cairo-l1-l2-messaging

name	cairo-l1-l2-messaging
description	Explain Starknet L1 and L2 messaging, l1_handler functions, and message syscalls; use when a request involves cross layer messaging in Cairo.

Cairo L1-L2 Messaging

Overview

Explain how messages flow between L1 and L2 and the contract patterns to send and receive them.

Quick Use

• Read references/l1-l2-messaging.md before answering.
• Use #[l1_handler] for L1 to L2 messages.
• Use send_message_to_l1_syscall for L2 to L1 messages.

Response Checklist

• Verify the L1 sender in l1_handler entry points.
• Remember that L2 to L1 messages must be consumed on L1.
• Use felt252 arrays for payloads.

Example Requests

• "How do I receive an L1 message in Cairo?"
• "How do I send a message to L1 from a contract?"
• "What is the Starknet messaging contract on L1?"