Co-Authored By Claude

A developer using Opus 5.5 reports an issue where the AI assistant consistently adds "Co-Authored-By: Claude" to commit messages, despite standing instructions against it. This behavior is new with Opus 5.5, as previous versions, including Opus 5, respected the rule. The developer notes that removing the line after a push would require rewriting the main branch, making it a significant inconvenience. They are inquiring if other users are experiencing the same problem.