> ## Documentation Index
> Fetch the complete documentation index at: https://lab.pollack.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Agent Skills

> Curated domain knowledge modules — SkillsJars that make agents smarter without prompt engineering

<Info>
  This is a Spring AI Community project (`spring-ai-community/spring-testing-skills`) and is not part of the AgentWorks platform. It uses its own repository and Maven coordinates (`org.springaicommunity`).
</Info>

Skills are curated knowledge packages that teach agents how to do specific things well. Each skill is a structured Markdown file with routing rules and reference patterns. Agents discover skills at startup and load full content only when relevant — no tokens wasted on unused knowledge.

Skills follow the [SkillsJars](https://skillsjars.io) specification and work in any agentic CLI — Loopy, Claude Code, and 40+ others.

## Spring Testing Skills

The first production-ready SkillsJars collection — 7 skills that teach agents how to test Spring applications.

| Skill                           | Domain                                                                            |
| ------------------------------- | --------------------------------------------------------------------------------- |
| **spring-testing-router**       | Meta-skill — routes to the right domain skill based on the task                   |
| **spring-jpa-testing**          | `@DataJpaTest`, Testcontainers, `@ServiceConnection`, Hibernate 6/7, lazy loading |
| **spring-mvc-testing**          | `@WebMvcTest`, `MockMvc`, `jsonPath`, request validation, `@RestControllerAdvice` |
| **spring-security-testing**     | `@WithMockUser`, CSRF, JWT, OAuth2, `@PreAuthorize` method security               |
| **spring-webflux-testing**      | `@WebFluxTest`, `WebTestClient`, `StepVerifier`, virtual time, SSE                |
| **spring-websocket-testing**    | STOMP/WebSocket, `WebSocketStompClient`, `BlockingQueue` pattern                  |
| **spring-testing-fundamentals** | AssertJ, BDDMockito, `ArgumentCaptor`, context caching, anti-patterns             |

### Skill Structure

Each skill has a `SKILL.md` with metadata and routing rules, plus a `references/` directory with detailed patterns:

```
skills/spring-jpa-testing/
├── SKILL.md                       # Metadata + routing rules
└── references/
    ├── testcontainers.md          # Detailed patterns
    ├── transactional-tests.md
    ├── lazy-loading-tests.md
    └── hibernate-6-migration.md
```

### Install

```bash theme={null}
git clone https://github.com/spring-ai-community/spring-testing-skills.git
cd spring-testing-skills
./mvnw package
mvn skillsjars:extract -Ddir=~/.claude/skills
```

Skills are extracted to `~/.claude/skills/` where any agentic CLI discovers them automatically.

## Evidence

In the [Code Coverage v2](/experiments/code-coverage-v2) experiment, adding testing skills:

* Reduced JAR\_INSPECT tool calls from **11.0% → 1.0%** — the agent stopped inspecting dependencies because the skills already provided the knowledge
* Reduced expected steps by **\~25%** compared to baseline

<Warning>
  **Updated 2026-08-27 — the absolute figures are withdrawn.** This read *"25% (224 vs 301)."* The
  `224` reproduces exactly from a chain that grouped by item rather than by run: v2 ran 2–3 runs
  against a single item, so every run of a variant was concatenated into one sequence, losing all but
  one absorption event and inflating expected steps about threefold (defect **CT6**). Recomputed with
  trajectories separated: **74.7 vs \~101–109**, depending on which baseline arm is meant — the page
  does not say, which is its own defect.

  **The \~25% survives** because both arms were inflated by the same factor. The absolute numbers do
  not. See the [v2 experiment page](/experiments/code-coverage-v2) and
  `agent-control-theory` `d18fc50`.
</Warning>

This validates the thesis: curated knowledge improves agent quality more than model upgrades.

## Creating Custom Skills

Any Markdown file with YAML frontmatter can be a skill:

```markdown theme={null}
---
name: my-team-conventions
description: Coding conventions for our Spring Boot services
---

# Instructions

When working on this codebase:
- Use constructor injection, never field injection
- All REST endpoints return ProblemDetail for errors (RFC 9457)
- Tests use @WebMvcTest with MockMvc, not @SpringBootTest
```

Place in `.claude/skills/my-conventions/SKILL.md` (project) or `~/.claude/skills/my-conventions/SKILL.md` (global).

## Documentation

<CardGroup cols={2}>
  <Card title="Spring Testing Skills" icon="github" href="https://github.com/spring-ai-community/spring-testing-skills">
    7 skills with routing table and reference patterns
  </Card>

  <Card title="SkillsJars Spec" icon="book" href="https://skillsjars.io">
    The SkillsJars format — portable domain knowledge for any agentic CLI
  </Card>
</CardGroup>