Spawn Swarm

Parallel agents for parallel work.

The Pattern

Single message → Multiple Task calls → Parallel execution → Collected results

One message with 5-20 Task tool invocations. All run simultaneously. Results come back together.

Swarm Templates

Bug Hunt (5-10 agents)

"Find bugs across the codebase"

Spawn per module:

• auth-agent
• payment-agent
• user-agent
• api-agent
• data-agent

PR Review (3-4 agents)

"Review PR #123"

Spawn specialists:

• security-reviewer
• performance-reviewer
• style-reviewer
• test-coverage-reviewer

Feature Build (4 agents)

"Build [feature]"

Spawn workers:

• ui-agent
• logic-agent
• test-agent
• docs-agent

Codebase Exploration (5 agents)

"Understand how [thing] works"

Spawn explorers:

• entry-point-finder
• flow-tracer
• dependency-mapper
• pattern-identifier
• edge-case-hunter

Invocation

Single Message, Multiple Tasks

[Task: Search auth/ for security issues] [Task: Search payment/ for security issues] [Task: Search api/ for security issues] [Task: Search data/ for security issues] [Task: Search user/ for security issues]

All in ONE message.

Use run_in_background

For long-running work: run_in_background: true

Continue other work. Check results with TaskOutput later.

Agent Types

Explore (subagent_type: Explore)

Fast file/code search Pattern finding Codebase questions

General (subagent_type: general-purpose)

Multi-step implementation Complex changes Autonomous work

Specialists

code-reviewer debugger security-reviewer performance-reviewer

Sizing Guidelines

Task Agents Why

Small search 3-5 Quick coverage

Full codebase 5-10 One per major area

Deep analysis 10-15 Thorough exploration

Massive refactor 15-20 Maximum parallelism

Token Efficiency

Agents Have Narrow Context

Main conversation: Full codebase Each agent: Only its target area

5 agents searching 5 areas:

• Same tokens as 1 agent doing all 5
• 5x faster
• Each has focused context

Agent Summary Pattern

Agent explores extensively. Returns: "Found issue in auth.swift:142"

You get 1-line summary. Not the full exploration trace.

Anti-Patterns

❌ Don't

• Spawn for simple reads (just use Read tool)
• Spawn with dependencies (race conditions)
• Spawn 50 agents (chaos)
• Wait on each before spawning next

✓ Do

• One message, all agents
• Independent targets
• 5-20 agents max
• Background for long work

Example Prompt

Spawn a bug-hunting swarm:

1. Search src/auth/ for security vulnerabilities
2. Search src/payment/ for data handling issues
3. Search src/api/ for input validation bugs
4. Search src/user/ for permission issues
5. Search src/data/ for race conditions

Return findings ranked by severity.

Use when: Any parallel work opportunity