Since the most part of this extension work is in the generate-code execution phase of the Quarkus Maven’s plugin, the log configuration must be set in the Maven context. When building your project, add -Dorg.slf4j.simpleLogger.log.org.openapitools=off to the mvn command to reduce the internal generator noise. For example:

mvn clean install -Dorg.slf4j.simpleLogger.log.org.openapitools=off

For more information, see the Maven Logging Configuration and Maven Configuration guides.