Plugin Structure for Claude Code

Overview

Claude Code plugins follow a standardized directory structure with automatic component discovery. Understanding this structure enables creating well-organized, maintainable plugins that integrate seamlessly with Claude Code.

Key concepts:

Conventional directory layout for automatic discovery

Manifest-driven configuration in

.claude-plugin/plugin.json

Component-based organization (commands, agents, skills, hooks)

Portable path references using

${CLAUDE_PLUGIN_ROOT}

Explicit vs. auto-discovered component loading

Directory Structure

Every Claude Code plugin follows this organizational pattern:

plugin-name/

├── .claude-plugin/

│ └── plugin.json # Required: Plugin manifest

├── commands/ # Slash commands (.md files)

├── agents/ # Subagent definitions (.md files)

├── skills/ # Agent skills (subdirectories)

│ └── skill-name/

│ └── SKILL.md # Required for each skill

├── hooks/

│ └── hooks.json # Event handler configuration

├── .mcp.json # MCP server definitions

└── scripts/ # Helper scripts and utilities

Critical rules:

Manifest location

The

plugin.json

manifest MUST be in

.claude-plugin/

directory

Component locations

All component directories (commands, agents, skills, hooks) MUST be at plugin root level, NOT nested inside

.claude-plugin/

Optional components

Only create directories for components the plugin actually uses

Naming convention

Use kebab-case for all directory and file names

Plugin Manifest (plugin.json)

The manifest defines plugin metadata and configuration. Located at

.claude-plugin/plugin.json

:

Required Fields

{

"name"

:

"plugin-name"

}

Name requirements:

Use kebab-case format (lowercase with hyphens)

Must be unique across installed plugins

No spaces or special characters

Example:

code-review-assistant

,

test-runner

,

api-docs

Recommended Metadata

{

"name"

:

"plugin-name"

,

"version"

:

"1.0.0"

,

"description"

:

"Brief explanation of plugin purpose"

,

"author"

:

{

"name"

:

"Author Name"

,

"email"

:

"author@example.com"

,

"url"

:

"https://example.com"

}

,

"homepage"

:

"https://docs.example.com"

,

"repository"

:

"https://github.com/user/plugin-name"

,

"license"

:

"MIT"

,

"keywords"

:

[

"testing"

,

"automation"

,

"ci-cd"

]

}

Version format

Follow semantic versioning (MAJOR.MINOR.PATCH)

Keywords

Use for plugin discovery and categorization

Component Path Configuration

Specify custom paths for components (supplements default directories):

{

"name"

:

"plugin-name"

,

"commands"

:

"./custom-commands"

,

"agents"

:

[

"./agents"

,

"./specialized-agents"

]

,

"hooks"

:

"./config/hooks.json"

,

"mcpServers"

:

"./.mcp.json"

}

Important

Custom paths supplement defaults—they don't replace them. Components in both default directories and custom paths will load.

Path rules:

Must be relative to plugin root

Must start with

./

Cannot use absolute paths

Support arrays for multiple locations

Component Organization

Commands

Location

:

commands/

directory

Format

Markdown files with YAML frontmatter

Auto-discovery

All .md files in commands/ load automatically Example structure : commands/ ├── review.md # /review command ├── test.md # /test command └── deploy.md # /deploy command File format :

name : command - name description : Command description

Command implementation instructions...

Usage

Commands integrate as native slash commands in Claude Code

Agents

Location

:

agents/

directory

Format

Markdown files with YAML frontmatter

Auto-discovery

All .md files in agents/ load automatically Example structure : agents/ ├── code-reviewer.md ├── test-generator.md └── refactorer.md File format :

description : Agent role and expertise capabilities : - Specific task 1 - Specific task 2

Detailed agent instructions and knowledge...

Usage

Users can invoke agents manually, or Claude Code selects them automatically based on task context

Skills

Location

:

skills/

directory with subdirectories per skill

Format

Each skill in its own directory with

SKILL.md

file

Auto-discovery

All SKILL.md files in skill subdirectories load automatically Example structure : skills/ ├── api-testing/ │ ├── SKILL.md │ ├── scripts/ │ │ └── test-runner.py │ └── references/ │ └── api-spec.md └── database-migrations/ ├── SKILL.md └── examples/ └── migration-template.sql SKILL.md format :

name : Skill Name description : When to use this skill version : 1.0.0

Skill instructions and guidance...

Supporting files

Skills can include scripts, references, examples, or assets in subdirectories

Usage

Claude Code autonomously activates skills based on task context matching the description

Hooks

Location

:

hooks/hooks.json

or inline in

plugin.json

Format

JSON configuration defining event handlers

Registration

Hooks register automatically when plugin enables

Example structure

:

hooks/

├── hooks.json # Hook configuration

└── scripts/

├── validate.sh # Hook script

└── check-style.sh # Hook script

Configuration format

:

{

"PreToolUse"

:

[

{

"matcher"

:

"Write|Edit"

,

"hooks"

:

[

{

"type"

:

"command"

,

"command"

:

"bash ${CLAUDE_PLUGIN_ROOT}/hooks/scripts/validate.sh"

,

"timeout"

:

30

}

]

}

]

}

Available events

PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification

Usage

Hooks execute automatically in response to Claude Code events

MCP Servers

Location

:

.mcp.json

at plugin root or inline in

plugin.json

Format

JSON configuration for MCP server definitions

Auto-start

Servers start automatically when plugin enables

Example format

:

{

"mcpServers"

:

{

"server-name"

:

{

"command"

:

"node"

,

"args"

:

[

"${CLAUDE_PLUGIN_ROOT}/servers/server.js"

]

,

"env"

:

{

"API_KEY"

:

"${API_KEY}"

}

}

}

}

Usage

MCP servers integrate seamlessly with Claude Code's tool system

Portable Path References

${CLAUDE_PLUGIN_ROOT}

Use

${CLAUDE_PLUGIN_ROOT}

environment variable for all intra-plugin path references:

{

"command"

:

"bash ${CLAUDE_PLUGIN_ROOT}/scripts/run.sh"

}

Why it matters

Plugins install in different locations depending on: User installation method (marketplace, local, npm) Operating system conventions User preferences Where to use it : Hook command paths MCP server command arguments Script execution references Resource file paths Never use : Hardcoded absolute paths ( /Users/name/plugins/... ) Relative paths from working directory ( ./scripts/... in commands) Home directory shortcuts ( ~/plugins/... ) Path Resolution Rules In manifest JSON fields (hooks, MCP servers): "command" : "${CLAUDE_PLUGIN_ROOT}/scripts/tool.sh" In component files (commands, agents, skills): Reference scripts at: ${CLAUDE_PLUGIN_ROOT}/scripts/helper.py In executed scripts :

!/bin/bash

${CLAUDE_PLUGIN_ROOT} available as environment variable

source

"

${CLAUDE_PLUGIN_ROOT}

/lib/common.sh"

File Naming Conventions

Component Files

Commands

Use kebab-case

.md

files

code-review.md

→

/code-review

run-tests.md

→

/run-tests

api-docs.md

→

/api-docs

Agents

Use kebab-case

.md

files describing role

test-generator.md

code-reviewer.md

performance-analyzer.md

Skills

Use kebab-case directory names

api-testing/

database-migrations/

error-handling/

Supporting Files

Scripts

Use descriptive kebab-case names with appropriate extensions

validate-input.sh

generate-report.py

process-data.js

Documentation

Use kebab-case markdown files

api-reference.md

migration-guide.md

best-practices.md

Configuration

Use standard names

hooks.json

.mcp.json

plugin.json

Auto-Discovery Mechanism

Claude Code automatically discovers and loads components:

Plugin manifest

Reads

.claude-plugin/plugin.json

when plugin enables

Commands

Scans

commands/

directory for

.md

files

Agents

Scans

agents/

directory for

.md

files

Skills

Scans

skills/

for subdirectories containing

SKILL.md

Hooks

Loads configuration from

hooks/hooks.json

or manifest

MCP servers

Loads configuration from

.mcp.json

or manifest

Discovery timing

:

Plugin installation: Components register with Claude Code

Plugin enable: Components become available for use

No restart required: Changes take effect on next Claude Code session

Override behavior

Custom paths in

plugin.json

supplement (not replace) default directories

Best Practices

Organization

Logical grouping

Group related components together

Put test-related commands, agents, and skills together

Create subdirectories in

scripts/

for different purposes

Minimal manifest

Keep

plugin.json

lean

Only specify custom paths when necessary

Rely on auto-discovery for standard layouts

Use inline configuration only for simple cases

Documentation

Include README files

Plugin root: Overall purpose and usage

Component directories: Specific guidance

Script directories: Usage and requirements

Naming

Consistency

Use consistent naming across components

If command is

test-runner

, name related agent

test-runner-agent

Match skill directory names to their purpose

Clarity

Use descriptive names that indicate purpose

Good:

api-integration-testing/

,

code-quality-checker.md

Avoid:

utils/

,

misc.md

,

temp.sh

Length

Balance brevity with clarity

Commands: 2-3 words (

review-pr

,

run-ci

)

Agents: Describe role clearly (

code-reviewer

,

test-generator

)

Skills: Topic-focused (

error-handling

,

api-design

)

Portability

Always use ${CLAUDE_PLUGIN_ROOT}

Never hardcode paths

Test on multiple systems

Verify on macOS, Linux, Windows

Document dependencies

List required tools and versions

Avoid system-specific features

Use portable bash/Python constructs

Maintenance

Version consistently

Update version in plugin.json for releases

Deprecate gracefully

Mark old components clearly before removal

Document breaking changes

Note changes affecting existing users

Test thoroughly

Verify all components work after changes Common Patterns Minimal Plugin Single command with no dependencies: my-plugin/ ├── .claude-plugin/ │ └── plugin.json # Just name field └── commands/ └── hello.md # Single command Full-Featured Plugin Complete plugin with all component types: my-plugin/ ├── .claude-plugin/ │ └── plugin.json ├── commands/ # User-facing commands ├── agents/ # Specialized subagents ├── skills/ # Auto-activating skills ├── hooks/ # Event handlers │ ├── hooks.json │ └── scripts/ ├── .mcp.json # External integrations └── scripts/ # Shared utilities Skill-Focused Plugin Plugin providing only skills: my-plugin/ ├── .claude-plugin/ │ └── plugin.json └── skills/ ├── skill-one/ │ └── SKILL.md └── skill-two/ └── SKILL.md Troubleshooting Component not loading : Verify file is in correct directory with correct extension Check YAML frontmatter syntax (commands, agents, skills) Ensure skill has SKILL.md (not README.md or other name) Confirm plugin is enabled in Claude Code settings Path resolution errors : Replace all hardcoded paths with ${CLAUDE_PLUGIN_ROOT} Verify paths are relative and start with ./ in manifest Check that referenced files exist at specified paths Test with echo $CLAUDE_PLUGIN_ROOT in hook scripts Auto-discovery not working : Confirm directories are at plugin root (not in .claude-plugin/ ) Check file naming follows conventions (kebab-case, correct extensions) Verify custom paths in manifest are correct Restart Claude Code to reload plugin configuration Conflicts between plugins : Use unique, descriptive component names Namespace commands with plugin name if needed Document potential conflicts in plugin README Consider command prefixes for related functionality For detailed examples and advanced patterns, see files in references/ and examples/ directories.