fallow

name: fallow description: Analyzes TypeScript and JavaScript codebases for dead code, duplication, complexity, and architectural hotspots. Use when the user asks to run a codebase audit, find unused code or dependencies, detect duplicate code, check health scores, or when reviewing pull request risk.

Fallow is a deterministic codebase intelligence engine for TypeScript and JavaScript. It provides structured evidence for codebase quality, dead code, duplication, and architecture.

Quick start

Run a changed-code audit (useful for PRs):

npx fallow audit --format json

Check project health and complexity:

npx fallow health --score --hotspots --targets

Workflows

1. Cleanup Opportunities (Dead Code)

Find unused files, exports, dependencies, types, and stale suppressions.

npx fallow dead-code
# Options:
# --unused-exports         Only unused exports
# --circular-deps          Only circular dependencies
# --boundary-violations    Only boundary violations

2. Duplication Detection

Find copy-pasted or structurally identical code blocks.

npx fallow dupes
# Options:
# --mode semantic          Catch clones with renamed variables
# --trace <file:line>      Show all clones of code at this location

3. Complexity & Refactoring Targets

Surface the most complex functions and refactoring targets.

npx fallow health
# Options:
# --top 20                 20 most complex functions
# --hotspots               Riskiest files (git churn x complexity)
# --targets                Ranked refactoring recommendations

4. Agent Workflows

Always use --format json when parsing output programmatically or reading it as an agent. The JSON output includes per-issue actions with an auto_fixable flag.

npx fallow audit --format json

To preview automatic cleanup:

npx fallow fix --dry-run --format json