Agent Teams

Coordinate multiple Claude Code sessions working on the same codebase simultaneously.

Enable

bash
export CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1
claude  # starts as team lead

The first session becomes the team lead. Subsequent sessions in the same repo join as teammates.

Architecture

text
Team Lead (coordinates, delegates, reviews)
  ├── Teammate 1 (owns task A, messages lead + peers)
  ├── Teammate 2 (owns task B, messages lead + peers)
  └── Teammate 3 (owns task C, messages lead + peers)
      │
      └── Shared: task list + mailbox + file locks

Key difference from subagents: Teammates are full Claude Code sessions. They have their own context window, can use all tools, and message each other directly — not just report back to a parent.

Team Sizing

| Team Size | Best For | |-----------|----------| | 2 | One builds, one reviews | | 3-5 | Parallel features across layers (API, UI, tests) | | > 5 | Coordination overhead outweighs parallelism |

3-5 teammates is the productive range. Beyond that, the lead spends more time coordinating than the team saves.

Task granularity: Aim for 5-6 tasks per teammate. Fewer means underutilization; more means excessive context switching.

Display Modes

In-process navigation:

• Shift+Down — cycle through teammates (wraps around)
• See each teammate's current task and output

Split-pane (recommended for >2 teammates):

• tmux: tmux split-window -h per teammate
• iTerm2: Cmd+D for vertical split
• Each pane runs its own claude session

Task Management

Tasks flow through states:

text
pending → in-progress → completed
              │
              └── blocked (waiting on dependency)

Task Decomposition

Break work into units that:

• Touch non-overlapping files
• Can be verified independently
• Have clear done criteria

Good decomposition:

text
Task 1: Add rate limiting middleware (src/middleware/rate-limit.ts)
Task 2: Add rate limit tests (tests/rate-limit.test.ts)
Task 3: Update API docs for rate limit headers (docs/api.md)
Task 4: Add Redis config for rate limit store (src/config/redis.ts)

Bad decomposition:

text
Task 1: Implement rate limiting
Task 2: Fix rate limiting bugs
Task 3: Improve rate limiting

Dependencies

Tasks can declare dependencies:

text
Task 3 (API docs) → depends on Task 1 (middleware)
Task 2 (tests) → depends on Task 1 (middleware)
Task 4 (Redis config) → no dependencies

Teammates pick up unblocked tasks automatically.

File-Lock Claiming

Teammates claim files before editing to prevent conflicts:

1. Teammate checks if file is locked
2. If free, claims it (file-lock-based)
3. Edits the file
4. Releases lock on task completion

If two teammates need the same file, one waits or the lead reassigns.

Plan Approval

Teammates plan before implementing:

1. Teammate receives task
2. Writes a brief plan (files to change, approach)
3. Lead reviews plan
4. Lead approves or redirects
5. Teammate implements

This prevents wasted work from misunderstood requirements.

Delegate Mode

Shift+Tab toggles delegate mode for the lead:

• Lead coordinates only — no direct code edits
• All implementation delegated to teammates
• Lead reviews, approves plans, manages task flow

Hook Events

| Hook | Fires When | |------|------------| | TeammateIdle | A teammate finishes its task and has no pending work | | TaskCreated | New task added to the shared list | | TaskCompleted | A teammate marks a task done |

Use these to trigger notifications, auto-assign next tasks, or run integration tests when all tasks complete.

When to Use Teams vs Alternatives

| Scenario | Use | |----------|-----| | Parallel work on non-overlapping files | Agent teams | | Quick background exploration | Subagent | | Isolated feature branch work | Worktree (claude -w) | | Competing approaches to same problem | Worktrees (compare results) | | Cross-layer changes (API + UI + tests) | Agent teams | | One-off delegation | Subagent with isolation: worktree | | Large-scale migration (20+ files) | /batch command |

Anti-Patterns

• More than 5 teammates — coordination overhead dominates
• Tasks that share mutable state or the same files
• Skipping plan approval — leads to rework
• Lead doing implementation instead of coordinating (use delegate mode)
• Not setting dependencies — teammates race on coupled tasks

Example Session

text
Lead: "We need rate limiting. Breaking into 4 tasks."

  Task 1: middleware implementation → Teammate 1
  Task 2: Redis config → Teammate 2 (no deps)
  Task 3: tests → Teammate 1 (after Task 1)
  Task 4: API docs → Teammate 2 (after Task 1)

Teammate 1 plans → Lead approves → implements Task 1
Teammate 2 plans → Lead approves → implements Task 2
Task 1 completes → unblocks Tasks 3 and 4
Teammate 1 picks up Task 3, Teammate 2 picks up Task 4
All complete → Lead runs integration tests → commits

Docs

https://code.claude.com/docs/agent-teams