humanizer for Claude Code and Codex: a skill that edits out machine-like prose

humanizer is a single skill that rewrites text that sounds machine-written so it reads like human writing, while keeping the meaning intact. This post covers the problem it solves, who it suits, how to install it and run it for the first time, and the one install detail that changes how you call it.

What problem it solves

Agent drafts tend to share the same tells: inflated claims, monotonous rhythm, and paragraphs that follow a template instead of the argument. Fixing them by hand means spotting each pattern, rewriting around it, and then checking that nothing true fell out along the way. humanizer turns that into a fixed sequence. It first flags 26 machine-like writing patterns, ordered by strength and frequency, then writes a new draft that preserves the meaning without being bound to the original structure, and finally checks for facts that were dropped or added before it produces the final version.

The pattern list is based on a Wikipedia article maintained by WikiProject AI Cleanup, grouped into six families. What keeps the skill safe for marketing copy is a rule about facts. Its instructions say to ask for missing names, numbers, dates, or quotes rather than fill them in. When you hand it a file path, it edits only prose and leaves code, data, frontmatter, and link URLs untouched.

Who it fits

The chapter rates four situations. Three are enough to decide.

Situation	Fit	Reason
Editing a launch announcement	Good fit	Checks exaggerated claims
Adjusting a newsletter’s voice	Good fit	Follows a writing sample
Adding examples that do not exist	Poor fit	Does not invent facts

Editing a manuscript file sits in the middle. It works, but the skill touches only prose, so structural changes are still yours to make.

Install and first run

Install it with the Skills CLI, as a Claude Code plugin, or globally for Codex.

# Install globally with Skills CLI
npx skills add blader/humanizer --global
# Install the Claude Code plugin
/plugin marketplace add blader/humanizer
/plugin install humanizer@humanizer
# Install globally for Codex
npx skills add blader/humanizer --global --agent codex

To run it, paste your text, make a request in plain language, or give it a file path and ask for an edit. The README says that two or three paragraphs of your own writing let it match your sentence length, word choices, and even habitual punctuation such as dashes.

[text to edit]
[a sample of my writing style]

When you paste text directly, it shows the first draft along with any problems that remain, then reads the text aloud to itself to catch passages that still sound machine-written.

What trips people up

The command you type depends on how you installed the skill. The plugin route requires Claude Code 2.1.142 or later, and once installed that way the invocation becomes /humanizer:humanizer rather than /humanizer. On an older Claude Code, install with the Skills CLI instead. Claude Desktop has no install command at all; you download the repository as a ZIP and upload it as a skill. Also keep in mind that the fact-checking step works best when you supply supporting material, since the skill asks for missing details rather than guessing them.

Where this comes from

This post adapts part of chapter 02-02 of The Claude Code & Codex Skills Guidebook. The full chapter covers how the six pattern groups and their before-and-after examples are organized, and a file-by-file look at what the repository ships, and the book has 52 more skills like this one. Read the full chapter in The Claude Code & Codex Skills Guidebook on Leanpub.