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/cookiemonsterdev/agents-skills/design-patternsnpx skills add cookieMonsterDev/agents-skills --skill design-patternsgit clone --depth 1 https://github.com/cookieMonsterDev/agents-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/cookiemonsterdev/agents-skills/design-patterns)<a href="https://agentmods.dev/skills/cookiemonsterdev/agents-skills/design-patterns"><img src="https://agentmods.dev/badge/skills/cookiemonsterdev/agents-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 | $0.00104 | $0.01597 |
| Opus 5 | $0.00052 | $0.00798 |
| Sonnet 5 | $0.00021 | $0.00319 |
| Haiku 4.5 | $0.00010 | $0.00160 |
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 4d 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 — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Design Patterns
Ground design-pattern answers in the reference files bundled with this skill instead of improvising definitions. Each pattern has a reference file explaining it and a folder of runnable examples in popular languages.
When to Use
- The user names a pattern directly ("show me the builder pattern in Rust")
- The user describes a design problem that maps to a pattern ("I need to create objects without specifying their concrete class")
- The user asks to compare patterns ("strategy vs state?")
- The user wants existing code refactored toward a pattern
Workflow
- Identify the pattern(s) from the user's question using the catalog below.
- Read the reference file at
references/<pattern>.mdfor the explanation, applicability, trade-offs, and related patterns. - Read the language example at
examples/<pattern>/<pattern>.<ext>when the user works in (or asks for) a specific language. Adapt it to their domain rather than pasting the generic example verbatim. - Answer with: what the pattern does, when to use it (and when not to), and code adapted to the user's context.
If the user's problem does not match any pattern cleanly, say so — do not force a pattern where a plain function or data structure is simpler.
Pattern Catalog
Creational
Patterns that abstract the instantiation process.
| Pattern | Intent | Reference |
|---|---|---|
| Abstract Factory | Create families of related objects without specifying concrete classes | references/abstract-factory.md |
| Builder | Construct complex objects step by step, separating construction from representation | references/builder.md |
| Factory Method | Let subclasses decide which class to instantiate | references/factory-method.md |
| Prototype | Create objects by cloning an existing instance | references/prototype.md |
| Singleton | Ensure a class has one instance with a global access point | references/singleton.md |
What ships with it
60 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.
- examples/abstract-factory/abstract-factory.c 2.0 KB
- examples/abstract-factory/abstract-factory.cpp 2.2 KB
- examples/abstract-factory/abstract-factory.cs 1.8 KB
- examples/abstract-factory/abstract-factory.go 1.8 KB
- examples/abstract-factory/abstract-factory.java 2.0 KB
- examples/abstract-factory/abstract-factory.js 1.3 KB runs code
- examples/abstract-factory/abstract-factory.php 2.0 KB
- examples/abstract-factory/abstract-factory.py 1.9 KB runs code
- examples/abstract-factory/abstract-factory.rs 2.1 KB
- examples/abstract-factory/abstract-factory.swift 1.6 KB
- examples/adapter/adapter.c 2.5 KB
- examples/adapter/adapter.cpp 2.0 KB
- examples/adapter/adapter.cs 1.6 KB
- examples/adapter/adapter.go 1.4 KB
- examples/adapter/adapter.java 2.0 KB
- examples/adapter/adapter.js 1.2 KB runs code
- examples/adapter/adapter.php 1.5 KB
- examples/adapter/adapter.py 1.8 KB runs code
- examples/adapter/adapter.rs 1.5 KB
- examples/adapter/adapter.swift 1.3 KB
- examples/bridge/bridge.c 2.0 KB
- examples/bridge/bridge.cpp 2.3 KB
- examples/bridge/bridge.cs 1.9 KB
- examples/bridge/bridge.go 1.5 KB
- examples/bridge/bridge.java 2.3 KB
- examples/bridge/bridge.js 1.3 KB runs code
- examples/bridge/bridge.php 1.8 KB
- examples/bridge/bridge.py 2.0 KB runs code
- examples/bridge/bridge.rs 1.8 KB
- examples/bridge/bridge.swift 1.6 KB
- examples/builder/builder.c 2.3 KB
- examples/builder/builder.cpp 2.8 KB
- examples/builder/builder.cs 2.1 KB
- examples/builder/builder.go 2.4 KB
- examples/builder/builder.java 2.6 KB
- examples/builder/builder.js 1.5 KB runs code
- examples/builder/builder.php 1.8 KB
- examples/builder/builder.py 1.7 KB runs code
- examples/builder/builder.rs 2.0 KB
- examples/builder/builder.swift 1.9 KB
- examples/chain-of-responsibility/chain-of-responsibility.c 1.8 KB
- examples/chain-of-responsibility/chain-of-responsibility.cpp 1.9 KB
- examples/chain-of-responsibility/chain-of-responsibility.cs 2.0 KB
- examples/chain-of-responsibility/chain-of-responsibility.go 1.3 KB
- examples/chain-of-responsibility/chain-of-responsibility.java 2.2 KB
- examples/chain-of-responsibility/chain-of-responsibility.js 1.4 KB runs code
- examples/chain-of-responsibility/chain-of-responsibility.php 2.0 KB
- examples/chain-of-responsibility/chain-of-responsibility.py 1.9 KB runs code
- examples/chain-of-responsibility/chain-of-responsibility.rs 1.9 KB
- examples/chain-of-responsibility/chain-of-responsibility.swift 1.8 KB
- examples/command/command.c 2.3 KB
- examples/command/command.cpp 2.1 KB
- examples/command/command.cs 2.2 KB
- examples/command/command.go 1.6 KB
- examples/command/command.java 2.5 KB
- examples/command/command.js 1.3 KB runs code
- examples/command/command.php 2.1 KB
- examples/command/command.py 2.1 KB runs code
- examples/command/command.rs 2.1 KB
- examples/command/command.swift 1.7 KB
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.
- 4d ago First seen · 99 lines · 104 tokens per session scan A 02f274d52427
design-patterns is a skill published in the GitHub repository cookieMonsterDev/agents-skills (4 stars, last pushed 15d ago), licensed MIT. It adds 104 tokens to every session and 1,597 once invoked, about $0.0005 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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