Design Patterns Skill for Claude
A Claude Skill that turns Claude into
a reliable reference for all 23 Gang of Four design patterns. Ask about a
pattern, get help choosing between patterns, or have Claude review and refactor
your code toward the right one — with idiomatic examples in 8 languages, loaded
only when needed instead of dumped into every conversation.
What you get
- All 23 GoF patterns — 5 creational, 7 structural, 11 behavioral — each
with intent, structure, participants, pitfalls, and relations to other patterns.
- Runnable examples in 8 languages: Python, Java, C++, C#, TypeScript, Go,
PHP, Ruby. Claude reads only the language you ask for.
- Code review and refactoring that checks your implementation against the
pattern's roles and known pitfalls — and tells idiomatic variants apart from
real mistakes, so you don't get false alarms.
- Whole-codebase audits: Claude finds candidate pattern implementations,
reports problems in a table, and fixes them only after you approve.
- UML diagrams: generate a pattern's class diagram (or a diagram of the
patterns in your own code) as Mermaid, PlantUML, or an editable draw.io
file.
- Three subagents shipped with the plugin: a mentor (explain / choose /
review / audit), a UML agent (diagrams), and a refactorer that applies a
pattern refactor to your code — plus a
scan_patterns.py codebase scanner.
Install
Claude.ai
- Download the
design-patterns-vX.Y.Z.zip from the
latest release,
or clone this repo and zip the plugins/design-patterns/ folder yourself.
- In Claude.ai: Settings → Capabilities → Skills → Upload skill, select the zip.
- Toggle the skill on.
Claude Code (plugin marketplace — recommended)
This repo doubles as a plugin marketplace,
so you can install it once and get automatic updates instead of copying files by hand.
/plugin marketplace add Mosweed/design-patterns-skill
/plugin install design-patterns@mosweed-plugins
To try it straight from a local clone before it's pushed anywhere:
/plugin marketplace add ./design-patterns-skill
/plugin install design-patterns@mosweed-plugins
Update later with /plugin marketplace update mosweed-plugins, and remove with
/plugin uninstall design-patterns@mosweed-plugins. The same commands work as
claude plugin … from a normal shell.
Claude Code (manual copy)
Prefer not to use a marketplace? Copy the plugins/design-patterns/ folder into a skills directory:
# Personal — available in all your projects
cp -r plugins/design-patterns ~/.claude/skills/
# Or project-scoped — committed with a repo, shared with your team
cp -r plugins/design-patterns .claude/skills/
Restart Claude Code if the skills directory didn't already exist.
GitHub Copilot (custom agent)
This repo also ships a GitHub Copilot custom agent that follows the same
workflow, in agents/design-patterns.agent.md.
To use it in your own workspace, copy it into .github/agents/ so VS Code Copilot
detects it:
mkdir -p .github/agents
cp agents/design-patterns.agent.md .github/agents/
Then select Design Patterns Mentor from the agent dropdown in Copilot Chat.
The agent is self-contained, but if it can see this repo's
plugins/design-patterns/references/, it will use those files as its source of truth.
What it does
The skill picks the right shape for the task automatically:
| You ask | Claude responds with |
|---|
| "Explain the Observer pattern in Go" | Intent, structure, one idiomatic Go example, pitfalls |
| "Strategy or State here?" | A comparison table and a single recommendation |
| "Is this a correct Singleton?" + code | A findings table (correctness / robustness / deviation) |
| "Audit the codebase for pattern mistakes" | A report first; fixes only after you approve |
| "Refactor this if/else toward a pattern" | The target pattern and the smallest safe change |
It will also tell you when no pattern is the better answer, rather than
forcing one.
Repository layout
