Code Complexity Analyzer

Measure cyclomatic complexity, cognitive complexity, and structural metrics for Python, JavaScript/TypeScript, and Go code. Use when analyzing code quality, finding complex functions, setting CI quality gates, reviewing code for refactoring candidates, or generating complexity reports. Supports per-function metrics, configurable thresholds, risk levels, and multiple output formats (text, JSON, markdown).

Measure cyclomatic, cognitive, and structural complexity per function. Pure Python, no dependencies.

Quick Start

# Analyze a directory
python3 scripts/analyze_complexity.py src/

# Analyze specific files
python3 scripts/analyze_complexity.py app.py utils.py

# Show all functions (not just violations)
python3 scripts/analyze_complexity.py src/ --verbose

# Custom thresholds
python3 scripts/analyze_complexity.py src/ --cc 15 --cog 20 --max-lines 80

Output Formats

python3 scripts/analyze_complexity.py src/ --format text      # human-readable (default)
python3 scripts/analyze_complexity.py src/ --format json       # CI/tooling
python3 scripts/analyze_complexity.py src/ --format markdown   # reports

Supported Languages

• Python (.py)
• JavaScript (.js, .jsx, .mjs, .cjs)
• TypeScript (.ts, .tsx)
• Go (.go)

Metrics

Metric	Description	Default Threshold
Cyclomatic (CC)	Independent execution paths	≤10
Cognitive (COG)	Perceived difficulty to understand (nesting-weighted)	≤15
Lines	Function length	≤50
Params	Parameter count	≤5
Nesting	Max nesting depth	≤4

Risk Levels

• 🟢 Simple — CC≤5, COG≤8
• 🟡 Low — CC≤10, COG≤15
• 🟠 Moderate — CC≤20, COG≤25
• 🔴 High — CC>20 or COG>25

Options

--cc N           Cyclomatic threshold (default: 10)
--cog N          Cognitive threshold (default: 15)
--max-lines N    Function length threshold (default: 50)
--max-params N   Parameter count threshold (default: 5)
--max-nesting N  Nesting depth threshold (default: 4)
--exclude DIR    Additional directories to exclude
--verbose, -v    Show all functions, not just violations

Auto-excluded: node_modules, .git, __pycache__, venv, dist, build.

Exit Codes

• 0 — no violations
• 1 — violations found (functions exceed CC or COG thresholds)
• 2 — no analyzable files found