LexiLint

Spell and grammar checking for AI assistants via Model Context Protocol (MCP).

Works with Claude Desktop, Cursor, ChatGPT, and any MCP-compatible tool.

npm version MCP Registry

Features

• 🔒 100% offline spell check — uses nspell with local dictionaries. Zero tokens consumed. Zero API calls. Works without internet.
• 🤖 BYOK grammar check — bring your own Gemini (free tier), OpenAI, or Claude API key. Your text goes directly to your chosen provider.
• 💰 Zero token cost for spell check — stop wasting AI tokens on typo detection
• 🌍 8 languages — English (US/UK), Spanish, French, German, Polish, Russian, Turkish
• ⚡ Instant results — no latency, no rate limits, unlimited usage

Installation

Claude Desktop / Cursor / ChatGPT

Add to your MCP config:

{
  "mcpServers": {
    "lexilint": {
      "command": "npx",
      "args": ["-y", "lexilint-mcp"]
    }
  }
}

npm

npm install -g lexilint-mcp

Usage

Once installed, your AI assistant can use these tools:

• spell_check — check text for spelling errors (100% offline)
• grammar_check — check text for grammar issues (requires API key)

Example

"Use the spell_check tool to check this text: 'Ths is a tset'"

The spell check runs locally — no tokens consumed.

Token Cost Comparison

Method	Cost per 500-word check
Ask AI directly ("fix typos in this")	~$0.02 (GPT-4) / ~$0.015 (Claude)
LexiLint MCP spell_check	$0.00

Grammar Check Setup

Grammar checking uses your own API key (BYOK):

1. Get a free Google Gemini API key
2. Set the environment variable:

{
  "mcpServers": {
    "lexilint": {
      "command": "npx",
      "args": ["-y", "lexilint-mcp"],
      "env": {
        "GEMINI_API_KEY": "your-key-here"
      }
    }
  }
}

Supported providers: GEMINI_API_KEY, OPENAI_API_KEY, ANTHROPIC_API_KEY

Links

• 📦 npm package
• 🌐 Website & docs
• 🧩 Chrome Extension
• 📋 MCP Registry

License

MIT