LexiLint MCP — Spell & Grammar Checker for Claude Desktop & AI Assistants

What is the Model Context Protocol (MCP)?

The Model Context Protocol (MCP) is an open standard that allows AI assistants to connect to external tools and data sources. Think of it as a universal plugin system for AI.

Instead of the AI being limited to what it knows, MCP lets it:

• Read files from your filesystem
• Access databases and APIs
• Run specialized tools (like spell checkers!)
• Connect to any service you authorize

LexiLint MCP provides three tools to AI assistants:

1. spell_check — Check text for spelling errors (100% offline, free)
2. grammar_check — Check grammar with AI (BYOK, your API key)
3. check_text — Combined spell + grammar checking

Save Your AI Tokens for What Matters

Spell checking doesn't need AI. Stop paying for something a local dictionary can do instantly.

Save your tokens for complex grammar analysis where AI actually adds value. Let LexiLint handle the simple stuff for free.

Why Use LexiLint MCP?

Installation

Claude Desktop (Recommended)

Claude Desktop is Anthropic's official desktop app for Claude AI. It has built-in MCP support.

1. Open your Claude Desktop config file:

   • macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
   • Windows: %APPDATA%\Claude\claude_desktop_config.json

2. Add LexiLint to the mcpServers section:

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

3. Restart Claude Desktop

   Quit Claude completely (⌘Q on Mac) and reopen it.

4. Test it!

   In Claude Desktop, type: "Check this text for spelling: Thiss is a tesst"

   Claude will use LexiLint's spell_check tool and report the errors.

Other MCP Clients

LexiLint MCP works with any tool that supports the Model Context Protocol:

• Cursor IDE: Add to MCP settings
• Zed Editor: Configure in MCP servers
• Custom implementations: Run npx lexilint-mcp and connect via stdio

Usage Examples

Spell Check (Free, Offline)

Ask your AI assistant:

"Check this text for spelling errors: Thiss is a tesst with errrors"

The AI will use LexiLint's spell_check tool and return:

Found 3 spelling errors:

• "Thiss" at offset 0
  → suggestions: This, Hiss, Thins

• "tesst" at offset 11
  → suggestions: test, tests, Tess

• "errrors" at offset 22
  → suggestions: errors

Grammar Check (BYOK)

Configure your API key in settings (one-time setup). Then ask:

"Check this for grammar: This are incorrect grammar"

The AI will use LexiLint's grammar_check tool with your API key and return detailed grammar suggestions.

Combined Checking

"Proofread this entire paragraph for both spelling and grammar errors"

The AI can use the check_text tool to run both checks at once.

Free vs Premium

Premium: $29.99 lifetime or $2.99/month
Get Premium

Frequently Asked Questions

What is the Model Context Protocol (MCP)?

Model Context Protocol (MCP) is an open standard that allows AI assistants to connect to external tools and data sources. LexiLint's MCP server provides spell and grammar checking capabilities to Claude Desktop, ChatGPT, Cursor, and other MCP-compatible AI assistants.

How do I install LexiLint MCP in Claude Desktop?

Add LexiLint to your claude_desktop_config.json file with this configuration: {"mcpServers": {"lexilint": {"command": "npx", "args": ["lexilint-mcp"]}}}. The config file is located at ~/Library/Application Support/Claude/claude_desktop_config.json on macOS or %APPDATA%\Claude\claude_desktop_config.json on Windows.

Does LexiLint MCP work offline?

Yes! Spell checking is 100% offline — no API key needed, and your text never leaves your machine. Grammar checking uses your own API key (BYOK) and sends text directly to your chosen provider (Google Gemini, OpenAI, or Anthropic). Google Gemini has a free tier.

What AI assistants work with LexiLint MCP?

LexiLint MCP works with any AI assistant that supports the Model Context Protocol (MCP). This includes Claude Desktop (official Anthropic app), ChatGPT desktop with MCP plugin, Cursor IDE, Zed editor, and any other MCP-compatible tool.

Is LexiLint MCP free?

Yes! Spell checking (English US & UK) is 100% free and works offline. Grammar checking requires your own API key (BYOK) — Google Gemini offers a free tier. Premium features ($29.99 lifetime or $2.99/month) unlock 6 additional languages and multi-provider support (OpenAI, Anthropic).

What languages does LexiLint MCP support?

Free: English (US & UK). Premium: +6 languages (Spanish, French, German, Polish, Russian, Turkish). Both spell checking and grammar checking support all 8 languages.

Ready to Add Spell Checking to Your AI Workflow?

Install LexiLint MCP in under 2 minutes. Works with Claude Desktop, ChatGPT, Cursor, and more.

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