majiayu000 Subagent System
When to Use
- Creating specialized subagents for task-specific work
- Delegating work to pre-configured agents
- Managing subagent tool permissions and scope
- Understanding when to use agent delegation vs. direct work
What Are Subagents?
Pre-configured AI personalities that Claude Code can delegate tasks to. Each:
- Has specific purpose and expertise area
- Uses separate context window (prevents pollution)
- Can be configured with specific tools
- Includes custom system prompt
Benefits:
- Context preservation — Each operates in own context, keeping main conversation focused
- Specialized expertise — Fine-tuned instructions for specific domains
- Reusability — Use across projects and share with team
- Flexible permissions — Different tool access levels per agent
Creating Subagents
File Locations
| Type | Location | Scope |
|---|---|---|
| Project subagents | .claude/agents/ |
Current project only |
| User subagents | ~/.claude/agents/ |
All projects |
Project-level subagents take precedence over user-level when names conflict.
File Format
Each subagent is a Markdown file with YAML frontmatter:
---
name: your-sub-agent-name
description: When this subagent should be invoked
tools: tool1, tool2, tool3 # Optional - inherits all if omitted
model: sonnet # Optional - specify model or 'inherit'
---
Your subagent's system prompt goes here. Multiple paragraphs.
Include role, capabilities, approach, best practices, constraints.
Configuration Fields
| Field | Required | Description |
|---|---|---|
name |
Yes | Unique identifier (lowercase + hyphens) |
description |
Yes | Natural language purpose description |
tools |
No | Comma-separated tools (inherits all if omitted) |
model |
No | Model alias (sonnet, opus, haiku) or 'inherit' |
Using Subagents Effectively
Automatic Delegation
Claude Code proactively delegates based on:
- Task description in your request
descriptionfield in subagent configuration- Current context and available tools
To encourage proactive use, include "use PROACTIVELY" or "MUST BE USED" in description.
Explicit Invocation
Request specific subagents by name:
> Use the test-runner subagent to fix failing tests
> Have the code-reviewer subagent look at my recent changes
Management
Using /agents Command (Recommended)
Interactive menu for:
- View all available subagents
- Create new subagents with guided setup
- Edit existing custom subagents
- Delete custom subagents
- Manage tool permissions
Direct File Management
mkdir -p .claude/agents
cat > .claude/agents/test-runner.md << 'EOF'
---
name: test-runner
description: Use proactively to run tests and fix failures
---
You are a test automation expert. When you see code changes, proactively run the appropriate tests. If tests fail, analyze failures and fix them.
EOF
Best Practices
- Start with Claude-generated agents, then customize
- Design focused subagents with single, clear responsibility
- Write detailed prompts with specific instructions, examples, constraints
- Limit tool access to only necessary tools
- Version control project subagents for team collaboration
Performance Notes
- Context efficiency: Agents preserve main context, enabling longer sessions
- Latency: Subagents start with clean slate, may add latency gathering context