Code Review Checklist
shareAI-lab/learn-claude-code
Reviews code against a five-part checklist covering security, correctness, performance, maintainability and testing, and reports findings in a fixed format.
DEPRECATED: The base model generates, explains, and tests regex patterns natively with high accuracy.
MITAuto-check passed
Install Regex Builder
$ npx skills add Mathews-Tom/armory --skill regex-builder -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install Mathews-Tom/armory regex-builder --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/Mathews-Tom/armory.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/regex-builder .claude/skills/regex-builder && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "regex-builder" agent skill from https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builder into .claude/skills/regex-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "regex-builder", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builderType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add Mathews-Tom/armory --skill regex-builder -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install Mathews-Tom/armory regex-builder --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Mathews-Tom/armory.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/regex-builder .agents/skills/regex-builder && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "regex-builder" agent skill from https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builder into .agents/skills/regex-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "regex-builder", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add Mathews-Tom/armory --skill regex-builder -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install Mathews-Tom/armory regex-builder --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Mathews-Tom/armory.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/regex-builder .cursor/skills/regex-builder && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "regex-builder" agent skill from https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builder into .cursor/skills/regex-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "regex-builder", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/Mathews-Tom/armory.git --path skills/regex-builder--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add Mathews-Tom/armory --skill regex-builder -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install Mathews-Tom/armory regex-builder --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Mathews-Tom/armory.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/regex-builder .gemini/skills/regex-builder && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "regex-builder" agent skill from https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builder into .gemini/skills/regex-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "regex-builder", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install Mathews-Tom/armory regex-builderInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add Mathews-Tom/armory --skill regex-builder -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/Mathews-Tom/armory.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/regex-builder .github/skills/regex-builder && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "regex-builder" agent skill from https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builder into .github/skills/regex-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "regex-builder", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add Mathews-Tom/armory --skill regex-builder -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install Mathews-Tom/armory regex-builder --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Mathews-Tom/armory.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/regex-builder .opencode/skills/regex-builder && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "regex-builder" agent skill from https://github.com/Mathews-Tom/armory/tree/main/skills/regex-builder into .opencode/skills/regex-builder/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "regex-builder", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
regex-builder- GitHub stars
- 328
- Token cost
- ~2k tokens
- SKILL.md length
- 473 words
- Files
- 6 (incl. references)
- Skills in repo
- 80
- Repo updated
- First seen
- Licence
- MIT
At a glance
DEPRECATED: The base model generates, explains, and tests regex patterns natively with high accuracy.
- Works in 5 steps: Collect Examples → Infer Pattern → Explain Pattern → …
- SKILL.md covers Reference Files, Prerequisites, Workflow and Output Format
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Regex Builder is an agent skill from Mathews-Tom/armory. DEPRECATED: The base model generates, explains, and tests regex patterns natively with high accuracy. This skill no longer provides meaningful uplift. Retained for reference only.
Its SKILL.md is about 2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 7 other files, including reference files (for example `evals/cases.yaml`, `references/character-classes.md` and `references/common-patterns.md`).
It works with Python and JavaScript. The repository describes itself as: Curated, production-grade skills for AI coding agents. Battle-tested workflows for developers who use AI seriously. The licence is MIT.
Example prompts
- “/regex-builder”
Requirements
- Python 3
Workflow steps
5 steps, taken from the step headings in SKILL.md.
What it can do on your machine
Read from SKILL.md and the folder at commit 4594fb7. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are python and javascript).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Regex Builder loads about 2k tokens when it runs, and up to ~7k if it reads all its reference files. Until then it costs about 48 tokens; SKILL.md has 473 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from Mathews-Tom/armory at commit 4594fb7, republished under its MIT licence (© Mathews-Tom). 473 words, ~1,961 tokens.
Download SKILL.mdSave it as
.claude/skills/regex-builder/SKILL.md (or your agent's skills folder). This skill also uses 5 other files; get the full folder from GitHub.- name
- regex-builder
- description
- DEPRECATED: The base model generates, explains, and tests regex patterns natively with high accuracy. This skill no longer provides meaningful uplift. Retained for reference only.
- metadata.version
- 1.1.1
- metadata.status
- deprecated
- metadata.category
- development
- metadata.tags
- regex, pattern-matching, testing, validation
- metadata.difficulty
- beginner
DEPRECATED — Modern Claude models produce accurate, well-explained regex patterns with edge-case test suites natively, including multi-language usage examples. The uplift delta from this skill approaches zero. Retained for archival reference only.
Regex Builder
Transforms matching requirements (positive and negative examples) into tested regex patterns with component-by-component explanations, capture group documentation, edge case identification, and ready-to-use code in Python and JavaScript.
Reference Files
| File | Contents | Load When |
|---|---|---|
references/character-classes.md | Character class reference, Unicode categories, POSIX classes | Always |
references/quantifiers.md | Quantifier behavior, greedy vs lazy vs possessive, backtracking | Pattern needs repetition |
references/common-patterns.md | Validated patterns for email, URL, phone, IP, date, UUID, etc. | Common validation requested |
references/flavor-differences.md | Syntax differences between Python, JavaScript, PCRE, POSIX | Multi-language usage needed |
Prerequisites
- Clear specification: what should match and what should not
- Target regex flavor (Python
re, JavaScript, PCRE) — defaults to Python
Workflow
Phase 1: Collect Examples
Gather positive (should match) and negative (should not match) examples:
- From user — Explicit examples provided
- From context — If the user says "match email addresses," infer standard positive and negative examples
- From data — If sample data is provided, identify the pattern within it
Minimum: 3 positive examples and 3 negative examples. Fewer examples risk overfitting the pattern to specific cases.
Phase 2: Infer Pattern
Analyze the examples to build a pattern:
- Identify fixed literals — Characters that appear in the same position across all positive examples
- Identify character classes — Positions where different characters appear but follow a pattern (digits, letters, alphanumeric)
- Identify repetition — Elements that appear a variable number of times
- Identify optional elements — Parts present in some positive examples but not others
- Identify anchoring — Must the pattern match the entire string or can it be a substring?
Show full SKILL.md (192 more words)Show less
Phase 3: Explain Pattern
Break down the pattern into a component table:
| Component | Meaning |
|---|---|
^ | Start of string |
[A-Za-z] | One letter (upper or lower) |
\d{3,5} | 3 to 5 digits |
$ | End of string |
Document capture groups separately if the pattern uses them.
Phase 4: Generate Edge Cases
For every pattern, identify inputs that are likely to cause problems:
- Empty string — Does the pattern handle it correctly?
- Almost-matching strings — One character off from a valid match
- Boundary lengths — Minimum and maximum valid lengths
- Special characters — Dots, brackets, backslashes in the input
- Unicode — Multi-byte characters, emoji, diacritics
- Catastrophic backtracking — Inputs that cause exponential matching time
Phase 5: Output
Produce the pattern, explanation, test cases, and usage examples.
Output Format
## Regex Pattern: {Brief Description}
### Requirements
- **Must match:** {description of valid inputs}
- **Must reject:** {description of invalid inputs}
- **Flavor:** {Python re | JavaScript | PCRE}
### Pattern
```regex
{pattern}Explanation
| Component | Meaning |
|---|---|
{component} | {what it matches and why} |
Capture Groups
| Group | Name | Captures | Example |
|---|---|---|---|
| 1 | {name} | {what} | {example value} |
Test Cases
| # | Input | Should Match | Reason |
|---|---|---|---|
| 1 | {input} | Yes | {why — happy path} |
| 2 | {input} | Yes | {why — boundary} |
| 3 | {input} | No | {why — invalid} |
| 4 | {input} | No | {why — near-miss} |
| 5 | `` (empty) | No | Empty input |
Edge Cases
- {Edge case 1}: {what to watch for}
- {Edge case 2}: {what to watch for}
Usage
Python:
import re
pattern = re.compile(r'{pattern}')
# Match entire string
if pattern.fullmatch(text):
...
# Search within string
match = pattern.search(text)
if match:
captured = match.group(1)
# Find all matches
matches = pattern.findall(text)JavaScript:
const pattern = /{pattern}/;
// Test
if (pattern.test(text)) { ... }
// Match
const match = text.match(pattern);
if (match) {
const captured = match[1];
}
// Find all
const matches = [...text.matchAll(/{pattern}/g)];
## Calibration Rules
1. **Correctness over cleverness.** A readable, slightly longer pattern is better than
a cryptic short one. `[A-Za-z0-9]` is clearer than `\w` when you specifically mean
alphanumeric without underscores.
2. **Test negatives as rigorously as positives.** A pattern that matches everything
technically matches all positive examples. Negative examples prevent over-matching.
3. **Anchor when appropriate.** `^\d{3}$` matches exactly 3 digits. `\d{3}` matches
3 digits anywhere in the string. State the anchoring intent explicitly.
4. **Avoid catastrophic backtracking.** Nested quantifiers like `(a+)+` cause exponential
time on non-matching input. Test with adversarial inputs.
5. **Named groups over numbered groups.** `(?P<year>\d{4})` (Python) or `(?<year>\d{4})`
(JS) is self-documenting. Use numbered groups only for simple patterns.
6. **Specify the flavor.** Python `re`, JavaScript, and PCRE have different feature sets.
Lookaheads, lookbehinds, and Unicode support vary.
## Error Handling
| Problem | Resolution |
|---------|------------|
| Insufficient examples | Ask for more. Minimum 3 positive, 3 negative. |
| Contradictory examples | Flag the contradiction. Ask which examples are correct. |
| Requirements too complex for regex | Suggest a parser instead. Regex cannot handle recursive structures (nested brackets, HTML). |
| Pattern causes backtracking | Rewrite with atomic groups or possessive quantifiers. Test with worst-case input. |
| Unicode requirements unclear | Ask if the pattern needs to handle non-ASCII. Default to ASCII unless specified. |
| Multiple valid patterns | Present the simplest one. Mention alternatives if they have meaningful tradeoffs (performance vs readability). |
## When NOT to Build Regex
Push back if:
- The input requires parsing a recursive grammar (HTML, JSON, nested expressions) — use a parser
- The validation is for a standard format with a library (email validation, URL parsing) — use the standard library
- The pattern is for security-critical input validation as the sole defense — regex is a first filter, not a security boundary
- The user wants to modify matched content in complex ways — regex replacement has limits; suggest code instead© Mathews-Tom, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
SKILL.md and 5 other files (references) in skills/regex-builder of Mathews-Tom/armory.
- SKILL.md
- evals/cases.yaml
- references/character-classes.md
- references/common-patterns.md
- references/flavor-differences.md
- references/quantifiers.md
Open the folder on GitHubat commit 4594fb7
Compare with similar skills
Regex Builder next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Regex Builder this skillMathews-Tom/armory | 328 | — | ~2k | Automated safety check: Pass | MIT | |
| Code Review ChecklistshareAI-lab/learn-claude-code | 78k | 5 repos | ~1.1k | Automated safety check: Pass | MIT | |
| CCXT Crypto Exchange Library2025Emma/vibe-coding-cn | 23k | 2 repos | ~4.4k | Automated safety check: Pass | MIT | |
| Fory Releaseapache/fory | 4.6k | — | ~2.9k | Automated safety check: Pass | Apache-2.0 | |
| Gemini API Devgoogle-gemini/gemini-skills | 4.3k | — | ~5.1k | Automated safety check: Pass | Apache-2.0 | |
| jscpd Code Migration Trackerkucherenko/jscpd | 6.4k | — | ~5k | Automated safety check: Pass | MIT |
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Questions about Regex Builder
What does Regex Builder do?
DEPRECATED: The base model generates, explains, and tests regex patterns natively with high accuracy. Regex Builder is an agent skill from Mathews-Tom/armory. DEPRECATED: The base model generates, explains, and tests regex patterns natively with high accuracy.
How do I install Regex Builder in Claude Code?
Run `npx skills add Mathews-Tom/armory --skill regex-builder -a claude-code`. Or copy the skill folder (skills/regex-builder in Mathews-Tom/armory) into .claude/skills/regex-builder in your project. Claude Code loads it when a task matches its description.
How do I install Regex Builder in Codex?
Run `npx skills add Mathews-Tom/armory --skill regex-builder -a codex`. Or copy the skill folder (skills/regex-builder in Mathews-Tom/armory) into .agents/skills/regex-builder in your project. Codex loads it when a task matches its description.
Can I use Regex Builder in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add Mathews-Tom/armory --skill regex-builder -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/regex-builder, .gemini/skills/regex-builder, .github/skills/regex-builder and .opencode/skills/regex-builder in your project.
What does Regex Builder need to run?
SKILL.md names no scripts, command-line tools or credentials: Regex Builder is instructions for the agent only. Our summary lists: Python 3.
Does Regex Builder access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Regex Builder safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Regex Builder use?
Regex Builder is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Regex Builder use?
About 2k tokens (SKILL.md is roughly 7.8k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 5k tokens, read only when the agent opens those files.
What are the alternatives to Regex Builder?
Skills that share tags, products or a category with Regex Builder: Code Review Checklist (shareAI-lab/learn-claude-code, 78k stars), CCXT Crypto Exchange Library (2025Emma/vibe-coding-cn, 23k stars), Fory Release (apache/fory, 4.6k stars) and Gemini API Dev (google-gemini/gemini-skills, 4.3k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Regex Builder?
Mathews-Tom (a GitHub user) maintains it in Mathews-Tom/armory, which has 328 GitHub stars. The repository holds 80 skills in this directory. The repository was last updated on October 6, 2026.
Source: Mathews-Tom/armory on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.