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Analyze function complexity across your codebase. Fallow computes cyclomatic and cognitive complexity for every function, then reports those exceeding configurable thresholds.
Use --top N to quickly find the most complex functions without setting thresholds.
fallow health

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Options

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Thresholds

FlagDescription
--max-cyclomatic <N>Maximum cyclomatic complexity before reporting (default: 20)
--max-cognitive <N>Maximum cognitive complexity before reporting (default: 15)

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Output

FlagDescription
-f, --format <FORMAT>Output format: human (default), json, compact
--top <N>Show only the top N most complex functions
--sort <METRIC>Sort by: cyclomatic (default), cognitive, lines

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Exit codes

CodeMeaning
0No functions exceed the configured thresholds
1One or more functions exceed a threshold

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Examples

# Report functions exceeding default thresholds
fallow health

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Example output

$ fallow health --top 5
  1. src/server/resolvers/analytics.ts:42  processAnalytics
     cyclomatic: 34  cognitive: 28  lines: 187

  2. src/features/auth/handlers.ts:118  handleOAuthCallback
     cyclomatic: 27  cognitive: 22  lines: 134

  3. src/utils/parser.ts:15  parseExpression
     cyclomatic: 25  cognitive: 31  lines: 98

  4. src/server/middleware/validate.ts:8  validateRequest
     cyclomatic: 22  cognitive: 18  lines: 76

  5. src/components/Table/Table.tsx:44  renderColumns
     cyclomatic: 21  cognitive: 16  lines: 112

5 functions exceed thresholds (0.14s)

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JSON output

$ fallow health --format json --top 2
{
  "functions": [
    {
      "file": "src/server/resolvers/analytics.ts",
      "line": 42,
      "name": "processAnalytics",
      "cyclomatic": 34,
      "cognitive": 28,
      "lines": 187
    },
    {
      "file": "src/features/auth/handlers.ts",
      "line": 118,
      "name": "handleOAuthCallback",
      "cyclomatic": 27,
      "cognitive": 22,
      "lines": 134
    }
  ],
  "summary": {
    "functions_analyzed": 1842,
    "functions_exceeding": 2
  }
}

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Configuration

Configure default thresholds and ignore patterns in your config file: 
{
  "health": {
    "maxCyclomatic": 20,
    "maxCognitive": 15,
    "ignore": ["**/*.generated.ts", "src/legacy/**"]
  }
}
See Configuration for the full config reference.

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See also

Dead code analysis

Find unused code alongside complexity hotspots.

Configuration

Set default thresholds in your config file.

CI integration

Enforce complexity limits in your pipeline.