How to Add Humanizer from the Claude Plugin Marketplace: Complete Installation Guide

To add Humanizer from the Claude plugin marketplace, run /plugin marketplace add blader/humanizer followed by /plugin install humanizer@humanizer, then invoke the skill with /humanizer:humanizer to rewrite AI-generated text.

The Humanizer plugin, available in the blader/humanizer repository, transforms robotic AI prose into natural human writing. Distributed as a Claude plugin that resides in the /.claude-plugin directory, it exposes a skill defined in SKILL.md that registers the /humanizer command within Claude.

Prerequisites

Before installing Humanizer from the Claude plugin marketplace, ensure you are running Claude Code 2.1.142 or later (or any Claude client that supports the plugin protocol). The marketplace integration requires a client that can fetch and parse the marketplace.json manifest from the repository.

Step-by-Step Installation

Adding Humanizer requires two distinct commands: first registering the plugin source, then installing it into your active session.

Add the Plugin from the Marketplace

Open your Claude client and execute the marketplace add command:

/plugin marketplace add blader/humanizer

This command fetches the marketplace.json file from the blader/humanizer repository root and registers the plugin under the name humanizer within your local plugin registry.

Install the Plugin into Your Session

After adding the source, install the specific plugin instance using the @humanizer suffix selector:

/plugin install humanizer@humanizer

The @humanizer suffix tells Claude to load the plugin named humanizer defined in the marketplace manifest. At this stage, Claude reads the plugin.json manifest located in /.claude-plugin/plugin.json, which points to the skill folder ("./") and locates the SKILL.md file containing the rewrite instructions.

Verify the Installation

Once installed, confirm the plugin is active by invoking the skill:

/humanizer:humanizer

The double-colon syntax (/humanizer:humanizer) is the standard method for calling plugin-provided skills. Paste your AI-generated text immediately after the command to humanize it.

Plugin Architecture and Key Files

Understanding how Humanizer loads helps troubleshoot installation issues. The plugin uses a three-tier manifest system:

• SKILL.md — Located in the repository root, this file contains the actual skill prompt with 25 rewrite patterns and instructions. It is the only runtime code; Claude reads it directly when executing the command.

• /.claude-plugin/plugin.json — The plugin manifest that defines the entry point ("./"), version, author metadata, and skill location. This JSON file tells Claude where to find SKILL.md.

• /.claude-plugin/marketplace.json — The marketplace discovery manifest that exposes the plugin under the name humanizer. When you run /plugin marketplace add, Claude parses this file to identify the plugin source.

• agents/openai.yaml — A compatibility shim for OpenAI-compatible agents that references the same SKILL.md file, allowing the humanization logic to work across different AI platforms.

Using the Humanizer Skill

After installation, use the skill by typing the command followed by the text you want to rewrite:

/humanizer:humanizer

AI-generated text you want to humanize...

Claude processes the input through the patterns defined in SKILL.md and returns rewritten prose that mimics natural human writing patterns.

Alternative Installation via Skills CLI

If you prefer not to use the marketplace workflow, install the skill globally using the Skills CLI:

npx skills add blader/humanizer --global

This method bypasses the marketplace.json and plugin.json layers, installing SKILL.md directly as a global skill. After installation, invoke it with the simpler command:

/humanizer

Your AI-generated paragraph here...

Note that the CLI method uses /humanizer without the double-colon syntax, as it is registered as a native skill rather than a plugin-wrapped skill.

Summary

• To add Humanizer from the Claude plugin marketplace, run /plugin marketplace add blader/humanizer followed by /plugin install humanizer@humanizer.
• The core logic resides in SKILL.md at the repository root, which Claude reads directly at runtime.
• Manifest files in /.claude-plugin/ (plugin.json and marketplace.json) handle discovery and loading.
• Invoke the plugin using /humanizer:humanizer (double-colon syntax) when installed via the marketplace.
• Update the plugin by running the install command again; Claude fetches the latest SKILL.md automatically.

Frequently Asked Questions

What version of Claude Code is required to install the Humanizer plugin?

You need Claude Code version 2.1.142 or later, or any Claude client that supports the /plugin marketplace protocol. Earlier versions lack the marketplace API required to fetch marketplace.json from external repositories.

Can I use the Humanizer skill without installing it from the marketplace?

Yes. Use the Skills CLI command npx skills add blader/humanizer --global to install SKILL.md directly as a global skill. This bypasses the marketplace and plugin manifest layers, allowing you to call /humanizer without the @humanizer suffix or double-colon syntax.

Where is the actual humanization logic stored?

The logic is stored in SKILL.md at the repository root. This file contains 25 specific rewrite patterns and instructions that Claude follows to transform AI-generated text. The plugin.json and marketplace.json files only handle discovery and loading; they contain no rewrite logic.

How do I update the Humanizer plugin to the latest version?

Run the install command again: /plugin install humanizer@humanizer. Claude automatically fetches the latest SKILL.md from the blader/humanizer repository. Alternatively, if using the Skills CLI, run npx skills add blader/humanizer --global again to pull the latest version.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}