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/elct9620/ai-coding-skills/design-patternsnpx skills add elct9620/ai-coding-skills --skill design-patternsgit clone --depth 1 https://github.com/elct9620/ai-coding-skillsWrote 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/elct9620/ai-coding-skills/design-patterns)<a href="https://agentmods.dev/skills/elct9620/ai-coding-skills/design-patterns"><img src="https://agentmods.dev/badge/skills/elct9620/ai-coding-skills/design-patterns.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 | $0.00077 | $0.00793 |
| Opus 5 | $0.00039 | $0.00396 |
| Sonnet 5 | $0.00015 | $0.00159 |
| Haiku 4.5 | $0.00008 | $0.00079 |
Grade A, and why
design-patterns 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.
How it starts
The opening of the file, as written. The whole thing — 101 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Related Skills
- Modeling business concepts (Entity, Value Object)? → Use domain-modeling instead
- Restructuring existing code toward a pattern? → Use refactoring for safe migration steps
- Deciding if a pattern is even needed (YAGNI)? → Use principles to evaluate first
Applicability Rubric
| Condition | Pass | Fail |
|---|---|---|
| Multi-component change | Feature affects multiple components | Single component change |
| Recognizable problem | Matches known design problem | Unique/novel problem |
| Flexibility needed | Requires extensible solution | Fixed requirements |
| Recurring challenge | Solving common design issue | One-off implementation |
Apply when: Any condition passes
Core Principles
Pattern Selection Process
1. Identify the problem
↓
2. Match problem to pattern category
↓
3. Evaluate pattern candidates
↓
4. Consider trade-offs
↓
5. Apply pattern minimally
Pattern Categories
| Category | Purpose | Common Patterns |
|---|---|---|
| Creational | Object creation | Factory, Builder, Singleton |
| Structural | Object composition | Adapter, Decorator, Facade |
| Behavioral | Object interaction | Strategy, Observer, Command |
Pattern Quick Reference
| Category | Pattern | Use When | Example |
|---|---|---|---|
| Creational | Factory Method | Object creation varies by context | createLogger(type) |
| Creational | Builder | Complex object with many optional parts | Fluent configuration |
| Creational | Singleton | Single instance needed globally | Configuration manager |
| Structural | Adapter | Interface incompatibility | Wrap legacy API |
| Structural | Decorator | Add behavior dynamically | Logging wrapper |
| Structural | Facade | Simplify complex subsystem | Unified API client |
| Structural | Composite | Tree structures | UI components |
| Behavioral | Strategy | Algorithm varies at runtime | Payment methods |
| Behavioral | Observer | One-to-many notifications | Event system |
| Behavioral | Command | Encapsulate operations | Undo/redo actions |
| Behavioral | State | Behavior changes with state | Order status |
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 · 101 lines · 0 tokens per session scan A e4c82cf0b133
design-patterns is a skill published in the GitHub repository elct9620/ai-coding-skills (5 stars, last pushed 10d ago), licensed Apache-2.0. It adds 77 tokens to every session and 793 once invoked, about $0.0004 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 2026-08-31.
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