns(serviceShape, serviceShape.expectTrait(EndpointTestsTrait.class)));
        }
        return events;
    }
Validates that the built-in's specified on parameters are supported.
smithy-rules-engine/src/main/java/software/amazon/smithy/rulesengine/validators/RuleSetBuiltInValidator.java