OpenClaw Regex Engine v2.0

Master regular expressions -- 5 tools to test, explain, build, browse, and replace patterns instantly.

Quick Reference

Situation	Action	Tool
Have a regex, need to test it	Run against text, get all matches + groups	INLINECODE0
Found a scary regex in legacy code

Get plain-English breakdown of every token | regex_explain | | Know WHAT to match but not HOW | Describe in English, get production regex | regex_build | | Need a standard pattern (email, URL, IP) | Browse 50+ battle-tested patterns | regex_library | | Need to transform text with regex | Find-replace with backreferences ($1, $2) | regex_replace | | Complex pattern with capture groups | Test + Explain combo for full understanding | regex_test + regex_explain |

What's New in v2.0

• - :brain: PatternForge Builder -- Describe what you want in plain English. Get a production-ready regex with positive/negative test cases, flags, and explanation included.
• :book: RegexLens Explainer -- Break any regex into human-readable components token-by-token. Even nested lookaheads, possessive quantifiers, and Unicode categories.
• :filecabinet: BattleTest Library -- 50+ curated patterns for email, URL, phone (international), IPv4/IPv6, UUID, JWT, credit card, date formats, file paths, and more. Every pattern includes test cases.
• :arrowscounterclockwise: SmartReplace Engine -- Full backreference support including named groups, global/first-match modes, and before/after diff preview.

MCP Quick Start

CODEBLOCK0

Add to Claude Desktop, Cursor, Windsurf, VS Code, or any MCP-compatible client. No API key needed for Free tier. Works immediately.

Detection Triggers

This skill activates when you say:

• - "test this regex" / "does this pattern match" / "run this regex against"
• "explain this regex" / "what does this regex do" / "break down this pattern"
• "build a regex for" / "create a pattern that matches" / "regex for emails"
• "regex for URL" / "phone number regex" / "UUID pattern" / "IP address regex"
• "regex replace" / "find and replace with regex" / "search and replace with capture groups"
• "regular expression" / "pattern matching" / "capture groups" / "backreference"

Tools (5)

regex_test -- Match & Capture (PatternMatch Protocol)

Test a regex pattern against input text. Returns every match with full capture group detail, named groups, and exact index positions.

Parameter	Type	Default	Description
INLINECODE8	string	required	Regex pattern to test
INLINECODE9

string | required | Input text to match against |
| flags | string | "g" | Flags: g global, i case-insensitive, m multiline, s dotall, u unicode, v unicodeSets |

Output: INLINECODE17

WRONG vs RIGHT

WRONG -- Manually scanning text to check if a pattern works:
CODEBLOCK1

RIGHT -- Use regex_test:

User: Does this regex match my test string?
Agent: calls regex_test → "3 matches found. Match 1 at index 15: 'user@example.com', group 1: 'user', group 2: 'example.com'"

---

regex_explain -- Human-Readable Breakdown (RegexLens)

Break any regex into plain English, token by token. Each component gets a description, what it matches, and example matches.

Parameter	Type	Default	Description
INLINECODE20	string	required	Regex pattern to explain
INLINECODE21

string | "" | Active flags to include in explanation |

Handles: Character classes, quantifiers, anchors, groups (capturing, non-capturing, named), lookahead/lookbehind (positive and negative), backreferences, Unicode categories, and alternation.

Output: Array of { token, type, description, matches_example } plus overall summary.

WRONG vs RIGHT

WRONG -- Staring at ^(?=.*[A-Z])(?=.*[0-9])(?=.*[!@#$%])[A-Za-z0-9!@#$%]{8,}$ and guessing:
CODEBLOCK3

RIGHT -- Use regex_explain:

User: What does this regex do?
Agent: calls regex_explain → "Password validator: requires at least 1 uppercase letter (lookahead 1), 1 digit (lookahead 2), 1 special char from !@#$% (lookahead 3), minimum 8 characters total from allowed set"

---

regex_build -- Natural Language to Regex (PatternForge)

Describe what you want to match in plain English. Get a production-ready regex with recommended flags, explanation, and test cases (both positive and negative).

Parameter	Type	Default	Description
INLINECODE26	string	required	Plain English description of what to match
INLINECODE27

object | {} | strict: boolean for anchored patterns, examples: string[] for guidance |

Output: INLINECODE30

Example: Input "match email addresses" produces a complete RFC-5322-lite pattern with 5 positive and 5 negative test cases.

---

regex_library -- Pattern Collection (BattleTest Library)

Browse 50+ curated, production-tested regex patterns organized by category. Every pattern includes the regex string, description, recommended flags, and positive/negative test cases.

Parameter	Type	Default	Description
INLINECODE32	string	""	Filter by category: email, url, ip, phone, date, uuid, jwt, credit_card, password, html, file_path, INLINECODE44
INLINECODE45

string | "" | Free-text search across pattern names and descriptions |

Categories: email, URL, IPv4, IPv6, phone (US, UK, JP, international), date (ISO, US, EU), UUID (v1-v5), JWT, credit card (Visa, MC, Amex), password strength, HTML tags, file paths (Unix, Windows), CSS selectors, color codes, semantic versioning.

---

regex_replace -- Find & Replace (SmartReplace Engine)

Perform regex-based find-and-replace with full capture group reference support ($1, $2, named groups), global and first-match modes.

Parameter	Type	Default	Description
INLINECODE47	string	required	Regex pattern to find
INLINECODE48

string | required | Replacement string with $1, $2, $<name> references |
| text | string | required | Input text to transform |
| flags | string | "g" | Regex flags |

Output: INLINECODE54

Supports: $1-$9 numbered backreferences, $<name> named backreferences, $& full match, ` $ ` pre-match, $' post-match. ## What NOT to Do | Don't | Why | Do Instead | |-------|-----|------------| | Use catastrophic backtracking patterns like (a+)+$ | Will timeout on edge workers (~50ms limit) | Rewrite with atomic groups or possessive quantifiers | | Expect PCRE-only features (conditional patterns, recursion) | Uses JavaScript ES2024 regex engine | Stick to JS-compatible syntax | | Send input text over 100KB | Memory limits on edge workers | Split large texts into chunks | | Rely on patterns for security validation alone | Regex is for format checking, not sanitization | Combine with server-side validation | | Use regexbuild for complex parsers | NL-to-regex handles single patterns, not grammars | Build complex patterns manually with regexexplain` to verify |

Security & Privacy

What	Status
Reads your input text and patterns	Yes -- for processing only
Stores your data

No -- zero persistence, stateless edge processing | | Sends data to third parties | No -- processed entirely on Cloudflare Workers | | Logs request content | No -- only anonymous usage counters | | Executes patterns server-side | Yes -- sandboxed with 50ms timeout to prevent ReDoS | | Requires authentication | Free tier: no. Pro: API key header only |

Pricing

Tier	Calls/Day	Price	What You Get
Free	20	$0	All 5 regex tools, no signup
Pro

1,000 | $9/mo | All 9 OpenClaw servers (49 tools), priority routing | | x402 | Pay-per-call | $0.05 USDC | No account needed, crypto-native |

Get Pro Key: https://buy.stripe.com/4gw5na5U19SP9TW288

The OpenClaw Intelligence Stack

Server	Tools	Best For
JSON Toolkit	6	Format, validate, diff, query, transform JSON
Regex Engine

5 | Test, extract, replace, explain regex patterns | | Color Palette | 5 | Generate, convert, harmonize, accessibility-check colors | | Timestamp Converter | 5 | Parse, format, diff, timezone-convert timestamps | | Prompt Enhancer | 6 | Optimize, rewrite, score, A/B test AI prompts | | Market Intelligence | 6 | AI market trends, GitHub stats, competitor analysis | | Fortune & Tarot | 3 | Daily fortune, tarot readings, I Ching | | Content Publisher | 8 | MoltBook posts, social content, newsletter | | AgentForge Compare | 5 | Compare AI tools, frameworks, MCP servers |

All 9 servers share one Pro key. $9/mo = 49 tools.