duplicate-finder

duplicate-finder is a skill for Claude Code from berkcangumusisik/claude-code-practices. It costs 17 tokens per session (260 once invoked), scanned A, original, MIT.

A code-review tool that searches for repeated or nearly repeated logic across a codebase and suggests ways to share it.

In plain words
What is it for?
Use it to find repeated functions, request handling, and other patterns, then review possible shared utilities, hooks, or base classes.
Why use it?
It helps reduce copy-and-paste code, so a bug fix or behavior change does not need to be made in many separate places.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to find repeated functions, request handling, and other patterns, then review possible shared utilities, hooks, or base classes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/berkcangumusisik/claude-code-practices/duplicate-finder
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.

Any agent
npx skills add berkcangumusisik/claude-code-practices --skill duplicate-finder
Clone the repo
git clone --depth 1 https://github.com/berkcangumusisik/claude-code-practices

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for duplicate-finder

README.md
[![agentmods](https://agentmods.dev/badge/skills/berkcangumusisik/claude-code-practices/duplicate-finder/github.svg)](https://agentmods.dev/skills/berkcangumusisik/claude-code-practices/duplicate-finder)
Your own site
<a href="https://agentmods.dev/skills/berkcangumusisik/claude-code-practices/duplicate-finder"><img src="https://agentmods.dev/badge/skills/berkcangumusisik/claude-code-practices/duplicate-finder/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for duplicate-finder

Your own site · 80×15
<a href="https://agentmods.dev/skills/berkcangumusisik/claude-code-practices/duplicate-finder"><img src="https://agentmods.dev/badge/skills/berkcangumusisik/claude-code-practices/duplicate-finder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 260 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00017 $0.00260
Opus 5 $0.00009 $0.00130
Sonnet 5 $0.00003 $0.00052
Haiku 4.5 $0.00002 $0.00026

Measured 9d ago against content hash a622689c3029, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

duplicate-finder 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 9d ago.

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/duplicate-finder/SKILL.md · 36 lines

What it actually says

Find Duplicate Code

  1. Look for structural duplication:
# Similar function signatures
grep -rn "async function\|const .* = async" ${1:-src}/ --include="*.ts" | sort | head -40

# Similar patterns (fetch calls, error handling, etc.)
grep -rn "try {" ${1:-src}/ --include="*.ts" -l
  1. Read suspected duplicate files side by side.

  2. Identify duplication categories:

    • Identical blocks: copy-pasted code
    • Near-duplicates: same logic, different variable names
    • Structural similarity: same pattern, different implementations
  3. For each duplication cluster:

    • Show the duplicated sections
    • Propose a shared abstraction (utility function, custom hook, base class)
    • Show how call sites would look after extraction
  4. Ask which ones to consolidate, then apply.

Focus on impactful duplications (3+ occurrences or > 20 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. 9d ago First seen · 36 lines · 17 tokens per session scan A a622689c3029

Subscribe to this mod's changes

duplicate-finder is a skill published in the GitHub repository berkcangumusisik/claude-code-practices (10 stars, last pushed 4mo ago), licensed MIT. It adds 17 tokens to every session and 260 once invoked, about $0.0001 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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