skillcheck
Validates skill quality โ preprocessing safety, frontmatter, line counts, references. Use when checking skills, validating SKILL.md, or when skillcheck, lint skill, or validate skill are mentioned.
Source facts
- Repository
- outfitter-dev/outfitter
- Last source activity
- February 25, 2026 at 16:13
- Detected SKILL.md language
- English
- Stars
- 6
- Forks
- 1
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SKILL.md
Source instructions ยท Read-only preview- name
- skillcheck
- description
- Validates skill quality โ preprocessing safety, frontmatter, line counts, references. Use when checking skills, validating SKILL.md, or when skillcheck, lint skill, or validate skill are mentioned.
- context
- fork
- metadata
- {"version":"1.0.1","author":"outfitter","preprocess":true,"related-skills":["skillcraft","claude-craft"]}
- allowed-tools
- Read, Glob, Grep, Bash, Task
- argument-hint
- [path]
# Skills Check
Validate skill quality across one or more skill directories.
## Preprocessing Lint
Scan SKILL.md files for `` <bang>`command` `` patterns that trigger Claude Code's preprocessor unintentionally:
!`bun ${CLAUDE_PLUGIN_ROOT}/skills/skillcheck/scripts/lint-preprocessing.ts ${ARGUMENTS:-${CLAUDE_PLUGIN_ROOT}}`
## Interpreting Results
The linter reports:
- File path and line number of each finding
- The matched pattern and surrounding context
- Summary counts (clean, skipped, issues)
### Fixing Issues
| Finding | Fix |
| ----------------------------------------------- | ---------------------------------------------- |
| Unintentional `` <bang>`command` `` in SKILL.md | Replace `!` with `<bang>` |
| Intentional preprocessing | Add `metadata.preprocess: true` to frontmatter |
### The `<bang>` Convention
SKILL.md files are preprocessed by Claude Code โ any `` <bang>`command` `` syntax executes when the skill loads. To safely document or reference the syntax:
- In SKILL.md: use `<bang>` as a stand-in for `!`
- In reference files (references/, EXAMPLES.md): literal `!` is fine and encouraged
- In command files (commands/\*.md): literal `!` is required (that's the feature)
Skills that intentionally preprocess (running scripts at load time) should declare it:
```yaml
metadata:
preprocess: true
```
## Additional Checks
Beyond preprocessing, verify skill quality with existing tools:
```bash
# Frontmatter validation
bun ${CLAUDE_PLUGIN_ROOT}/scripts/validate-skill-frontmatter.ts <path-to-SKILL.md>
# Full plugin validation
bun ${CLAUDE_PLUGIN_ROOT}/scripts/validate-plugin.ts <plugin-directory>
```
## Deep Validation
After reviewing linter results, spawn the `quartermaster` agent to run deeper validation โ frontmatter schema, naming conventions, description quality, line counts, and reference integrity. Pass it the same path argument.
## Quality Checklist
- [ ] No unintentional `` <bang>`command` `` in SKILL.md (this linter)
- [ ] Valid frontmatter (name, description, required fields)
- [ ] SKILL.md under 500 lines
- [ ] All referenced files exist
- [ ] Description has WHAT + WHEN + trigger keywords
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