messaging

Messaging

Experimental: Agent teams are disabled by default. Enable with CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS in your settings.json or environment.

Send and receive messages between agents. All inter-agent communication flows through the messaging system.

Related skills:

• Orchestrating - Primitives overview and quick reference
• Team Management - Shutdown and plan approval workflows
• Task System - Coordinating task progress
• Error Handling - Debugging message issues

---

SendMessage Tool

All messaging uses the SendMessage tool. The to field specifies the recipient and the message field carries either a plain string or a structured protocol object.

Direct Message

Send a message to one specific teammate:

SendMessage({
  to: "security-reviewer",
  message: "Please prioritize the authentication module. The deadline is tomorrow.",
  summary: "Prioritize auth module review"  // 5-10 word preview shown in UI
})

Parameters:

• to - Teammate name (required)
• message - Message text (required)
• summary - Brief preview for UI (required)

IMPORTANT for teammates: Your plain text output is NOT visible to the team. You MUST use SendMessage to communicate. Just typing a response is not enough.

Broadcast

Send the same message to all teammates at once:

SendMessage({
  to: "*",
  message: "Status check: Please report your progress",
  summary: "Requesting status from all teammates"
})

WARNING: Broadcasting is expensive. Each broadcast sends N separate messages for N teammates. Costs scale linearly with team size.

When to broadcast:

• Critical issues requiring immediate team-wide attention
• Major announcements that affect everyone equally

When NOT to broadcast (use direct message instead):

• Responding to one teammate
• Normal back-and-forth communication
• Information relevant to only some teammates
• Following up on a task with one person