OpenClaw Regex Engine

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name: openclaw-regex-engine version: 2.0.0 description: "Production-grade regex processing suite — test patterns with capture groups, explain any regex in plain English, build regex from natural language descriptions, browse 50+ battle-tested patterns, and find-replace with backreferences. Use when: (1) user says 'test this regex' or 'does this pattern match', (2) user asks 'explain this regex' or 'what does this regex do', (3) user needs to 'build a regex for emails' or 'create a pattern that matches URLs', (4) user wants a 'ready-made regex for phone numbers' or 'UUID pattern', (5) user requests 'regex find and replace' or 'search and replace with backreferences'. Supports all ES2024 flags, named groups, lookahead/lookbehind. Zero install, sub-100ms on Cloudflare Workers. Free + Pro $9/mo." read_when: - "User pastes a regex pattern and wants to test it against sample text" - "User encounters a complex regex and asks what it does or how it works" - "User describes a matching goal in plain English and needs a regex built for them" - "User needs a common pattern for emails, URLs, IPs, UUIDs, phone numbers, or dates" - "User wants to perform regex-based find-and-replace with capture group references" commands: - regex_test - regex_explain - regex_build - regex_library - regex_replace metadata: openclaw: emoji: "\U0001F50D" homepage: https://github.com/yedanyagamiai-cmd/openclaw-mcp-servers always: false

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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 | regex_test | | 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.

:file_cabinet: 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.

:arrows_counterclockwise: SmartReplace Engine -- Full backreference support including named groups, global/first-match modes, and before/after diff preview.

MCP Quick Start

{
  "openclaw-regex": {
    "type": "streamable-http",
    "url": "https://regex-engine-mcp.yagami8095.workers.dev/mcp"
  }
}

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 | |-----------|------|---------|-------------| | pattern | string | required | Regex pattern to test | | text | 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: { matchCount, matches: [{ index, match, groups: [], namedGroups: {} }], executionTimeMs }

#### WRONG vs RIGHT

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

User: Does this regex match my test string?
Agent: *reads the regex visually, guesses "yes it should match"* — misses edge case with nested groups

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'"

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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 | |-----------|------|---------|-------------| | pattern | string | required | Regex pattern to explain | | flags | 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:

User: What does this regex do?
Agent: *guesses* "It matches passwords maybe?" — no detail on the lookaheads or minimum length

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"

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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 | |-----------|------|---------|-------------| | description | string | required | Plain English description of what to match | | options | object | {} | strict: boolean for anchored patterns, examples: string[] for guidance |

Output: { pattern, flags, explanation, testCases: { shouldMatch: [], shouldNotMatch: [] } }

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

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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 | |-----------|------|---------|-------------| | category | string | "" | Filter by category: email, url, ip, phone, date, uuid, jwt, credit_card, password, html, file_path, css | | search | 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.

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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 | |-----------|------|---------|-------------| | pattern | string | required | Regex pattern to find | | replacement | string | required | Replacement string with $1, $2, $ references | | text | string | required | Input text to transform | | flags | string | "g" | Regex flags |

Output: { result, replacementCount, diff: { before, after } }

Supports: $1-$9 numbered backreferences, $ 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 regex_build for complex parsers | NL-to-regex handles single patterns, not grammars | Build complex patterns manually with regex_explain` 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.