@aristeuroriz/mcp-katex-validator

MCP (Model Context Protocol) server that validates KaTeX / LaTeX expression syntax over stdio.

Use it from Cursor, VS Code (GitHub Copilot), Claude Desktop/Code, or any MCP client so agents can check math markup before rendering or saving it.

Features

• Single MCP tool: validate_katex
• Batch validation: pass one or many expressions in one call
• Strict KaTeX mode (throwOnError + strict: "error")
• Structured results with 0-based failure indexes
• Works via npx — no global install required

Requirements

• Node.js >= 20

Install

npm install -g @aristeuroriz/mcp-katex-validator

Or run without installing:

npx -y @aristeuroriz/mcp-katex-validator

MCP client setup

Add the server to your client's MCP config, then restart the client (or reload MCP servers).

Cursor

Paste into .cursor/mcp.json (project) or ~/.cursor/mcp.json (global):

{
  "mcpServers": {
    "mcp-katex-validator": {
      "command": "npx",
      "args": ["-y", "@aristeuroriz/mcp-katex-validator"]
    }
  }
}

Claude Desktop / Claude Code

Same mcpServers shape as Cursor (Claude Desktop config or project .mcp.json):

{
  "mcpServers": {
    "mcp-katex-validator": {
      "command": "npx",
      "args": ["-y", "@aristeuroriz/mcp-katex-validator"]
    }
  }
}

VS Code (GitHub Copilot)

Paste into .vscode/mcp.json:

{
  "servers": {
    "mcp-katex-validator": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@aristeuroriz/mcp-katex-validator"]
    }
  }
}

Tool: validate_katex

Validates one or more LaTeX strings with KaTeX in strict mode.

Input

| Field | Type | Required | Description | | --- | --- | --- | --- | | expressions | string[] | yes | One or more LaTeX formulas (minItems: 1) |

Example arguments:

{
  "expressions": ["E = mc^2", "\\frac{1}{", "\\sum_{i=1}^{n} i"]
}

Output

Returned as JSON text content and as structuredContent.

When every expression is valid:

{
  "allValid": true,
  "total": 2,
  "invalidCount": 0,
  "failures": []
}

When some fail, only failures are listed (0-based index):

{
  "allValid": false,
  "total": 3,
  "invalidCount": 1,
  "failures": [
    {
      "index": 1,
      "expression": "\\frac{1}{",
      "error": "Expected '}', got 'EOF' ..."
    }
  ]
}

If any expression is invalid, the MCP tool response sets isError: true.

Programmatic API

You can also import the validators in Node.js (without starting the MCP server):

import {
  validateKatex,
  validateKatexBatch,
} from "@aristeuroriz/mcp-katex-validator/validate";

validateKatex("E = mc^2");
// → { valid: true, expression: "E = mc^2" }

validateKatexBatch(["a^2", "\\frac{1}{"]);
// → { allValid: false, total: 2, invalidCount: 1, failures: [...] }

Zod schemas are available from @aristeuroriz/mcp-katex-validator/schemas.

Links

• npm package
• Source
• Issues
• Changelog

License

MIT © Aristeu Roriz Neto