npm install -g fallow          # prebuilt binaries (fastest)

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npm install @fallow-cli/fallow-node

import { detectDeadCode, detectDuplication, computeHealth } from '@fallow-cli/fallow-node';

const deadCode = await detectDeadCode({ root: process.cwd(), explain: true });
const dupes = await detectDuplication({ root: process.cwd(), mode: 'mild', minTokens: 30 });
const health = await computeHealth({ root: process.cwd(), score: true, ownershipEmails: 'handle' });

fallow dead-code --format json --quiet

fallow dead-code --format json --quiet --unused-exports

fallow dead-code --format json --quiet --changed-since main --fail-on-issues

fallow dupes --format json --quiet
fallow dupes --format json --quiet --mode semantic

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The `--yes` flag is required in non-TTY environments (agent subprocesses). Without it, `fix` exits with code 2.

fallow list --entry-points --format json --quiet
fallow list --plugins --format json --quiet

fallow dead-code --format json --quiet --production

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Scopes output while keeping the full cross-workspace graph. Patterns are tested against BOTH the package name (from `package.json`) AND the workspace path relative to the repo root; either match counts. Use `!`-prefixed patterns to exclude.

`--changed-workspaces <REF>` auto-derives the set from `git diff`. It's the CI primitive: point it at the PR base branch (e.g. `origin/main`) and fallow reports only on workspaces touched by the change. Mutually exclusive with `--workspace`. A missing ref or non-git directory is a hard error (exit 2) rather than a silent full-scope fallback, so CI never quietly widens back to the whole monorepo.

fallow dead-code --format json --quiet --file src/utils.ts --file src/helpers.ts

fallow dead-code --format json --quiet --include-entry-exports

undefined

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Auto-detects `knip.json`, `.knip.json`, `.jscpd.json`, and package.json embedded configs.

fallow init              # creates .fallowrc.json, adds .fallow/ to .gitignore
fallow init --toml       # creates fallow.toml, adds .fallow/ to .gitignore
fallow init --hooks      # scaffold a pre-commit git hook
fallow init --hooks --branch develop  # hook using custom base branch

{"error": true, "message": "invalid config: ...", "exit_code": 2}

{
  "$schema": "https://raw.githubusercontent.com/fallow-rs/fallow/main/schema.json",
  "entry": ["src/index.ts"],
  "ignorePatterns": ["**/*.generated.ts"],
  "ignoreDependencies": ["autoprefixer"],
  "publicPackages": ["@myorg/shared-lib"],
  "dynamicallyLoaded": ["plugins/**/*.ts"],
  "rules": {
    "unused-files": "error",
    "unused-exports": "warn",
    "unused-types": "off"
  }
}

// fallow-ignore-next-line
export const keepThis = 1;

// fallow-ignore-next-line unused-export
export const keepThisToo = 2;

// fallow-ignore-file
// fallow-ignore-file unused-export

// Mark as intentionally unused (tracked for staleness)
/** @expected-unused */
export const deprecatedHelper = () => {};