Teammate Mailbox Messaging

What: A new messaging system allowing Claude agents to send and receive messages between teammates in multi-agent scenarios.

How it works:

• Mailbox stored at .claude/mailbox (BH5 variable at line 344469)
• Messages formatted as <teammate-message teammate_id="..."> (line 344461)
• Supports read/unread tracking with AY2() function at line 344440
• Messages delivered as attachments of type teammate_mailbox (line 345180)

Details:

• vH5() function at line 345163 checks for unread messages
• QY2() function at line 344459 formats messages for delivery
• eI2() function at line 344437 filters for unread messages only
• Evidence: New in v2.0.59 - no matches found in v2.0.58