claude-extensibility

Q: How do I install claude-extensibility?

Run npx skills add https://github.com/samhvw8/dot-claude --skill claude-extensibility in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/claude-extensibility/ (personal) or .claude/skills/claude-extensibility/ (project).

Q: Which AI agents can use claude-extensibility?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Q: Is claude-extensibility safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Q: Who maintains claude-extensibility?

It is published by samhvw8 in samhvw8/dot-claude. It has 60 recorded installs.

by samhvw8AI & Agents

Claude Code extensibility: agents, skills, output styles. Capabilities: create/update/delete agents and skills, YAML frontmatter, system prompts, tool/model selection, resumable agents, CLI-defined agents. Actions: create, edit, delete, optimize, test extensions. Keywords: agent, skill, output-style, SKILL.md, subagent, Task tool, progressive disclosure. Use when: creating agents/skills, editing extensions, configuring tool access, choosing models, testing activation.

Installs: 60
Last 24h: —
Trending rank: —
Security: Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/samhvw8/dot-claude --skill claude-extensibility

01
Install
Run the command in your project. The CLI asks which agents to install for.
02
Describe the task
Ask your agent for something this skill covers. It loads claude-extensibility automatically when relevant.
03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Claude Code Extensibility

CRUD operations for agents, skills, and output styles following Anthropic best practices.

Related Skills

IMPORTANT: When creating or editing prompts, use prompt-enhancer skill to improve quality.

Skill("prompt-enhancer")  → Enhance skill/agent prompt content

Core Principles

Simplicity: Direct tool calls, avoid complex abstractions
Focus: Single, clear responsibility per extension
Conciseness: Target <500 lines, use progressive disclosure
Efficiency: Optimize for token usage and response time

Extension Types

Type	Invocation	Purpose	Location
Agents	Task tool	Specialized sub-processes	`.claude/agents/`
Skills	Model-invoked (autonomous)	Domain knowledge	`.claude/skills/{name}/`
Output Styles	`/output-style` command	Modify main agent behavior	`.claude/output-styles/`

Agent Development

Reference: references/agent-development.md - Full YAML structure, model/tool selection, system prompt patterns, optimization techniques.

Quick Start: Agent

---
name: agent-name
description: Use this agent when [use case]. Use PROACTIVELY for [triggers].\n\nExamples:\n<example>\nContext: [situation]\nuser: [request]\nassistant: [response]\n<commentary>[reasoning]</commentary>\n</example>
tools: Grep, Glob, Read, Bash
model: haiku
permissionMode: default
skills: skill-name
---

# Agent Name

Brief mission statement.

## Core Strategy

### 1. Phase Name
Approach and techniques

<format>
Expected output structure
</format>

YAML Fields

Field	Required	Description
`name`	Yes	Lowercase, hyphens (e.g., `code-reviewer`)
`description`	Yes	Single line with `\n` for newlines, include examples
`tools`	No	Comma-separated; inherits all if omitted
`model`	No	`haiku`, `sonnet`, `opus`, `inherit` (default: sonnet)
`permissionMode`	No	`default`, `acceptEdits`, `bypassPermissions`, `plan`, `ignore`
`skills`	No	Comma-separated skill names to auto-load

Model Selection

Model	Use When	Target Time
`haiku`	Fast tasks, exploration, search	< 3s
`sonnet`	Balanced, most use cases	< 10s
`opus`	Complex reasoning, architecture	< 30s
`inherit`	Match main conversation model	varies

Built-in Subagents

Agent	Model	Tools	Purpose
`general-purpose`	Sonnet	All	Complex research, multi-step operations
`plan`	Sonnet	Read, Glob, Grep, Bash	Research in plan mode
`Explore`	Haiku	Read-only	Fast codebase search (quick/medium/very thorough)

Agent Locations

Location	Scope	Priority
`.claude/agents/`	Project	Highest
`~/.claude/agents/`	User (all projects)	Lower
Plugin `agents/`	Plugin-specific	Varies
`--agents` CLI flag	Session only	Medium

CLI-Defined Agents

claude --agents '{
  "code-reviewer": {
    "description": "Expert code reviewer. Use proactively after code changes.",
    "prompt": "You are a senior code reviewer...",
    "tools": ["Read", "Grep", "Glob", "Bash"],
    "model": "sonnet"
  }
}'

Resumable Agents

Continue previous conversations:

Each execution gets unique agentId
Transcript stored in agent-{agentId}.jsonl
Resume with previous agentId to continue with full context

Skill Development

Reference: references/skill-development.md - Full structure, trigger patterns, hook system.

Quick Start: Skill

---
name: skill-name
description: "[What it does]. [Technologies]. Capabilities: [list]. Actions: [verbs]. Keywords: [triggers]. Use when: [scenarios]."
allowed-tools: Read, Grep, Glob
---

# Skill Name

## Purpose
What this skill helps with

## When to Use
Specific scenarios and conditions

## Key Information
Guidance, patterns, examples

YAML Fields

Field	Required	Description
`name`	Yes	Lowercase, hyphens, max 64 chars
`description`	Yes	WHAT + WHEN format, max 1024 chars, quoted
`allowed-tools`	No	Restrict tool access (security)

Description Format (WHAT + WHEN)

Structure:

"[Core purpose]. [Technologies/Stack]. Capabilities: [list]. Actions: [verbs]. Keywords: [triggers]. Use when: [scenarios]."

Good example:

description: "Extract text and tables from PDF files, fill forms, merge documents. Formats: .pdf. Tools: pypdf, pdfplumber. Capabilities: text extraction, form filling, document merging. Actions: extract, fill, merge PDFs. Keywords: PDF, form, document, pypdf, pdfplumber. Use when: working with PDF files, extracting data from documents, filling PDF forms."

Bad examples:

description: Helps with documents  # Too vague
description: PDF skill  # Missing WHEN triggers

Tool Access Control

Restrict Claude's tools with allowed-tools:

---
name: safe-reader
description: "Read-only file access. Use when viewing code without modifications."
allowed-tools: Read, Grep, Glob
---

Skill Locations

Location	Scope
`.claude/skills/{name}/SKILL.md`	Project (shared via git)
`~/.claude/skills/{name}/SKILL.md`	User (all projects)
Plugin `skills/`	Plugin-bundled

Skill Structure

my-skill/
├── SKILL.md (required)
├── references/ (optional - detailed docs)
├── scripts/ (optional - utilities)
└── templates/ (optional - templates)

Output Styles

Modify Claude Code's main agent behavior.

Quick Start: Output Style

---
name: My Custom Style
description: Brief description of behavior
keep-coding-instructions: true
---

# Custom Style Instructions

You are an interactive CLI tool that helps users...

## Specific Behaviors
[Define assistant behavior...]

YAML Fields

Field	Purpose	Default
`name`	Display name	Filename
`description`	UI description	None
`keep-coding-instructions`	Retain coding instructions	`false`

Built-in Styles

Default: Standard software engineering
Explanatory: Educational insights between tasks
Learning: Collaborative with TODO(human) markers

Output Style Locations

User: ~/.claude/output-styles/
Project: .claude/output-styles/

Usage

/output-style              # Access menu
/output-style explanatory  # Switch directly

Testing

Key Question: Does it activate when expected?

Agent Testing:

Task(
  subagent_type="agent-name",
  description="Test task",
  prompt="Detailed test prompt"
)

Skill Testing:

Test prompts that SHOULD trigger
Test prompts that should NOT trigger
Debug with: claude --debug

Common Workflows

Create Agent

Create .claude/agents/{name}.md
Write YAML frontmatter (name, description, tools, model)
Write system prompt (<500 lines)
Test with Task tool
Optimize based on performance

Create Skill

Create .claude/skills/{name}/SKILL.md
Write YAML frontmatter with WHAT + WHEN description
Write content (<500 lines)
Use Skill("prompt-enhancer") to improve prompt
Add reference files for detailed content
Test: Does it activate when expected?

Optimize Extension

Measure baseline (lines, token usage, response time)
Move details to reference files
Use Skill("prompt-enhancer") to improve prompts
Remove second-person voice
Use code blocks over prose
Add XML structure
Test and verify improvements

Best Practices

Anthropic Guidelines

✅ 500-line rule: Keep SKILL.md and agent prompts under 500 lines ✅ Progressive disclosure: Use reference files for detailed content ✅ Proactive language: Include "use PROACTIVELY" in descriptions ✅ WHAT + WHEN descriptions: Both capability and triggers ✅ Test first: Build 3+ evaluations before extensive documentation ✅ Least privilege: Limit tools to necessary set

Anti-Patterns

❌ Vague descriptions without triggers ❌ Over 500 lines without references ❌ Second-person voice ("you should...") ❌ All tools when subset suffices ❌ No examples in agent descriptions

Quick Reference

Agent Model Selection:

Haiku: Fast, simple tasks (< 3s)
Sonnet: Balanced, most use cases (< 10s)
Opus: Complex reasoning (< 30s)
Inherit: Match main conversation

File Locations:

Agents: .claude/agents/*.md
Skills: .claude/skills/{name}/SKILL.md
Output Styles: .claude/output-styles/*.md

Management Commands:

/agents - Interactive agent management
/output-style - Switch output styles

Status: Production Ready | Lines: ~200 | Progressive Disclosure: ✅

FAQ

What does the claude-extensibility skill do?

How do I install claude-extensibility?

Run npx skills add https://github.com/samhvw8/dot-claude --skill claude-extensibility in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/claude-extensibility/ (personal) or .claude/skills/claude-extensibility/ (project).

Which AI agents can use claude-extensibility?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is claude-extensibility safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains claude-extensibility?

It is published by samhvw8 in samhvw8/dot-claude. It has 60 recorded installs.

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