Summary
Adds five regex and text processing tools directly to Claude: test patterns with match indices and capture groups, replace with backreferences, extract matches as structured arrays, and get human-readable explanations of regex syntax. The text_transform tool handles case conversions (camelCase, snake_case, PascalCase, kebab-case), line operations (deduplicate, sort, remove blanks), and basic transformations like trim and reverse, with support for chaining multiple operations. Useful when you're parsing logs, cleaning data, or prototyping text manipulation without switching contexts to a regex tester or writing throwaway scripts. Runs locally via Node.js with stdio transport.
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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
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
{
"mcpServers": {
"regex-tools": {
"command": "node",
"args": ["D:/products/mcp-servers/mcp-regex-tools/dist/index.js"]
}
}
}
Usage with Claude Code
claude mcp add regex-tools node D:/products/mcp-servers/mcp-regex-tools/dist/index.js
Or add to your .mcp.json:
{
"mcpServers": {
"regex-tools": {
"command": "node",
"args": ["D:/products/mcp-servers/mcp-regex-tools/dist/index.js"]
}
}
}
Examples
Test a regex
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
regex_replace({ pattern: "(\\w+)\\s(\\w+)", replacement: "$2 $1", text: "hello world" })
Extract matches
regex_extract({ pattern: "[\\w.]+@[\\w.]+", text: "Contact us at info@example.com or support@example.com" })
Explain a regex
regex_explain({ pattern: "^(?:https?://)?(?:www\\.)?([\\w-]+)\\.\\w{2,}$", flags: "i" })
Transform text
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
Featured
Plug Mailtrap into your AI workflow and let it handle the email.
Connect Mailtrap MCP →Agent, run crypto. Access onchain data & trade routes via 1inch.
Install now →Make coding agent sessions - Searchable, Shareable, Vendor-neutral & Scored.
Try For Free →Your agent targets a perfect 10 Code Health score. Deterministic. Every commit.
Try For Free →Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →belt cli automatically finds the best tools and skills for your agent. image, video, music, tts...
one prompt install →