A refactoring advisor based on Martin Fowler's catalog, a well-known collection of techniques for improving code structure. It identifies code smells, meaning patterns that may make code harder to maintain, and guides changes step by step with tests.

Use it to review code for structural problems, plan and apply refactorings, run tests between changes, and learn refactoring techniques across programming languages.

It helps you improve existing code while checking that each change preserves its behavior, and explains why a particular restructuring may be appropriate.

fowler — Plugin by el-feo

Install

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.

Claude Code

/plugin marketplace add el-feo/ai-context

agentmods

npx agentmods add plugins/el-feo/ai-context/fowler

Clone the repo

git clone --depth 1 https://github.com/el-feo/ai-context

Made for: Claude Code.

Per session not measured What this adds to a session before it is invoked.

When invoked not measured Not applicable: nothing here is loaded into a session.

Security scan A 0 findings. Scan, not verified.

Origin original No closer match found in the catalogue.

Security

Grade A, and why

fowler 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 yesterday.

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.

plugins/fowler/.claude-plugin/plugin.json · 11 lines

What it actually says

{
  "name": "fowler",
  "version": "0.2.1",
  "description": "Refactoring advisor grounded in Martin Fowler's catalog (Refactoring, 2nd ed.). Diagnoses code smells, applies refactorings step-by-step with tests between steps, and teaches when and why to use each technique — language-agnostic",
  "author": {
    "name": "Jeb Coleman"
  },
  "commands": ["./commands/fowler.md", "./commands/install-review.md"],
  "skills": ["./skills/fowler"]
}

Changes

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.

yesterday First seen · 11 lines scan A d41bb2cf518a

Subscribe to this mod's changes

fowler is a plugin published in the GitHub repository el-feo/ai-context (12 stars, last pushed 1mo ago), licensed MIT. Its token cost is not measured: this kind of file is read by the harness, not the model. 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.

Code review Debugging Learning and teaching

fowler

Getting it into your agent

Grade A, and why

Nothing flagged

What it actually says

What this file has done since we first saw it

Other plugins, from other repositories

claude-code-plugin

edulab

Master-skill

ida-plugin-development

cortex

hello-world