Creating Commands

Creating Slash Commands

This Skill provides comprehensive knowledge about creating effective slash commands in Claude Code.

What Are Slash Commands?

Slash commands are user-invoked operations that start with /. When executed, they expand to a full prompt that Claude processes. They're different from subagents (which are automatically invoked) - slash commands require explicit user action.

Critical Insight - Thin Wrappers: The best practice for slash commands is to treat them as thin wrappers or triggers that activate Skills. The command file itself should NOT contain complex workflow logic - that belongs in a SKILL.md file. Commands are simply user-friendly aliases that point to specific skills or workflows.

Command → Skill → (Subagent): This is the ideal flow:

1. User invokes /command
2. Command activates a specific Skill
3. Skill (the "playbook") guides the agent through the process
4. Agent may delegate to subagents as needed

Plugin System Integration (October 2025)

As of October 2025, plugins are the standard way to bundle and share slash commands.

What Are Plugins?

Plugins bundle multiple components together:

• Slash commands
• Subagents
• MCP servers
• Hooks
• Skills

Installing Command Plugins

/plugin marketplace add <url>    # Add plugin source
/plugin install <name>           # Install plugin
/plugin list                     # Show installed plugins
/plugin uninstall <name>         # Remove plugin

Creating Commands in Plugins

Commands in plugins work identically to standalone commands:

• Same YAML frontmatter
• Same argument patterns
• Same bash execution

Benefit: Version control, selective activation, easier distribution across teams.

See: Official plugin documentation for creating distributable command collections.

File Structure

Project commands: .claude/commands/{command-name}.md Personal commands: ~/.claude/commands/{command-name}.md

Format:

---
description: Brief description of what this command does
argument-hint: [arg1] [arg2]  # Optional
allowed-tools: Bash(git:*), Read, Write  # Optional
model: haiku  # Optional
disable-model-invocation: false  # Optional
---

Command prompt that Claude will execute.
Can use $ARGUMENTS or $1, $2, $3, etc.

YAML Frontmatter Fields

Optional Fields (All Are Optional)

description (string)

• Brief description shown in /help
• If omitted, uses first line of prompt
• Keep concise (one sentence)

argument-hint (string)

• Shows expected arguments in autocomplete
• Examples: [filename], [message], add [tag] | remove [tag]
• Helps users know what to provide

allowed-tools (comma-separated string)

• Tools this command can use
• If omitted, inherits from conversation
• Use for command-specific restrictions

model (string)

• Specific model: sonnet, opus, haiku
• If omitted, inherits from conversation
• Use haiku for simple/fast commands

disable-model-invocation (boolean)

• If true, prevents SlashCommand tool from calling this command
• Default: false
• Use to keep commands user-only

Command Arguments

Using $ARGUMENTS (All Arguments)

Captures everything after the command name:

---
description: Fix issue following coding standards
---

Fix issue #$ARGUMENTS following our coding standards

Usage:

/fix-issue 123 high-priority
# $ARGUMENTS becomes "123 high-priority"

Using $1, $2, $3 (Positional Arguments)

Access specific arguments individually:

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

Review PR #$1 with priority $2 and assign to $3.
Focus on security, performance, and code style.

Usage:

/review-pr 456 high alice
# $1="456", $2="high", $3="alice"

@-Mention Support (August 2025)

Commands support @-mentions in arguments with typeahead support:

File References:

/review-pr @src/components/Header.tsx
/analyze @tests/test_auth.py

Agent References:

/delegate @agent:security-expert
/consult @agent:code-reviewer

Benefits:

• Typeahead completion for file paths
• Clear intent (@ signals reference)
• Works with glob patterns: @src/utils/*.js

In Command Prompt:

---
description: Review specific files
argument-hint: [@file-path]
---

Review the implementation in $1

Focus on code quality, security, and maintainability.

Usage: /review-files @src/auth.ts @tests/test_auth.ts

When to Use Which

Use $ARGUMENTS:

• Flexible, variable-length input
• Natural language descriptions
• Unknown number of args

Use $1, $2, $3:

• Fixed structure
• Specific fields needed
• Build complex prompts with arg positioning

Bash Command Execution

Execute bash commands before the prompt runs using ! prefix.

Basic Execution

---
allowed-tools: Bash(git:*)
---

## Current Status

Git status: !`git status`

## Your Task

Based on the above status, create a commit.

The ! commands run first, output is included in prompt context.

Multiple Commands

---
allowed-tools: Bash(git:*), Bash(docker:*)
---

## Context

- Git status: !`git status`
- Docker status: !`docker ps`
- Current branch: !`git branch --show-current`

## Task

Deploy the current branch.

Required: allowed-tools

Must include Bash tool permissions:

---
allowed-tools: Bash(git status:*), Bash(git diff:*)
---

Current changes: !`git diff HEAD`

Specify exact commands or use wildcards:

• Bash(git:*) - All git commands
• Bash(git status:*), Bash(git diff:*) - Specific commands only

File References

Include file contents using @ prefix:

---
description: Review implementation
---

Review the implementation in @src/utils/helpers.js

Compare @src/old-version.js with @src/new-version.js

When command runs, files are automatically included in context.

Extended Thinking

Trigger extended thinking by including keywords:

---
description: Solve complex algorithm problem
---

Think carefully about this algorithm optimization problem: $ARGUMENTS

Consider multiple approaches before implementing.

Keywords that trigger thinking: "think carefully", "consider", "analyze deeply"

Commands and Skills Integration

Best Practice: Commands should activate Skills, not replace them.

The Thin Wrapper Pattern

Good - Command activates a Skill:

---
description: Run comprehensive code review
---

Activate the code-review-process Skill and review the current changes.

The actual review process (checklist, steps, output format) lives in .claude/skills/code-review-process/SKILL.md, not in the command file.

Bad - Command contains the entire process:

---
description: Run comprehensive code review
---

Review the code changes following these steps:
1. Check code style
2. Verify error handling
3. Look for security issues
[... 50 more lines of detailed process ...]

This defeats modularity and makes the process hard to maintain.

Why This Matters

• Reusability: Skills can be invoked by multiple commands or automatically by Claude
• Maintainability: Update the process once in SKILL.md, not in every command
• Clarity: Commands = user interface, Skills = implementation
• Modularity: Skills can reference other skills, creating composable workflows

Programmatic Command Invocation (SlashCommand Tool)

Claude can automatically invoke your commands during conversations using the SlashCommand tool.

How It Works

When you create a command with a populated description field, Claude can:

1. See the command in its tool list
2. Invoke it programmatically when relevant
3. Get the expanded prompt as input

Example:

---
description: Run all tests and report failures
---

Run the complete test suite and analyze failures.

Claude might invoke this automatically when user says: "Make sure everything still works"

Requirements

Must Have:

• description field populated (commands without descriptions are invisible)
• Under 15,000 character budget (see below)

Optional:

• disable-model-invocation: true - Prevents automatic invocation (user-only command)

Character Budget Limit

Claude can only see commands that fit within SLASH_COMMAND_TOOL_CHAR_BUDGET (default: 15,000 characters).

Managing Budget:

• Keep command prompts concise
• Use disable-model-invocation: true for internal/debug commands
• Increase limit in settings.json if needed:

{
  "SLASH_COMMAND_TOOL_CHAR_BUDGET": 30000
}

Best Practices

Enable Automatic Invocation:

• Clear, specific descriptions
• Common user phrases as triggers
• Thin wrappers to skills

Disable Automatic Invocation:

• Internal/debug commands
• Dangerous operations (deploy, delete)
• Commands needing explicit human approval

Encouraging Usage: Reference commands in CLAUDE.md:

To commit changes: Execute /commit command
For code review: Use /review command

This helps Claude map natural language → commands.

Command Patterns

Seven main patterns have emerged for effective slash commands:

1. Simple Action - Single operation (run tests, build project)
2. Context Gathering - Collect and present information (status, review prep)
3. Workflow - Multi-step sequences (branch creation, PR automation)
4. Validation - Pre-flight checks (pre-commit, pre-deploy)
5. Generation - Create code/files (scaffolding, boilerplate)
6. Skill Activation - Thin wrapper to skill (complex workflows)
7. Context Pollution Prevention - Delegate massive outputs to subagents

See patterns.md for detailed explanations, examples, and when to use each pattern.

Tool Restrictions and Model Selection

Tool Restriction Patterns:

# Read-only
allowed-tools: Read, Grep, Glob

# Git only
allowed-tools: Bash(git:*)

# Multiple specific tools
allowed-tools: Bash(git:*), Bash(npm:*), Bash(pytest:*)

Model Selection:

• model: haiku - Fast, cheap (simple commands)
• Omit model field - Uses conversation model (default)
• model: opus - Complex reasoning

See reference.md for detailed bash execution patterns, security considerations, and troubleshooting.

Examples

Quick Example - Thin Wrapper to Skill:

---
description: Run comprehensive code review
---

Activate the code-review-process Skill and review the current changes.

This demonstrates the thin wrapper pattern - the command is minimal, and the actual review process lives in a skill.

See examples.md for 7 detailed, real-world command examples covering all major patterns.

Command Organization

Flat (< 10 commands): All in .claude/commands/ Subdirectories (organized): Use git/, testing/ folders for grouping

Note: Subdirectories don't affect command names - /create-branch works regardless of location.

Best Practices

1. Thin Wrappers - Complex logic in skills, not commands
2. Clear Descriptions - "Run all tests and report failures" not "Tests"
3. Argument Hints - [pr-number] [priority] not [args]
4. Specific Tools - Bash(git:*) not Bash(*)
5. Context First - Gather info with ! before instructions
6. Heredocs - Use for commit messages to prevent injection

Testing and Troubleshooting

Testing Methods:

1. Manual invocation: /your-command arg1 arg2
2. Verify argument substitution: Check $1, $2 work
3. Test bash execution: Verify ! commands run

Common Issues:

• Command not found → Check filename, restart Claude Code
• Arguments not substituting → Use $1 in content, not frontmatter
• Bash not running → Add allowed-tools: Bash(...)
• Permission denied → Check tool permissions

See reference.md for complete troubleshooting guide with diagnose and fix steps.

Validation Checklist

Before finalizing a command:

• Description is clear and concise
• Argument hints provided (if using args)
• Tool permissions specified (if using tools)
• Arguments use proper format ($ARGUMENTS or $1, $2, etc.)
• Bash commands have ! and backticks
• Bash permissions match commands used
• Heredocs used for multi-line strings
• File tested with sample arguments

Summary

Essential Elements:

1. Clear description (what it does)
2. Argument hints (what to provide)
3. Proper argument substitution ($ARGUMENTS or $1-$9)
4. Tool permissions (if using tools)
5. Context gathering (using ! for bash)

Success Criteria:

• Command shows in /help
• Arguments substitute correctly
• Bash commands execute
• Claude produces expected result
• Tool permissions work