Mason AI https://www.withmason.ai/ is an AI powered plan review software designed around how residential plan reviewers actually work. Reviewers start with their own markup pass, then compare it against Mason AI's checklist closing the gap between what a human caught and what the AI flagged. Mason AI checks full coverage of the CEC, CPC, Title 24 Energy Standards, CWUIC, CMC, CalGreen, and CRC (Architectural), while flagging local code amendments and local preferences for reviewer judgment; CRC Structural, the California Building Code, and solar permits fall outside its current scope.