# Cairo Ownership

> Explain Cairo ownership, moves, Copy/Drop/Destruct traits, and scope-based destruction; use when a request involves use-after-move errors, copying values, or ownership semantics in Cairo.

- Skill: `teddyjfpender/cairo-ownership` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add teddyjfpender/cairo-ownership`
- Raw SKILL.md: https://api.skillmd.com/api/skills/teddyjfpender/cairo-ownership/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: teddyjfpender (https://skillmd.com/u/teddyjfpender)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/teddyjfpender/cairo-ownership

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# Cairo Ownership

## Overview
Guide Cairo's ownership rules, move semantics, and destruction traits so code compiles without ownership errors.

## Quick Use
- Read `references/ownership.md` before answering.
- Identify whether the type is moved, copied, dropped, or destructed.
- Provide small examples showing the move or copy that fixes the error.

## Response Checklist
- State the three ownership rules and apply them to the failing line.
- If a value is used after move, suggest borrowing (snapshot/ref) or copying (Copy trait).
- Mention Drop vs Destruct when dictionaries or resource-like types are involved.

## Example Requests
- "Why is this variable unavailable after I pass it to a function?"
- "How do I make my struct Copy?"
- "Why can't I derive Drop for a struct containing a dictionary?"

## Cairo by Example
- [Scoping rules](https://cairo-by-example.xyz/scope)
- [RAII](https://cairo-by-example.xyz/scope/raii)
- [Ownership and moves](https://cairo-by-example.xyz/scope/move)
- [Mutability](https://cairo-by-example.xyz/scope/move/mut)
- [Drop and Destruct](https://cairo-by-example.xyz/trait/drop)