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 skills add jabrena/plinth --skill 123-java-design-patternsgit clone --depth 1 https://github.com/jabrena/plinthWrote 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/jabrena/plinth/123-java-design-patterns)<a href="https://agentmods.dev/skills/jabrena/plinth/123-java-design-patterns"><img src="https://agentmods.dev/badge/skills/jabrena/plinth/123-java-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 | $0.00089 | $0.00911 |
| Opus 5 | $0.00044 | $0.00456 |
| Sonnet 5 | $0.00018 | $0.00182 |
| Haiku 4.5 | $0.00009 | $0.00091 |
Grade A, and why
123-java-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 — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Java Design and Integration Patterns
Guide Java developers in selecting patterns by problem signal, implementation context, and trade-off rather than by pattern name alone.
What is covered in this Skill?
- Classic Java design patterns for application code: creational, structural, and behavioral patterns
- REST API patterns for resource design, contracts, idempotency, versioning, and error handling
- Kafka and event-driven patterns for event schemas, partitioning, idempotency, retries, outbox, and sagas
- Database and persistence patterns for repositories, transactions, aggregates, locking, migrations, and read models
- Cross-cutting integration patterns for anti-corruption layers, resilience, observability, and reliable message boundaries
Scope: Use this skill to explain, review, and implement practical patterns in Java systems. Prefer simple code first; introduce a pattern only when it reduces real complexity, protects a boundary, improves testability, or makes change safer.
Constraints
Pattern guidance must be problem-led, concrete, and safe to apply in Java projects.
- PROBLEM FIRST: Identify the design pressure before naming or applying a pattern
- NO PATTERN SHOPPING: Do not add abstractions only because a pattern exists; prefer simple code when variation is not present
- BUILD SAFETY: For code changes, run
./mvnw compileormvn compilebefore refactoring and./mvnw clean verifyormvn clean verifyafter changes - REFERENCE SELECTION: Read the relevant reference before acting: Java code patterns, REST API patterns, Kafka/event-driven patterns, database/persistence patterns, or cross-cutting integration patterns
- TRADE-OFFS REQUIRED: Explain the benefit, cost, and when-not-to-use guidance for any recommended pattern
When to use this skill
- Apply Java design patterns
- Review Java code for design patterns
- Choose REST API patterns
- Design Kafka event-driven patterns
- Improve database persistence patterns
- Add resilient integration patterns
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.
- 4d ago First seen · 73 lines · 89 tokens per session scan A 6f7a11ff6c34
123-java-design-patterns is a skill published in the GitHub repository jabrena/plinth (436 stars, last pushed 2d ago), licensed Apache-2.0. It adds 89 tokens to every session and 911 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 2026-09-03.
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