I Hate Watermarks
Paste AI-generated text, see the invisible characters hidden in it, and copy a clean version.
The cleaner runs entirely in the browser, so pasted text never leaves the page. The site is a
static export and uses Google Analytics to measure page visits.
It removes invisible-character watermarks: zero-width spaces and joiners, BOMs, soft hyphens,
bidi overrides, variation selectors, Unicode tag characters (which can spell out hidden
messages), private-use/noncharacter/reserved code points and exotic spaces. It keeps the
invisible characters real text needs (emoji ZWJ sequences, Persian/Indic joiners, flag tag
sequences, RTL marks).
It cannot remove statistical watermarks such as SynthID-Text, which live in word choice
rather than in any character.
Agent skill
skills/remove-ai-watermarks is an Agent Skill that gives coding
agents the same cleaner. Install it with the skills CLI, which supports
Claude Code, Codex, Cursor, Gemini CLI, GitHub Copilot and more:
npx skills add heyyarun/i-hate-watermarks
Or copy the folder by hand into ~/.claude/skills/ (Claude Code) or ~/.agents/skills/
(Codex). Then ask your agent something like "check essay.md for hidden AI watermark
characters and clean it". The skill runs scripts/watermarks.mjs, a single file with no
dependencies that needs Node.js 18 or newer:
node skills/remove-ai-watermarks/scripts/watermarks.mjs inspect essay.md
node skills/remove-ai-watermarks/scripts/watermarks.mjs clean -i essay.md
pbpaste | node skills/remove-ai-watermarks/scripts/watermarks.mjs clean | pbcopy
watermarks.mjs is generated from packages/skill and committed so the skill folder works
on its own. After changing packages/core or packages/skill, rebuild it with
corepack pnpm build:skill; a test fails if the committed file is out of date.
Layout
packages/core: the cleaning engine (TypeScript, no dependencies). Port of
watermarks-remover's Layer A engine.packages/skill: the skill's command-line front end, bundled into
skills/remove-ai-watermarks/scripts/watermarks.mjs.skills/remove-ai-watermarks: the installable skill (SKILL.md plus the bundled script).apps/web: the Next.js site (output: "export").
Develop
Uses pnpm through corepack (bundled with Node), so pnpm does not need to be on your PATH.
If it is, plain pnpm <script> works too.
corepack pnpm install
corepack pnpm dev # http://localhost:3000
corepack pnpm test # engine and skill tests, incl. parity with the Python original
corepack pnpm typecheck # works from a clean checkout; generates Next route types first
corepack pnpm build # static site in apps/web/out
corepack pnpm build:skill # skills/remove-ai-watermarks/scripts/watermarks.mjs
Regenerating data
Both scripts need uv. Fixtures also need a checkout of the reference repo.
cd packages/core
corepack pnpm gen:names # src/unicode-names.generated.ts
corepack pnpm gen:fixtures /path/to/watermarks-remover # test/fixtures/parity.json
License
MIT. See LICENSE and NOTICE.
