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 302-frameworks-spring-boot-restgit 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/302-frameworks-spring-boot-rest)<a href="https://agentmods.dev/skills/jabrena/plinth/302-frameworks-spring-boot-rest"><img src="https://agentmods.dev/badge/skills/jabrena/plinth/302-frameworks-spring-boot-rest.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00177 | $0.00886 |
| Opus 5 | $0.00088 | $0.00443 |
| Sonnet 5 | $0.00035 | $0.00177 |
| Haiku 4.5 | $0.00018 | $0.00089 |
Grade A, and why
302-frameworks-spring-boot-rest 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 5d 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 — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Java REST API Design Principles
Apply REST API design principles for Spring Boot applications.
What is covered in this Skill?
- HTTP methods (GET, POST, PUT, PATCH, DELETE) — semantic consistency
- Resource URI design
- HTTP status codes
- Request/response DTOs with lean contracts
- API versioning (URI, header, or media type — applied consistently)
- Bean Validation at the boundary (@Valid/@Validated on controller inputs, 400 on failure)
- Pagination, sorting, and filtering (Page/Pageable with caps)
- ISO-8601 instants with offset (OffsetDateTime, Instant) in JSON contracts
- Content negotiation (JSON default; vendor media types when meaningful)
- Idempotency-Key support for POST creates; 409 Conflict for collisions
- ETag concurrency with If-Match/If-None-Match; 412 Precondition Failed / 304 Not Modified
- HTTP caching discipline (Cache-Control, ETag, Last-Modified)
- Deprecation and sunset headers (Deprecation, Sunset, Link rel="successor-version)"
- Error handling
- API security (TLS, authentication, authorization, input validation)
- API contract: OpenAPI file as source of truth for API-first (OpenAPI Generator)
- Controller advice and problem details (RFC 7807)
Scope: Apply recommendations based on the reference rules and good/bad code examples.
Constraints
Before applying any REST API changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification.
- MANDATORY: Run
./mvnw compileormvn compilebefore applying any change - SAFETY: If compilation fails, stop immediately
- VERIFY: Run
./mvnw clean verifyormvn clean verifyafter applying improvements - BEFORE APPLYING: Read the reference for detailed rules and good/bad patterns
- EDGE CASE: If request scope is ambiguous, stop and ask a clarifying question before applying changes
- EDGE CASE: If required inputs, files, or tooling are missing, report what is missing and ask whether to proceed with setup guidance
What ships with it
1 file 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.
- 5d ago First seen · 75 lines · 177 tokens per session scan A 6fce8afc4a44
302-frameworks-spring-boot-rest is a skill published in the GitHub repository jabrena/plinth (436 stars, last pushed 3d ago), licensed Apache-2.0. It adds 177 tokens to every session and 886 once invoked, about $0.0009 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.
Other skills, from other repositories
spring-boot-engineer
Generates Spring Boot 3.x configurations, creates REST controllers, implements Spring Security 6 authentication flows, sets up Spring Data JPA repositories, and configures reactive WebFlux endpoints. Use when building Spring Boot 3.x applications, microservices, or reactive Java applications; invoke for Spring Data…
java-architect
Use when building, configuring, or debugging enterprise Java applications with Spring Boot 3.x, microservices, or reactive programming. Invoke to implement WebFlux endpoints, optimize JPA queries and database performance, configure Spring Security with OAuth2/JWT, or resolve authentication issues and async processing…
spring-boot-patterns
Spring Boot best practices and patterns. Use when creating controllers, services or repositories, or when the user asks about Spring Boot layering, wiring, configuration or exception handling. For JPA and Hibernate behaviour, use jpa-patterns instead.
spring-mvc-to-boot-migrator
Automatically migrate Spring MVC applications to Spring Boot. Use when you need to modernize a Spring MVC project to Spring Boot while preserving functionality. The skill analyzes the codebase, updates build configuration (Maven/Gradle), migrates annotations, converts XML configuration to Java/properties, updates…
craftcms
Craft CMS 5 plugin and module development — extending Craft with PHP. Covers elements, element queries, services, models, records, controllers, migrations, queue jobs, console commands, field types, native fields, events, behaviors, Twig extensions, widgets, filesystems, permissions, project config, GraphQL, testing…
creating-springboot-projects
Use when starting a new Spring Boot 4 project — scaffolding a service, REST API, or modular backend; picking an architecture (layered, package-by-module, modular-monolith, tomato, DDD-hexagonal); selecting Spring Boot 4 features; or applying the bundled templates and references in this skill. Not for migrating…