/command-development

name: command-development
description: This skill should be used when the user asks to "create a slash command", "add a command", "write a custom command", "define command arguments", "use command frontmatter", "organize commands", "create command with file references", "interactive command", "use AskUserQuestion in command", or needs guidance on slash command structure, YAML frontmatter fields, dynamic arguments, bash execution in commands, user interaction patterns, or command development best practices for Claude Code.
version: 0.2.0

Command Development for Claude Code

Overview

Slash commands are frequently-used prompts defined as Markdown files that Claude executes during interactive sessions. Understanding command structure, frontmatter options, and dynamic features enables creating powerful, reusable workflows.

**Key concepts:**

• Markdown file format for commands
• YAML frontmatter for configuration
• Dynamic arguments and file references
• Bash execution for context
• Command organization and namespacing

Command Basics

What is a Slash Command?

A slash command is a Markdown file containing a prompt that Claude executes when invoked. Commands provide:

• **Reusability**: Define once, use repeatedly
• **Consistency**: Standardize common workflows
• **Sharing**: Distribute across team or projects
• **Efficiency**: Quick access to complex prompts

Critical: Commands are Instructions FOR Claude

**Commands are written for agent consumption, not human consumption.**

When a user invokes `/command-name`, the command content becomes Claude's instructions. Write commands as directives TO Claude about what to do, not as messages TO the user.

**Correct approach (instructions for Claude):**

Review this code for security vulnerabilities including:
- SQL injection
- XSS attacks
- Authentication issues

Provide specific line numbers and severity ratings.

**Incorrect approach (messages to user):**

This command will review your code for security issues.
You'll receive a report with vulnerability details.

The first example tells Claude what to do. The second tells the user what will happen but doesn't instruct Claude. Always use the first approach.

Command Locations

**Project commands** (shared with team):

• Location: `.claude/commands/`
• Scope: Available in specific project
• Label: Shown as "(project)" in `/help`
• Use for: Team workflows, project-specific tasks

**Personal commands** (available everywhere):

• Location: `~/.claude/commands/`
• Scope: Available in all projects
• Label: Shown as "(user)" in `/help`
• Use for: Personal workflows, cross-project utilities

**Plugin commands** (bundled with plugins):

• Location: `plugin-name/commands/`
• Scope: Available when plugin installed
• Label: Shown as "(plugin-name)" in `/help`
• Use for: Plugin-specific functionality

File Format

Basic Structure

Commands are Markdown files with `.md` extension:

.claude/commands/
├── review.md           # /review command
├── test.md             # /test command
└── deploy.md           # /deploy command

**Simple command:**

Review this code for security vulnerabilities including:
- SQL injection
- XSS attacks
- Authentication bypass
- Insecure data handling

No frontmatter needed for basic commands.

With YAML Frontmatter

Add configuration using YAML frontmatter:

---
description: Review code for security issues
allowed-tools: Read, Grep, Bash(git:*)
model: sonnet
---

Review this code for security vulnerabilities...

YAML Frontmatter Fields

description

**Purpose:** Brief description shown in `/help` **Type:** String **Default:** First line of command prompt

---
description: Review pull request for code quality
---

**Best practice:** Clear, actionable description (under 60 characters)

allowed-tools

**Purpose:** Specify which tools command can use **Type:** String or Array **Default:** Inherits from conversation

---
allowed-tools: Read, Write, Edit, Bash(git:*)
---

**Patterns:**

• `Read, Write, Edit` - Specific tools
• `Bash(git:*)` - Bash with git commands only
• `*` - All tools (rarely needed)

**Use when:** Command requires specific tool access

model

**Purpose:** Specify model for command execution **Type:** String (sonnet, opus, haiku) **Default:** Inherits from conversation

---
model: haiku
---

**Use cases:**

• `haiku` - Fast, simple commands
• `sonnet` - Standard workflows
• `opus` - Complex analysis

argument-hint

**Purpose:** Document expected arguments for autocomplete **Type:** String **Default:** None

---
argument-hint: [pr-number] [priority] [assignee]
---

**Benefits:**

• Helps users understand command arguments
• Improves command discovery
• Documents command interface

disable-model-invocation

**Purpose:** Prevent SlashCommand tool from programmatically calling command **Type:** Boolean **Default:** false

---
disable-model-invocation: true
---

**Use when:** Command should only be manually invoked

Dynamic Arguments

Using $ARGUMENTS

Capture all arguments as single string:

---
description: Fix issue by number
argument-hint: [issue-number]
---

Fix issue #$ARGUMENTS following our coding standards and best practices.

**Usage:**

> /fix-issue 123
> /fix-issue 456

**Expands to:**

Fix issue #123 following our coding standards...
Fix issue #456 following our coding standards...

Using Positional Arguments

Capture individual arguments with `$1`, `$2`, `$3`, etc.:

---
description: Review PR with priority and assignee
argument-hint: [pr-number] [priority] [assignee]
---

Review pull request #$1 with priority level $2.
After review, assign to $3 for follow-up.

**Usage:**

> /review-pr 123 high alice

**Expands to:**

Review pull request #123 with priority level high.
After review, assign to alice for follow-up.
`