Claude now ships with a stamp on it. Since August 2, 2026, Anthropic has been invisibly marking the text of its newest models, with the older ones migrating over the following months.

No off switch. The backlash came fast: a wave of subscription cancellations, with cancellation screenshots making the rounds on X.

Before you cancel on reflex, it’s worth knowing what the mark actually is. It works quite differently from what most people picture, it exists for a concrete reason, and it vanishes with an almost comic ease.