Agent skill
subagents-creator
Guide for creating Claude Code subagents (custom agents) - specialized AI assistants with isolated context. Use when the user wants to create, add, or configure a subagent/custom agent for Claude Code.
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Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/development/subagents-creator
SKILL.md
Subagents Creator
Create Claude Code subagents - specialized AI assistants that run in isolated context windows.
What Subagents Provide
| Benefit | Description |
|---|---|
| Context Isolation | Each subagent has its own context, preventing main conversation pollution |
| Specialized Expertise | Fine-tuned instructions for specific domains |
| Reusability | Use across projects, share with team |
| Flexible Permissions | Different tool access per subagent |
| Parallelization | Multiple subagents can run concurrently |
Workflow
Step 1: Determine Subagent Requirements
Ask the user:
- What should this subagent do? (its specialty/purpose)
- What tools does it need? (see Available Tools below)
- When should it be triggered? (automatic vs explicit invocation)
Step 2: Determine Installation Scope
Ask where to install the subagent:
| Scope | Path | Use Case |
|---|---|---|
| Project | .claude/agents/ |
Team-shared, committed to git |
| User global | ~/.claude/agents/ |
Personal agents for all projects |
| User profile | ~/.claude-<profile>/agents/ |
Profile-specific agents |
For user-level agents, ask which profile or if using default ~/.claude/.
Step 3: Create the Subagent
File Format
Create a Markdown file with YAML frontmatter:
markdown
---
name: agent-name
description: When this agent should be invoked. Use "proactively" to encourage automatic use.
tools: Read, Grep, Glob, Bash
model: sonnet
---
Your agent's system prompt goes here. Define its role, capabilities,
approach, and any specific instructions or constraints.
Configuration Fields
| Field | Required | Description |
|---|---|---|
name |
Yes | Lowercase with hyphens (e.g., code-reviewer) |
description |
Yes | When to invoke. Include "proactively" or "MUST BE USED" to encourage automatic delegation |
tools |
No | Comma-separated list. Inherits all tools if omitted |
model |
No | sonnet, opus, haiku, or inherit. Default: sonnet |
permissionMode |
No | default, acceptEdits, bypassPermissions, plan |
skills |
No | Comma-separated skill names to auto-load |
Step 4: Write Effective Prompts
Include in the system prompt:
- Role definition - Who the agent is
- Trigger behavior - What to do when invoked
- Process/checklist - Steps to follow
- Output format - How to present results
- Constraints - What NOT to do
See references/examples.md for complete working examples.
Available Tools
Read-Only:
Read- Read file contentsGlob- File pattern matchingGrep- Content search with regex
Execution:
Bash- Shell commandsEdit- Targeted file editsWrite- Create/overwrite files
Search:
WebFetch- Fetch URL contentWebSearch- Web searches
Other:
Skill- Execute skillsSlashCommand- Run slash commands
NOT Available: Task (prevents nested agent spawning)
Built-In Subagents
| Agent | Model | Tools | Purpose |
|---|---|---|---|
| general-purpose | Sonnet | All | Complex multi-step tasks |
| Plan | Sonnet | Read, Glob, Grep, Bash (read-only) | Codebase research in plan mode |
| Explore | Haiku | Glob, Grep, Read, Bash (read-only) | Fast codebase searching |
Invocation Methods
- Automatic - Claude delegates based on task matching
description - Explicit - User mentions agent: "Use the code-reviewer agent..."
- CLI flag -
claude --agents '{...}'for session-only agents
Best Practices
- Focused purpose - Single clear responsibility per agent
- Detailed prompts - Include specific instructions, examples, constraints
- Minimal tools - Only grant necessary tools
- Action-oriented descriptions - Help Claude match tasks appropriately
- Version control - Commit project agents for team sharing
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