io.github.rog0x/regex

Official

by rog0x · TypeScript

Regex test, explain, replace patterns for AI agents

Tests, explains, and applies regular expression patterns.

Topics

ai-agentsclaudemcpmodel-context-protocolregextext-processingtypescriptai-toolsdeveloper-toolsmcp-server

README.md2 KBView on GitHub

mcp-regex-tools

Regex and text processing tools for AI agents via the Model Context Protocol (MCP).

Tools

Tool	Description
`regex_test`	Test a regex pattern against text. Returns all matches with indices, captured groups, and named groups.
`regex_replace`	Find and replace using regex with support for capture group references (`$1`, `$2`, `$&`, `$<name>`).
`regex_extract`	Extract all matches of a pattern from text as a structured array. Optionally return only a specific capture group.
`regex_explain`	Parse a regex pattern and return a human-readable explanation of each component and flag.
`text_transform`	Apply common text transformations: camelCase, snake_case, kebab-case, PascalCase, UPPER, lower, title case, reverse, trim, deduplicate lines, sort lines, remove blank lines, count words/chars/lines. Chain multiple transforms in one call.

Setup

bash

npm install
npm run build

Usage with Claude Desktop

Add this to your Claude Desktop config file:

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

json

{
  "mcpServers": {
    "regex-tools": {
      "command": "node",
      "args": ["D:/products/mcp-servers/mcp-regex-tools/dist/index.js"]
    }
  }
}

Usage with Claude Code

bash

claude mcp add regex-tools node D:/products/mcp-servers/mcp-regex-tools/dist/index.js

Or add to your .mcp.json:

json

{
  "mcpServers": {
    "regex-tools": {
      "command": "node",
      "args": ["D:/products/mcp-servers/mcp-regex-tools/dist/index.js"]
    }
  }
}

Examples

Test a regex

code

regex_test({ pattern: "(\\d{4})-(\\d{2})-(\\d{2})", text: "Today is 2026-03-19 and tomorrow is 2026-03-20" })

Replace with capture groups

code

regex_replace({ pattern: "(\\w+)\\s(\\w+)", replacement: "$2 $1", text: "hello world" })

Extract matches

code

regex_extract({ pattern: "[\\w.]+@[\\w.]+", text: "Contact us at info@example.com or support@example.com" })

Explain a regex

code

regex_explain({ pattern: "^(?:https?://)?(?:www\\.)?([\\w-]+)\\.\\w{2,}$", flags: "i" })

Transform text

code

text_transform({ text: "hello world example", transforms: ["PascalCase"] })
text_transform({ text: "some text\nwith\nlines\nwith\nduplicates\nlines", transforms: ["deduplicate_lines", "sort_lines"] })

License

MIT

Install

claude_desktop_config.json

{
  "mcpServers": {
    "regex": {
      "command": "npx",
      "args": [
        "-y",
        "@rog0x/mcp-regex-tools@1.0.1"
      ]
    }
  }
}