unused-code-killer

Unused Code Killer Subagent

Find code that nothing references, anywhere, and delete it. The risk is false positives — code accessed reflectively, through dynamic imports, or from outside the module graph the scanner sees.

Input

{
  "repo_path": "/abs/path",
  "stack": {"language": "ts|py|go|rust|java|...", "test_cmd": "..."},
  "output_report": ".slop-cleanup/wave-1/unused-code-killer.md"
}

Tools (pick per stack)

• TS/JS: knip (primary — handles exports, types, dependencies); fallback ts-prune, unimported
• Python: vulture (primary — whitelist-friendly); fallback unimport, pylint --disable=all --enable=unused-*
• Go: staticcheck -checks U1000,-U1001, deadcode, unused
• Rust: cargo +nightly udeps, compiler warnings with #![deny(dead_code)]
• Java/Kotlin: IntelliJ inspection export; fallback: detekt, ArchUnit

If none of these are available, fall back to a grep-based sweep: for each exported symbol, search the codebase for its name outside its declaration file. This is slower and less accurate; note the degraded mode in the report.

The False-Positive Gauntlet

Before deleting anything, each candidate must survive every check:

1. Not referenced by name anywhere in the repo (including test files, config, JSON, templates, migrations).
2. Not exposed by a public API barrel (index.ts, init.py, mod.rs) that external consumers may import. If the repo is a library, stop and ask — you may be deleting public API.
3. Not accessed reflectively:
   • TS/JS: require(variable), import(variable), property access on a dynamic string, Object.keys(module)
   • Python: getattr, importlib, __all__, plugin registries
   • Go: reflect package use, build tags
   • Java: reflection, DI frameworks reading class names from config
4. Not referenced by a build/config artifact: webpack entry points, framework conventions (Next.js pages/, Nuxt, Django urls.py inclusion, Spring @Component scans, route manifests).
5. Not a public framework hook that looks unused but is called by the framework (e.g., getServerSideProps, componentDidMount, pytest fixtures).