agent toolingby skillscatalog
Skill Validator
skillscatalog/skill-validator
Validate Agent Skills against the specification. Checks SKILL.md format, frontmatter fields, naming conventions, and directory structure.
What it changes
Passed 19 of 21 test cases with the skill, and 10 of 21 without it.
Without skill45%
With skill91%
Checks it passed that the model alone missed
- Specify Python 3.9 minimum requirement.
- Specify that skill names must use hyphens.
- State that PyYAML is optional, falling back to basic parsing.
and 9 more in the full report
10 fixed10 passed either way2 still failing0 broke
- Pass-rate lift
- +45 pp
- Tokens
- -16%
- Agent turns
- 0%
- Response time
- -56%
Model gemini-3.6-flashMeasured 8/6/2026v120 of 22 cases passed with skill · 21 comparable
See it in action
One of 10 test cases the skill fixed. Same model, same prompt, with and without the skill.
PromptWhat Python runtime version is required to run the local validation script for agent skills?
What was checked, without and with the skill| Checked | Without skill | With skill |
|---|
| Specify Python 3.9 minimum requirement. | Missed | Passed |
|---|
What's inside
The instructions your model reads when the skill loads.
SKILL.md96 lines2 filesincludes scripts
Instructions
Use this skill to validate any Agent Skill directory against the specification before publishing. The validator checks:
- SKILL.md presence - Required manifest file exists
- Frontmatter format - Valid YAML frontmatter with required fields
- Name validation - 1-64 chars, lowercase, hyphens only, starts with letter
- Name-directory match - Name field matches the directory name
- Description validation - 1-1024 characters, non-empty
- Structure validation - Valid folder organization
When to Use
- Before submitting a skill for publication
- After making changes to SKILL.md
- To diagnose why a skill was rejected
- As part of CI/CD pipelines
How to Use
Validate a skill directory:
Validate the skill at /path/to/my-skill
Get JSON output for CI integration:
python3 validate_skill.py /path/to/my-skill --json
Output
✓ Skill Validation Report
Skill: pdf-tools
Status: COMPLIANT (100/100)
Checks:
Track record
Benchmark
19 / 21
test cases passed, vs 10 / 21 without
Adoption
- Users
- 0
- Times used
- 0
Safety and source details
SkillSafety
✓ 3 of 3 passed✓Code scan15 of 15 checks clean
0 critical · 0 warning · 0 info — scanner v4 — 8/2/2026
View 15 scanner checks
live_secretremote_code_executionreverse_shelldata_exfiltrationssrf_metadataagent_snoopinganti_refusaldestructive_commandsobfuscated_unicodeunicode_homoglyphopaque_blobsuspicious_urltool_overreachtrigger_abuseprompt_injection_phrasing
✓IntentSafe
LLM judge · does the skill do what it claims
✓ContentClean
LLM judge · policy & harmful-content review
Source
ImportedLicense MITImported 8/2/2026Version v1Bundled 1 file · scripts