finding-duplicate-functions

finding-duplicate-functions is a skill for Claude Code, Codex from obra/superpowers-lab. It costs 49 tokens per session (1,059 once invoked), scanned A, original, MIT.

A code-review process for finding different functions that perform the same job, even when their names and implementations differ.

In plain words
What is it for?
Use it to extract functions, group them by purpose, compare implementations, and produce a report of consolidation opportunities.
Why use it?
It reveals semantic duplicates that ordinary copy-and-paste detectors may miss, which can otherwise leave several versions of the same utility in a codebase.

Skill for Claude CodeCodex

Part of the superpowers-lab plugin — 4 skills shipped together

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/obra/superpowers-lab/finding-duplicate-functions
Any agent
npx skills add obra/superpowers-lab --skill finding-duplicate-functions
Clone the repo
git clone --depth 1 https://github.com/obra/superpowers-lab

Made for: Claude Code, Codex.

Or install superpowers-lab, the plugin that ships this one along with the rest of its 4 skills.

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 finding-duplicate-functions

README.md
[![agentmods](https://agentmods.dev/badge/skills/obra/superpowers-lab/finding-duplicate-functions.svg)](https://agentmods.dev/skills/obra/superpowers-lab/finding-duplicate-functions)
Your own site
<a href="https://agentmods.dev/skills/obra/superpowers-lab/finding-duplicate-functions"><img src="https://agentmods.dev/badge/skills/obra/superpowers-lab/finding-duplicate-functions.svg" alt="Measured on agentmods" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,059 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 $0.00049 $0.01059
Opus 5 $0.00024 $0.00530
Sonnet 5 $0.00010 $0.00212
Haiku 4.5 $0.00005 $0.00106

Measured 4d ago against content hash fa3782c9d7e5, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

finding-duplicate-functions 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 4d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/extract-functions.sh, scripts/generate-report.sh, scripts/prepare-category-analysis.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/finding-duplicate-functions/SKILL.md · 122 lines

How it starts

The opening of the file, as written. The whole thing — 122 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Finding Duplicate-Intent Functions

Overview

LLM-generated codebases accumulate semantic duplicates: functions that serve the same purpose but were implemented independently. Classical copy-paste detectors (jscpd) find syntactic duplicates but miss "same intent, different implementation."

This skill uses a two-phase approach: classical extraction followed by LLM-powered intent clustering.

When to Use

  • Codebase has grown organically with multiple contributors (human or LLM)
  • You suspect utility functions have been reimplemented multiple times
  • Before major refactoring to identify consolidation opportunities
  • After jscpd has been run and syntactic duplicates are already handled

Quick Reference

Phase Tool Model Output
1. Extract scripts/extract-functions.sh - catalog.json
2. Categorize scripts/categorize-prompt.md haiku categorized.json
3. Split scripts/prepare-category-analysis.sh - categories/*.json
4. Detect scripts/find-duplicates-prompt.md opus duplicates/*.json
5. Report scripts/generate-report.sh - report.md

Process

digraph duplicate_detection {
  rankdir=TB;
  node [shape=box];

  extract [label="1. Extract function catalog\n./scripts/extract-functions.sh"];
  categorize [label="2. Categorize by domain\n(haiku subagent)"];
  split [label="3. Split into categories\n./scripts/prepare-category-analysis.sh"];
  detect [label="4. Find duplicates per category\n(opus subagent per category)"];
  report [label="5. Generate report\n./scripts/generate-report.sh"];
  review [label="6. Human review & consolidate"];

  extract -> categorize -> split -> detect -> report -> review;
}

Phase 1: Extract Function Catalog

./scripts/extract-functions.sh src/ -o catalog.json

Options:

  • -o FILE: Output file (default: stdout)
  • -c N: Lines of context to capture (default: 15)
  • -t GLOB: File types (default: *.ts,*.tsx,*.js,*.jsx)
  • --include-tests: Include test files (excluded by default)

Read the full file on GitHub · 122 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 4d ago First seen · 122 lines · 49 tokens per session scan A fa3782c9d7e5

Subscribe to this mod's changes

finding-duplicate-functions is a skill published in the GitHub repository obra/superpowers-lab (423 stars, last pushed 3mo ago), licensed MIT. It adds 49 tokens to every session and 1,059 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 2026-08-30.

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