skill-tester – Coding skill for AI agents

Skill Tester

Tier: POWERFUL · Category: Engineering Quality Assurance · Dependencies: None (Python stdlib only)

Meta-skill that validates, tests, and scores skills in this repository. Four tools, run from the repo root with full paths:

1. scripts/skill_validator.py — structure + documentation compliance

2. scripts/script_tester.py — Python script syntax/imports/runtime/output testing

3. scripts/quality_scorer.py — multi-dimensional scoring with letter grade

4. scripts/security_scorer.py — security posture scoring (also available via quality_scorer.py --include-security)

> Scope note: this skill's tier line-count minimums measure *legacy* skills. For authoring *new* skills, engineering/write-a-skill (SKILL.md under ~100 lines, Matt Pocock doctrine) is the binding standard — do not pad a new skill to satisfy a tier minimum here.

Quick Start (exact, runnable from repo root)

# 1. Validate structure (exit non-zero on failure — usable as a gate)
python3 engineering/skills/skill-tester/scripts/skill_validator.py engineering/skills/self-eval --json

# 2. Test the skill's Python scripts (30s default timeout per script)
python3 engineering/skills/skill-tester/scripts/script_tester.py engineering/skills/self-eval --json

# 3. Score quality (fail CI below threshold with --minimum-score)
python3 engineering/skills/skill-tester/scripts/quality_scorer.py engineering/skills/self-eval --json --detailed --minimum-score 75

Consume the JSON: validator emits overall_score, compliance_level, per-check checks{}; scorer emits overall_score, letter_grade, tier_recommendation, dimensions, and an improvement_roadmap — work the roadmap top-down, then re-run until the target score is met.

For repo-wide auditing prefer scripts/audit_skills.py at the repo root (wraps the write-a-skill checklist runner across all skills).

What Each Tool Checks

skill_validator.py

• SKILL.md frontmatter parsing, required sections, minimum line counts per tier (--tier BASIC|STANDARD|POWERFUL)
• Required structure: SKILL.md, README.md, scripts/, references/, assets/, expected_outputs/
• Python scripts: argparse present, stdlib-only imports

script_tester.py

• AST-based syntax validation; import analysis (flags external dependencies)
• Controlled execution with timeout protection (--timeout, default 30s)
• --help functionality verification; sample-data runs compared against expected_outputs/

quality_scorer.py

Four dimensions, 25% each: Documentation (depth, examples, references), Code Quality (complexity, error handling, output consistency), Completeness (required dirs, sample data, expected outputs), Usability (help text, example clarity). Outputs 0-100 + A-F grade + tier recommendation.

Tier Classification

| Tier | SKILL.md | Scripts | CLI surface |

|---|---|---|---|

| BASIC | ≥ 100 lines | 1 (100-300 LOC) | basic argparse |

| STANDARD | ≥ 200 lines | 1-2 (300-500 LOC) | subcommands, JSON + text output |

| POWERFUL | ≥ 300 lines | 2-3 (500-800 LOC) | multiple modes, CI integration |

(Advisory for legacy skills; new skills follow write-a-skill — see scope note above.)

CI Integration

# GitHub Actions: gate changed skills
- name: "validate-changed-skills"
  run: |
    for skill in $changed_skills; do
      python3 engineering/skills/skill-tester/scripts/skill_validator.py "$skill" --json
      python3 engineering/skills/skill-tester/scripts/script_tester.py "$skill"
      python3 engineering/skills/skill-tester/scripts/quality_scorer.py "$skill" --minimum-score 75
    done

Pre-commit hook: run the validator on the staged skill directory and block the commit on non-zero exit.

Verification Loop

A skill "passes" when, in one run from repo root:

1. skill_validator.py <skill> --json exits 0,

2. script_tester.py <skill> reports all scripts passing, and

3. quality_scorer.py <skill> --minimum-score <target> exits 0.

If any step fails, apply the top improvement_roadmap item and re-run all three — never report a partial pass.

Troubleshooting

• Timeout errors → raise --timeout or optimize the script under test
• Import failures → external deps detected; stdlib-only is the repo policy
• Tier misclassification → check line counts/LOC against the tier table; remember the write-a-skill exception for new skills

References: references/ holds the structure specification, tier requirements matrix, and scoring rubric the tools implement.