Code Quality Scan Skill

Domain knowledge for code quality scanning across multiple languages. Agents load this skill to understand the scanner architecture, tool stack, output format, severity classification, and compliance thresholds.

Scanner Architecture

The code quality scanner uses a 4-tool architecture with a MegaLinter orchestrator for maximum language coverage:

Tool	Role	Technology
Per-language linters	Static analysis for style, correctness, and best practices	ESLint, Ruff, golangci-lint, .NET Analyzers, Checkstyle/PMD
jscpd	Code duplication detection across files and languages	jscpd (native SARIF output)
Lizard	Cyclomatic complexity and function length analysis	Lizard CLI (converter: lizard-to-sarif.py)
Per-language coverage	Test coverage measurement and gap identification	jest, pytest-cov, Coverlet, JaCoCo, go test -cover (converter: coverage-to-sarif.py)
MegaLinter (orchestrator)	Multi-language aggregation and native SARIF output	MegaLinter v8+

Scan Flow

1. Run MegaLinter with per-language linter configuration (.mega-linter.yml).
2. Run jscpd with .jscpd.json config for duplication detection.
3. Run Lizard for complexity analysis and pipe output through lizard-to-sarif.py.
4. Run per-language coverage tools and pipe output through coverage-to-sarif.py.
5. Aggregate all SARIF outputs into a unified result set.
6. Upload to GitHub Security tab (codeql-action/upload-sarif@v4) or ADO Advanced Security (AdvancedSecurity-Publish@1).

SARIF Output Format

The scanner produces SARIF v2.1.0 compliant output.

Required SARIF Fields

Field	Value
$schema	https://raw.githubusercontent.com/oasis-tcs/sarif-spec/main/sarif-2.1/schema/sarif-schema-2.1.0.json
version	2.1.0
tool.driver.name	code-quality-scanner
automationDetails.id	code-quality/coverage/<project>
partialFingerprints	Hash of ruleId:file:function for deduplication
results[].ruleId	Unique rule ID per finding type (e.g., coverage-below-threshold, ccn-exceeded)
results[].level	Mapped from severity (see severity mapping)
help.markdown	Rule description, threshold reference, remediation guidance
properties.tags	Includes code-quality plus category tags (coverage, complexity, duplication, lint)

SARIF Enrichment

• help.markdown — Embeds rule description, threshold reference, and remediation guidance (GitHub does not render helpUri; URLs must be embedded in markdown).
• properties.precision — very-high for direct measurements (coverage, CCN), high for lint findings.
• properties.tags — Includes code-quality tag plus category tags for GitHub filtering.
• partialFingerprints — Hash of ruleId:file:function for deduplication across runs.
• automationDetails.id — Category prefix code-quality/coverage/ for multi-tool scenarios.

Severity Mapping

Condition	SARIF Level	Description
Coverage < 50%, CCN > 20, critical lint errors	error	Immediate action required — block merge
Coverage 50–79%, CCN 11–20, moderate lint warnings	warning	Should be addressed in current sprint
Coverage 80–89%, CCN 6–10, minor style issues	note	Track for future improvement
Coverage ≥ 90%, CCN ≤ 5	Pass	No finding generated

CWE Mapping

Finding Type	CWE ID	Description
High cyclomatic complexity	CWE-1121	Excessive McCabe Cyclomatic Complexity
Code duplication	CWE-1041	Use of Redundant Code
Missing error handling	CWE-754	Improper Check for Unusual Conditions

Thresholds

All projects must maintain the following minimum quality levels, as defined in instructions/code-quality.instructions.md:

Metric	Threshold	Enforcement
Line coverage	≥ 80%	CI gate — block merge if below
Branch coverage	≥ 80%	CI gate — block merge if below
Function coverage	≥ 80%	CI gate — block merge if below
New code coverage	≥ 90%	PR check — warn if below
Cyclomatic complexity	≤ 10 per function	CI gate — block merge if exceeded
Nesting depth	≤ 4 levels	CI gate — block merge if exceeded
Function length	≤ 50 lines	Review — warn if exceeded
Duplication	< 10 similar consecutive lines	Review — flag for extraction

SARIF Converter Patterns

Two converters transform tool-native output into SARIF v2.1.0:

coverage-to-sarif.py

Usage: coverage-to-sarif.py --input <coverage-file> --format <format> --output <sarif-file> [--threshold 80]

Supported formats: cobertura, json-summary, lcov, jacoco, gocover

• Accepts Cobertura XML (pytest-cov, Coverlet), JSON summary (jest), lcov, JaCoCo XML, and Go cover profiles.
• Emits one SARIF result per file below the coverage threshold.
• Sets automationDetails.id to code-quality/coverage/.

lizard-to-sarif.py

Usage: lizard-to-sarif.py --input <lizard-csv> --output <sarif-file> [--ccn-threshold 10] [--length-threshold 50]

• Accepts Lizard CSV output (lizard --csv).
• Maps each function exceeding the CCN or length threshold to a SARIF result.
• Sets automationDetails.id to code-quality/complexity/.

CI/CD Integration

GitHub Actions

- name: Run MegaLinter
  uses: oxsecurity/megalinter@v8
  env:
    VALIDATE_ALL_CODEBASE: true
    SARIF_REPORTER: true

- name: Run complexity analysis
  run: |
    lizard --csv src/ > lizard-output.csv
    python scripts/lizard-to-sarif.py --input lizard-output.csv --output complexity.sarif

- name: Run coverage
  run: |
    npm test -- --coverage --coverageReporters=json-summary
    python scripts/coverage-to-sarif.py --input coverage/coverage-summary.json --format json-summary --output coverage.sarif

- name: Upload SARIF
  uses: github/codeql-action/upload-sarif@v4
  with:
    sarif_file: ./results
    category: code-quality/coverage

Azure DevOps

- script: |
    npx mega-linter-runner --flavor dotnetweb
  displayName: 'Run MegaLinter'

- script: |
    lizard --csv src/ > lizard-output.csv
    python scripts/lizard-to-sarif.py --input lizard-output.csv --output $(Build.ArtifactStagingDirectory)/complexity.sarif
  displayName: 'Complexity Analysis'

- task: AdvancedSecurity-Publish@1
  inputs:
    SarifFileDirectory: '$(Build.ArtifactStagingDirectory)'

Per-Language Tool Reference

Language	Linter	Coverage	Config
TypeScript/JavaScript	ESLint	jest / vitest	eslint.config.mjs, jest.config.ts
Python	Ruff	pytest-cov	pyproject.toml
C#	.NET Analyzers	Coverlet	*.csproj, .editorconfig
Java	Checkstyle / PMD	JaCoCo	pom.xml, checkstyle.xml
Go	golangci-lint	go test -cover	.golangci.yml, go.mod

References

• ESLint Documentation
• Ruff Documentation
• golangci-lint Documentation
• MegaLinter Documentation
• jscpd Documentation
• Lizard Documentation
• SARIF v2.1.0 Specification
• OWASP Top 10