Hiberius

Invisible Text Forensics — AI skill for Claude Code

AI community

Agent Skill that finds and removes invisible Unicode in text: zero-width characters, AI watermarks, bidi overrides (Trojan Source), tag-character prompt injection and homoglyphs.

How to install Invisible Text Forensics

This entry records only its repository, not the path inside it, so there is no exact command to give. Open Hiberius/invisible-text-forensics and copy the folder into ~/.claude/skills/, or the file into ~/.claude/agents/.

What Invisible Text Forensics does

Agent Skill that finds and removes invisible Unicode in text: zero-width characters, AI watermarks, bidi overrides (Trojan Source), tag-character prompt injection and homoglyphs. The byte layer every humanizer skill misses. Zero dependencies.

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README

Invisible Text Forensics

**An Agent Skill that reads text at the code point level: finds and removes zero-width characters, bidirectional overrides, tag characters, variation-selector payloads and homoglyphs. Also watermarks documents so you can tell which copy leaked.**

[![License: MIT](https://img.shields.io/badge/License-MIT-2ea44f.svg)](LICENSE) ![Python 3.8+](https://img.shields.io/badge/python-3.8%2B-3776AB?logo=python&logoColor=white) ![Zero dependencies](https://img.shields.io/badge/dependencies-0-6E56CF) ![Offline](https://img.shields.io/badge/network-never-8f9bb8)

npx skills add Hiberius/invisible-text-forensics

Works with Claude Code, Claude Desktop, Codex, Cursor, Windsurf, OpenClaw and anything else that reads a `SKILL.md`.

Why this exists

Humanizer and de-AI skills rewrite **style**: em dashes, "delve", tricolons. There are dozens of them and some have tens of thousands of stars. Not one of them reads the **bytes**.

Text carries characters that render as nothing and survive copy, paste, email, PDF extraction and git:

a zero-width watermark that says which copy of your contract this is
a run of tag characters spelling IGNORE PREVIOUS INSTRUCTIONS inside a prompt
a bidirectional override making source code render differently from how it compiles
a no-break space in a CSV header that quietly breaks a column lookup

This skill is the layer underneath the humanizers. Run a humanizer for the prose, run this for everything the prose is made of.

Try it in ten seconds

python3 scripts/itf.py scan document.md

document.md
  CRITICAL U+202E     line 12 col 18  Right-to-Left Override (RLO)
           reorders rendering; Trojan Source (CVE-2021-42574) in source code
  HIGH     U+200B     line 3 col 41   Zero Width Space (ZWSP)
           invisible; carries watermarks and hidden payloads
  MEDIUM   U+0443     line 3 col 58   Homoglyph of 'y'
           non-Latin letter that renders like ASCII