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