Spring Boot Engineer

What it does

When your agent uses it

• Building a REST API with Spring Boot 3 controllers and validation
• Setting up Spring Data JPA repositories and transactions
• Adding Spring Security 6 with OAuth2 or JWT
• Writing reactive endpoints with WebFlux
• Testing with MockMvc and Testcontainers and checking Actuator health

Example prompts

• “Create a products feature with an entity, repository, service, controller and a record DTO.”
• “Secure the admin endpoints with Spring Security 6 and method-level checks.”
• “Write MockMvc tests for the orders controller and a Testcontainers test for its repository.”
• “The actuator health endpoint reports DOWN, so find which component fails and fix it.”

Requirements

• Java with Maven or Gradle

Workflow steps

6 steps, taken from the first numbered list in SKILL.md.

1. 1Analyze requirements — Identify service boundaries, APIs, data models, security needs
2. 2Design architecture — Plan microservices, data access, cloud integration, security; confirm design before coding
3. 3Implement — Create services with constructor injection and layered architecture (see Quick Start below)
4. 4Secure — Add Spring Security, OAuth2, method security, CORS configuration; verify security rules compile and pass tests. If compilation or…
5. 5Test — Write unit, integration, and slice tests; run ./mvnw test (or ./gradlew test) and confirm all pass before proceeding. If tests…
6. 6Deploy — Configure health checks and observability via Actuator; validate /actuator/health returns UP. If health is DOWN: check the…

What it can do on your machine

Read from SKILL.md and the folder at commit 1be15d8. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are java).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • github.com
  • synergetic.solutions
  • jeffallan.github.io

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Spring Boot Engineer loads about 1.9k tokens when it runs, and up to ~18k if it reads all its reference files. Until then it costs about 114 tokens; SKILL.md has 381 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~114

When it runs · the whole SKILL.md, loaded when a task matches

~1.9k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~18k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from Jeffallan/claude-skills at commit 1be15d8, republished under its MIT licence (© Jeffallan). 381 words, ~1,877 tokens.

name

spring-boot-engineer

description

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 JPA, Spring Security 6, WebFlux, Spring Cloud integration, Java REST API design, or Microservices Java architecture.

license

MIT

metadata.author

https://github.com/Jeffallan

metadata.company

https://synergetic.solutions

metadata.version

1.1.0

metadata.domain

backend

metadata.triggers

Spring Boot, Spring Framework, Spring Cloud, Spring Security, Spring Data JPA, Spring WebFlux, Microservices Java, Java REST API, Reactive Java

metadata.role

specialist

metadata.scope

implementation

metadata.output-format

code

metadata.related-skills

java-architect, database-optimizer, microservices-architect, devops-engineer

@Entity
@Table(name = "products")
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotBlank
    private String name;

    @DecimalMin("0.0")
    private BigDecimal price;

    // getters / setters or use @Data (Lombok)
}

public interface ProductRepository extends JpaRepository<Product, Long> {
    List<Product> findByNameContainingIgnoreCase(String name);
}

@Service
public class ProductService {
    private final ProductRepository repo;

    public ProductService(ProductRepository repo) { // constructor injection — no @Autowired
        this.repo = repo;
    }

    @Transactional(readOnly = true)
    public List<Product> search(String name) {
        return repo.findByNameContainingIgnoreCase(name);
    }

    @Transactional
    public Product create(ProductRequest request) {
        var product = new Product();
        product.setName(request.name());
        product.setPrice(request.price());
        return repo.save(product);
    }
}

@RestController
@RequestMapping("/api/v1/products")
@Validated
public class ProductController {
    private final ProductService service;

    public ProductController(ProductService service) {
        this.service = service;
    }

    @GetMapping
    public List<Product> search(@RequestParam(defaultValue = "") String name) {
        return service.search(name);
    }

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public Product create(@Valid @RequestBody ProductRequest request) {
        return service.create(request);
    }
}

public record ProductRequest(
    @NotBlank String name,
    @DecimalMin("0.0") BigDecimal price
) {}

@RestControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public Map<String, String> handleValidation(MethodArgumentNotValidException ex) {
        return ex.getBindingResult().getFieldErrors().stream()
            .collect(Collectors.toMap(FieldError::getField, FieldError::getDefaultMessage));
    }

    @ExceptionHandler(EntityNotFoundException.class)
    @ResponseStatus(HttpStatus.NOT_FOUND)
    public Map<String, String> handleNotFound(EntityNotFoundException ex) {
        return Map.of("error", ex.getMessage());
    }
}

@WebMvcTest(ProductController.class)
class ProductControllerTest {
    @Autowired MockMvc mockMvc;
    @MockBean ProductService service;

    @Test
    void createProduct_validRequest_returns201() throws Exception {
        var product = new Product(); product.setName("Widget"); product.setPrice(BigDecimal.TEN);
        when(service.create(any())).thenReturn(product);

        mockMvc.perform(post("/api/v1/products")
                .contentType(MediaType.APPLICATION_JSON)
                .content("""{"name":"Widget","price":10.0}"""))
            .andExpect(status().isCreated())
            .andExpect(jsonPath("$.name").value("Widget"));
    }
}

© Jeffallan, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 5 other files (references) in skills/spring-boot-engineer of Jeffallan/claude-skills.

• SKILL.md
• references/cloud.md
• references/data.md
• references/security.md
• references/testing.md
• references/web.md

Open the folder on GitHubat commit 1be15d8