find-duplicate-ownership

find-duplicate-ownership is a skill for Codex from instructa/agent-skills. It costs 99 tokens per session (1,064 once invoked), scanned A, original, no licence file.

An architecture review tool for finding places where the same rule or data is controlled in more than one part of a codebase. It also looks for mismatches between layers, such as validation, storage, caching, and runtime state.

In plain words
What is it for?
Use it when reviewing normalization, validation, defaults, canonical data, persistence mappings, runtime state, query or cache ownership, or any question about which part of the system owns a rule.
Why use it?
Duplicate sources of truth can make a change behave differently depending on which code path uses it. Finding the owner of each rule helps prevent inconsistent behavior and contract drift.

Skill for Codex

Written for Codex: agents/openai.yaml present.

Good fit Use it when reviewing normalization, validation, defaults, canonical data, persistence mappings, runtime state, query or cache ownership, or any question about which part of the system owns a rule.

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Install with agentmods
npx agentmods add skills/instructa/agent-skills/find-duplicate-ownership
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 instructa/agent-skills --skill find-duplicate-ownership
Clone the repo
git clone --depth 1 https://github.com/instructa/agent-skills

Made for: Codex.

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 find-duplicate-ownership

README.md
[![agentmods](https://agentmods.dev/badge/skills/instructa/agent-skills/find-duplicate-ownership/github.svg)](https://agentmods.dev/skills/instructa/agent-skills/find-duplicate-ownership)
Your own site
<a href="https://agentmods.dev/skills/instructa/agent-skills/find-duplicate-ownership"><img src="https://agentmods.dev/badge/skills/instructa/agent-skills/find-duplicate-ownership/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 find-duplicate-ownership

Your own site · 80×15
<a href="https://agentmods.dev/skills/instructa/agent-skills/find-duplicate-ownership"><img src="https://agentmods.dev/badge/skills/instructa/agent-skills/find-duplicate-ownership.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 99 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,064 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 unknown 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 $0.00099 $0.01064
Opus 5 $0.00049 $0.00532
Sonnet 5 $0.00020 $0.00213
Haiku 4.5 $0.00010 $0.00106

Measured 9d ago against content hash 9f404d69f758, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

find-duplicate-ownership 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/engineering/find-duplicate-ownership/SKILL.md · 121 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

6 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. 9d ago First seen · 121 lines · 99 tokens per session scan A 9f404d69f758

Subscribe to this mod's changes

find-duplicate-ownership is a skill published in the GitHub repository instructa/agent-skills (141 stars, last pushed 19d ago), with no licence file. It adds 99 tokens to every session and 1,064 once invoked, about $0.0005 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.