Agent Teams

Coordinate multiple autonomous agents working on a shared task list with direct messaging.

Core principle: Teams for collaboration with shared state. Subagents for focused tasks returning results. Don't use teams when subagents suffice.

When to Use

digraph when_to_use {
    "Complex task?" [shape=diamond];
    "Independent subtasks?" [shape=diamond];
    "Need agents to communicate?" [shape=diamond];
    "Need shared task tracking?" [shape=diamond];
    "Single agent" [shape=box];
    "Subagents (Task tool)" [shape=box];
    "Agent Teams" [shape=box];

    "Complex task?" -> "Single agent" [label="no"];
    "Complex task?" -> "Independent subtasks?" [label="yes"];
    "Independent subtasks?" -> "Need agents to communicate?" [label="yes"];
    "Independent subtasks?" -> "Single agent" [label="no - sequential"];
    "Need agents to communicate?" -> "Agent Teams" [label="yes"];
    "Need agents to communicate?" -> "Need shared task tracking?" [label="no"];
    "Need shared task tracking?" -> "Agent Teams" [label="yes"];
    "Need shared task tracking?" -> "Subagents (Task tool)" [label="no - just results"];
}

Use teams:

• Cross-layer work (frontend + backend + tests) needing coordination
• Research with multiple competing hypotheses sharing findings
• PR review with parallel security/performance/tests reviewers
• Large refactoring where agents own separate modules but must align

Use subagents instead:

• Focused tasks where you only need the result
• No inter-agent communication needed
• Simple parallel dispatch (use dispatching-parallel-agents)

Teams vs Subagents

Lifecycle

1. Create Team

Teammate(operation="spawnTeam", team_name="my-feature", description="Building auth module")

Creates:

• ~/.claude/teams/my-feature/config.json — members registry
• ~/.claude/tasks/my-feature/ — shared task list

2. Create Tasks

TaskCreate(subject="Implement JWT middleware", description="...", activeForm="Implementing JWT middleware")
TaskCreate(subject="Write auth API tests", description="...", activeForm="Writing auth tests")

3. Spawn Teammates

Use Task tool with team_name and name:

Task(
    subagent_type="general-purpose",
    team_name="my-feature",
    name="backend-dev",
    prompt="You are a backend developer. Check TaskList for your assignments."
)
Task(
    subagent_type="general-purpose",
    team_name="my-feature",
    name="test-writer",
    prompt="You are a test specialist. Check TaskList for your assignments."
)

4. Assign Tasks

TaskUpdate(taskId="1", owner="backend-dev")
TaskUpdate(taskId="2", owner="test-writer")

5. Monitor & Communicate

SendMessage(type="message", recipient="backend-dev", content="Use httpOnly cookies for tokens", summary="JWT storage guidance")

Teammates auto-notify you when idle (turn ended). This is normal — idle means waiting, not done.

6. Shutdown

SendMessage(type="shutdown_request", recipient="backend-dev", content="Work complete")
SendMessage(type="shutdown_request", recipient="test-writer", content="Work complete")
# Wait for confirmations, then:
Teammate(operation="cleanup")

Best Practices

Task Sizing

• 5-6 tasks per teammate is optimal
• Too small → coordination overhead > value
• Too large → no checkpoints, hard to monitor
• Each task should have clear deliverable (file, function, test suite)

Prevent File Conflicts

Two agents editing same file = overwrites. Partition by ownership:

backend-dev  → src/auth/middleware.ts, src/auth/jwt.ts
test-writer  → tests/auth/*.test.ts

If overlap unavoidable: sequence the tasks with addBlockedBy.

Context for Teammates

Teammates DON'T inherit your conversation history. They get:

• CLAUDE.md + rules
• MCP servers, skills
• Your spawn prompt

Make spawn prompts rich:

❌ "Fix the auth bug"
✅ "Fix JWT expiry bug in src/auth/jwt.ts. Token refresh fails when
    access token expires but refresh token is valid. Error: 'TokenExpiredError'
    at line 42. The refresh logic in refreshAccessToken() doesn't check
    refresh token validity before attempting renewal. Write tests first."

Communication Patterns

Lead → Teammate: Direct message with context

SendMessage(type="message", recipient="backend-dev",
    content="The DB schema changed - users table now has 'role' column",
    summary="Schema change notification")

Broadcast (use sparingly — sends to ALL):

SendMessage(type="broadcast", content="Blocking bug found, pause work", summary="Stop all work")

Plan approval: Spawn teammate in plan mode, review their plan before they implement.

Idle State

Teammates go idle after every turn. This is normal behavior, not an error:

• Idle = waiting for input
• Sending a message wakes them up
• Don't react to idle notifications unless assigning new work

Common Mistakes

Anti-Patterns

Pipeline anti-pattern: Don't split sequential phases into separate agents (planning → implementation → testing). One agent doing all three is cheaper and avoids handoff loss.

Manager-only lead: Don't just coordinate — the lead agent should also do work. Delegate mode is for complex orchestration only.

Over-communication: Don't broadcast status updates. Use TaskUpdate to mark progress — teammates check TaskList themselves.

Quick Reference

Limitations (Current)

• No /resume for in-process teammates
• One team per session
• No nested teams (teammates can't create sub-teams)
• Lead is fixed for lifecycle
• Split panes need tmux/iTerm2 (not VS Code terminal)
• Task status may lag — teammates sometimes forget to mark completed