Rexact MCP

NPM MIT

A free MCP server that checks regexes from your AI assistant. It runs locally, offline, with no key or account.

Installation

Requirement: Node.js 20 or later.

claude mcp add rexact -- npx -y rexact-mcp

Add this block to the mcpServers configuration of your client:

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

verify_regex: tests a regex against cases.
check_redos: detects patterns with catastrophic backtracking.
explain_regex: explains a regex in plain language.
check_compat: checks compatibility across engines.
generate_regex: generates a regex from a description. This tool calls a model with your own Anthropic key, at your expense.

Privacy. No regex is sent to Rexact. Only generate_regex calls a model, with your key.