detecting-dead-code

A code-cleanup skill that finds code, files, settings, and packages no longer used by a project. It sorts findings by how safe they are to remove, including code that may be loaded dynamically or used in other builds.

In plain words
What is it for?
Use it before refactoring, while reducing project size, when investigating slow builds, or when checking for unused exports, orphaned files, configuration, and dependencies.
Why use it?
Unused code makes projects larger and harder to understand, and can slow builds. The classifications help separate safe removals from items that need checking first.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/quangphu1912/codebase-analyzer/detecting-dead-code
Any agent
npx skills add quangphu1912/codebase-analyzer --skill detecting-dead-code
Clone the repo
git clone --depth 1 https://github.com/quangphu1912/codebase-analyzer

Made for: Claude Code, Codex.

Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 832 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00032 $0.00832
Opus 5 $0.00016 $0.00416
Sonnet 5 $0.00006 $0.00166
Haiku 4.5 $0.00003 $0.00083

Measured yesterday against content hash 332a1a109dd2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

detecting-dead-code scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/detecting-dead-code/SKILL.md · 89 lines

How it starts

The opening of the file, as written. The whole thing — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Announce at start: "Using codebase-analyzer to detect dead code."

Overview

Find code that is unreachable, unused, or orphaned. Classify findings by removal safety.

Process

  1. Find unused exports: symbols exported but never imported elsewhere
  2. Find unreachable code: after return/throw, behind false conditions
  3. Find orphaned files: files not imported/required by anything
  4. Find dead config: config keys no code reads
  5. Find unused dependencies in package manifests
  6. Classify: safe-to-remove, needs-verification, keep-for-compat

Classification

Category Confidence Action
Exported, nothing imports it HIGH safe Remove
Behind false compile condition HIGH safe Remove
Not imported but may be dynamic MEDIUM verify Check dynamic imports
Platform-conditional code LOW verify May be alive in other builds
Public API for external use KEEP Document if missing

Trigger Signals

  • HIGH confidence: Code dead in THIS build but build flags suggest alive in other configs -> map-feature-gates
  • HIGH confidence: Significant dead code behind feature flags -> analyze-build-pipeline
  • MEDIUM confidence: Dead code that was recently killed -> analyze-agent-loop (check git history)
  • LOW confidence: Standard unused code -> refactoring candidate only

Warning: False Positives

Dynamic imports, reflection, plugin systems, and eval() can make live code appear dead. Always check for these before reporting.

Dead Code Archaeology

Before removing anything, determine why code died. Use git log -p -- <file> to investigate. The story matters more than the fact of death.

Pattern Meaning Action
Behind feature flag Upcoming, not dead (not yet released) Keep, check flag status
Recently deleted Changed requirement Verify removal was intentional
Commented out Broken migration, someone couldn't finish Check linked tickets/PRs
Conditionally excluded Configuration-dependent May be alive in other builds

Read the full file on GitHub · 89 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 89 lines · 32 tokens per session scan A 332a1a109dd2

Subscribe to this mod's changes

detecting-dead-code is a skill published in the GitHub repository quangphu1912/codebase-analyzer (2 stars, last pushed 4mo ago), licensed MIT. It adds 32 tokens to every session and 832 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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