Rephrasy MCP Server

Use Rephrasy from Claude, Cursor, or any MCP client: humanize AI-generated text and check AI-detection scores without leaving your editor or agent workflow.

Two tools, one API key:

| Tool | What it does | |---|---| | humanize | Rewrites AI-generated text in a natural, human style while preserving meaning | | detect | Scores how likely a text is to be flagged as AI-written (overall + optional per-sentence) |

Setup

1. Get an API key — sign in at rephrasy.ai → Account → API. Both tools bill against your Rephrasy plan.

2. Add the server to your client:

Claude Code

claude mcp add rephrasy -e REPHRASY_API_KEY=<your-key> -- npx -y @rephrasy/mcp

Claude Desktop

Add to claude_desktop_config.json (Settings → Developer → Edit Config):

{
  "mcpServers": {
    "rephrasy": {
      "command": "npx",
      "args": ["-y", "@rephrasy/mcp"],
      "env": { "REPHRASY_API_KEY": "<your-key>" }
    }
  }
}

Cursor

Add to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "rephrasy": {
      "command": "npx",
      "args": ["-y", "@rephrasy/mcp"],
      "env": { "REPHRASY_API_KEY": "<your-key>" }
    }
  }
}

Until the package is on npm you can run it straight from GitHub: replace "args": ["-y", "@rephrasy/mcp"] with "args": ["-y", "github:rephrasyai/rephrasy-mcp"].

Hosted server (no install)

Rephrasy also runs a hosted MCP server, so clients that speak streamable HTTP need nothing installed locally:

claude mcp add rephrasy https://v2-humanizer.rephrasy.ai/mcp -t http \
  -H "Authorization: Bearer <your-key>"

It supports OAuth as well — ChatGPT and other clients that require it discover it from the server and send you through a one-time consent page, so the key never reaches the client. The hosted server carries a wider tool set (engine recommendations, readability, bring-your-own-key detectors). Full docs: https://rephrasy.ai/mcp.

Tools

humanize

| Parameter | Type | Required | Description | |---|---|---|---| | text | string | yes | The text to humanize | | model | string | no | Rephrasy model, default "v4" (recommended). See Models | | style | string | no | Writing-style ID from your account to mimic a specific voice | | language | string | no | Output language hint (e.g. "en", "de"); defaults to input language |

Returns the rewritten text plus the number of words charged.

Models

| model | When to use it | |---|---| | v4 | Default and recommended. Natural rhythm and sentence variety, length close to the source. | | ft_clean-v3 | Highest meaning retention and near-identical length — technical writing and anything with figures. | | v3 | Voice-driven rewrite; pass style for a specific voice. | | SEO Model | Simple, informal phrasing built around keywords. | | Undetectable Model v2 | Previous-generation model. |

detect

| Parameter | Type | Required | Description | |---|---|---|---| | text | string | yes | The text to score (max 15,000 characters) | | per_sentence | boolean | no | If true, also returns a score per sentence |

Returns JSON with scores.overall (lower = more human-like) and, in per-sentence mode, sentences.

Example prompts

• "Humanize this paragraph, then run detect on the result to verify it."
• "Rewrite my draft with the humanize tool using my writing style <style-id>."
• "Check which sentences of this post read as AI-written."

Development

npm install
npm run build
REPHRASY_API_KEY=<key> node dist/index.js   # runs on stdio

License

MIT © Rephrasy