Anthropic announced Tuesday that Claude embeds an invisible watermark in the text it generates. Any model released after August 2 does this automatically. Older models get it later. You can't turn it off. Here's how it actually works. The mark is invisible when you read it. It survives copy and paste. Anthropic says some of it survives editing. Files like images carry signed metadata showing Claude made them and whether they've been altered since. And it's applied at the model level, so it doesn't matter which door you came through. Claude, the API, Claude Code, Cowork, or Claude through AWS, Google Cloud, or Microsoft. Same mark. Worldwide, not just the EU. Anthropic is also building detection tooling and says it will publish how to check for it. Most of the internet spent this week being angry about it. That's the wrong reaction. Here's what to actually do. 1. Check what your contracts promise. If you have client agreements that say "original human written content," that language is now a real liability. Fix it before someone runs a detector, not after. 2. Disclose and move on. Say you use AI, say how, and say what you do on top of it. The operators who say it out loud are about to look a lot better than the ones who get found out. 3. Stop selling the writing. Sell the judgment. Nobody's paying you because you can type. They're paying for strategy, taste, and the fact that it works. None of that gets watermarked. 4. Learn to explain what detection actually proves. It's statistical, not a fingerprint. Anthropic says short or heavily edited text may not detect at all, and that no mark found does not mean it wasn't AI. You're going to need that sentence when a client waves a detector at you. 5. Assume this becomes standard. OpenAI signed the same EU code. Google is already on it. Building a workflow around dodging detection means rebuilding it every quarter forever. Two honest notes. Paraphrasing and heavy editing does dilute the mark, but treating that as your business model is a treadmill you don't get off. And Anthropic hasn't spelled out how any of this behaves on code specifically, so if that matters to what you deliver, wait for the technical details instead of guessing.