# Lint

> Fix code style issues and ensure linting CI gates pass in S3Mock. Use when ktlint or Checkstyle violations are reported, when asked to fix formatting, or as a required final step after any code change. Runs ktlint for Kotlin source files and Checkstyle for Java and XML files. Use when this capability is needed.

- Skill: `tomevault-io/lint-2` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add tomevault-io/lint-2`
- Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/lint-2/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: tomevault-io (https://skillmd.com/u/tomevault-io)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/tomevault-io/lint-2

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# Lint Skill

## Entry Criteria

Use this skill when:
- ktlint or Checkstyle violations are reported
- Asked to fix formatting issues
- Invoked as a final step by the `implement`, `test`, or `refactor` skill

## Tools

| Tool | Target | Config | Auto-fix? |
|---|---|---|---|
| **ktlint** | Kotlin source files | `.editorconfig` | Yes — `make format` |
| **Checkstyle** | Java source + XML files | `etc/checkstyle.xml` | No — fix manually |

## Execution Steps

1. **`make format`** — auto-formats all Kotlin files with ktlint. Fixes the vast majority of Kotlin style issues.
2. **`make lint`** — reports ktlint and Checkstyle violations. Fix Checkstyle (Java/XML) violations manually.
3. **`make sort`** — run this if any `pom.xml` was added or modified during this task.
4. Fix any remaining violations manually (see resources below for style guides).
5. **`make install`** — confirm all linting CI gates pass before finishing.

## Common Violations

### ktlint (Kotlin)

`make format` auto-fixes most of these:
- Wrong indentation (2 spaces)
- Unused or wildcard imports
- Missing trailing newline
- Line too long (max 120 characters)

To check without modifying files: `make lint`

### Checkstyle (Java / XML)

Fix these manually:
- Wrong indentation (2 spaces, per `.editorconfig`)
- Line too long (max 120 characters)
- Import ordering
- Missing or malformed Javadoc

## Completion Criteria

- [ ] `make format` run (Kotlin auto-fixed)
- [ ] `make lint` passes with no violations
- [ ] `make sort` run if any `pom.xml` was modified
- [ ] `make install` passes all CI gates

## Resources

- [`AGENTS.md`](../../../AGENTS.md) — build command reference
- [`docs/KOTLIN.md`](../../../docs/KOTLIN.md) — Kotlin style conventions
- [`docs/JAVA.md`](../../../docs/JAVA.md) — Java style conventions
- [`etc/checkstyle.xml`](../../../etc/checkstyle.xml) — Checkstyle configuration
- [`.editorconfig`](../../../.editorconfig) — indentation and line-length settings

---
> Source: [adobe/S3Mock](https://github.com/adobe/S3Mock) — distributed by [TomeVault](https://tomevault.io).
<!-- tomevault:4.0:skill_md:2026-06-19 -->