# Cairo Upgradeability

> Explain Starknet upgradeability via class hash replacement and proxy patterns; use when a request involves upgrading contract logic or replace_class_syscall.

- Skill: `teddyjfpender/cairo-upgradeability` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add teddyjfpender/cairo-upgradeability`
- Raw SKILL.md: https://api.skillmd.com/api/skills/teddyjfpender/cairo-upgradeability/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-upgradeability

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# Cairo Upgradeability

## Overview
Explain how Starknet upgrades work and the safeguards commonly used.

## Quick Use
- Read `references/upgradeability.md` before answering.
- Mention `replace_class_syscall` and access control.
- Suggest proxy patterns for more flexible upgrades.

## Response Checklist
- Use a protected upgrade entry point that validates the new class hash.
- Explain that upgrades replace the class hash of an instance.
- Note that storage is preserved across upgrades.

## Example Requests
- "How do I upgrade a Starknet contract?"
- "What does replace_class_syscall do?"
- "Why do I need access control for upgrades?"