luongnv89/claude-howto is a visual, example-based guide to Claude Code, a coding tool that supports agents, hooks, skills, slash commands, and MCP servers. Developers use it to learn Claude Code through practical workflows and copyable templates, including the commands, agents, skills, plugins, and instructions catalogued here.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/luongnv89/claude-howto/refactornpx skills add luongnv89/claude-howto --skill refactorgit clone --depth 1 https://github.com/luongnv89/claude-howtoWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/luongnv89/claude-howto/refactor)<a href="https://agentmods.dev/skills/luongnv89/claude-howto/refactor"><img src="https://agentmods.dev/badge/skills/luongnv89/claude-howto/refactor.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00064 | $0.02789 |
| Opus 5 | $0.00032 | $0.01394 |
| Sonnet 5 | $0.00013 | $0.00558 |
| Haiku 4.5 | $0.00006 | $0.00279 |
Grade A, and why
refactor scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
1 near-identical copy found in the catalogue:
- code-refactor — 95% identical, 10 lines differ
How it starts
The opening of the file, as written. The whole thing — 435 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Code Refactoring Skill
A systematic approach to refactoring code based on Martin Fowler's Refactoring: Improving the Design of Existing Code (2nd Edition). This skill emphasizes safe, incremental changes backed by tests.
"Refactoring is the process of changing a software system in such a way that it does not alter the external behavior of the code yet improves its internal structure." — Martin Fowler
Core Principles
- Behavior Preservation: External behavior must remain unchanged
- Small Steps: Make tiny, testable changes
- Test-Driven: Tests are the safety net
- Continuous: Refactoring is ongoing, not a one-time event
- Collaborative: User approval required at each phase
Workflow Overview
Phase 1: Research & Analysis
↓
Phase 2: Test Coverage Assessment
↓
Phase 3: Code Smell Identification
↓
Phase 4: Refactoring Plan Creation
↓
Phase 5: Incremental Implementation
↓
Phase 6: Review & Iteration
Phase 1: Research & Analysis
Objectives
- Understand the codebase structure and purpose
- Identify the scope of refactoring
- Gather context about business requirements
Questions to Ask User
Before starting, clarify:
- Scope: Which files/modules/functions need refactoring?
- Goals: What problems are you trying to solve? (readability, performance, maintainability)
- Constraints: Are there any areas that should NOT be changed?
- Timeline pressure: Is this blocking other work?
- Test status: Do tests exist? Are they passing?
Actions
- Read and understand the target code
- Identify dependencies and integrations
- Document current architecture
- Note any existing technical debt markers (TODOs, FIXMEs)
Output
Present findings to user:
- Code structure summary
- Identified problem areas
- Initial recommendations
- Request approval to proceed
Phase 2: Test Coverage Assessment
Why Tests Matter
"Refactoring without tests is like driving without a seatbelt." — Martin Fowler
What ships with it
5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 6d ago First seen · 435 lines · 64 tokens per session scan A 459b8b4aacdc
refactor is a skill published in the GitHub repository luongnv89/claude-howto (41,371 stars, last pushed 3d ago), licensed MIT. It adds 64 tokens to every session and 2,789 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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