THE FULL SETUP GUIDE
Claude just started watermarking everything it writes. Here is the setup in under five minutes, then what the watermark actually is and why the usual tricks do not touch it.
The full setup walkthrough, first thing in the guide What the watermark really is (it is not hidden characters) Why the EU is the reason this is happening now The prompts that do the actual cleaning The mistakes that make people think it did not work What it can prove, and what nobody can prove yet A one page quick reference at the end
2026 Edition
On August 11 Anthropic announced that Claude is going to start watermarking the text it writes, and unlike most AI news this one affects you the moment you paste something into a doc. The reason it is happening now is the EU AI Act’s Transparency Code, which came into force on August 2 and pushes the big labs to make AI generated content identifiable.
Google already does this with Gemini, Anthropic is rolling it out now, and it is pretty safe to assume OpenAI and everyone else follows within the year. So this is not a Claude problem you can dodge by switching tools, it is where the whole industry is heading over the next twelve months.
The important thing to know before you start is that this is not the old invisible character trick where a zero width space gets slipped between your words. It is a completely different mechanic, which is why the advice you keep seeing in the comments does not work. There is a full explanation of how it works a few pages down, but the setup comes first because that is probably why you are here.
<aside> 💡
HEADS UP Pasting your text into Notepad and copying it back out does nothing to this watermark. Neither does saving it as a different file type, or retyping the same sentences by hand. Those all used to work on the older marks, which is why the advice is still going around, but the new one lives somewhere else entirely.
</aside>
A developer called Guillaume Meyer published a free open source Claude skill called watermarks-remover, and it went round fast because it was out within days of the announcement. The skill inside it is called remove-ai-marks. This takes about two minutes and it is all point and click.
STEP 1: Open the repo
Go to [github.com/guillaumemeyer/watermarks-remover](<https://github.com/guillaumemeyer/watermarks-remover>) in your browser.
STEP 2: Open the skills folder
In the file list near the top you will see a row labelled skills/remove-ai-marks. Click that.
STEP 3: Open SKILL.md
Inside you will see a file called SKILL.md. Click it to open it.
STEP 4: Download the raw file
In the top right of that file you will see Download raw file. Click it and the SKILL.md lands in your downloads.
STEP 5: Open your Claude skills
Go to Claude, click Customize, then Skills.
STEP 6: Upload it
Hit Add in the top right, choose Upload skill, then drag and drop the SKILL.md file straight in. That is the setup done.
TIP Turn on code execution while you are in there, under Settings then Capabilities. The skill uses it to do the cleaning, and if it is off you will get a refusal that looks like the skill is broken when it is just a setting.
WANT THE FULL VERSION TOO? The single file above gives you the text cleaning, which is what most people came for. If you also want the file tools, the ones that strip content credentials out of images and PDFs and audit a whole folder at once, grab the repo instead. Click the green Code button, then Download ZIP, unzip it, then zip up just the remove-ai-marks folder and upload that zip the same way. Same menu, same button.