Gemini Custom Slash Commands Skill

Overview

Gemini Custom Slash Commands allow you to extend the Gemini CLI with your own reusable workflows. These commands are defined in .toml files and can execute complex prompts, run shell commands, and read file contents.

Key Features

• Prompt Reuse: Save frequently used prompts as commands.
• Context Injection: Use {{args}} to pass user input into specific parts of the prompt.
• Shell Execution: Run shell commands with !{cmd} and inject their output.
• File Content: Read and inject file contents with @{path}.
• User or Project Scope: Define commands globally or per-project.

File Structure

Commands are defined in TOML files located in:

• Project Scope: .gemini/commands/ (Takes precedence, version controlled).
• User Scope: ~/.gemini/commands/ (Global availability).

Naming Convention

• The filename determines the command name: status.toml -> /status
• Subdirectories create namespaced commands: git/commit.toml -> /git:commit

Command Format (TOML)

A command file consists of metadata and the prompt definition.

description = "Brief description of what the command does"

# The prompt sent to the model.
# Use triple quotes """ for multi-line strings.
prompt = """
Instructions for the agent.
...
"""

Argument Handling ({{args}})

• Explicit Injection: Use {{args}} to place the user's input exactly where needed.

  prompt = "Explain this concept: {{args}}"
  

• Default Behavior: If {{args}} is NOT present, the user's input is appended to the end of the prompt.

Shell Command Injection (!{cmd})

Execute shell commands and insert their output into the prompt. Security Note: {{args}} inside !{...} is automatically shell-escaped.

prompt = """
Summarize the following git diff:
!{git diff {{args}}}
"""

File Content Injection (@{path})

Read file or directory contents and insert them into the prompt.

prompt = """
Review this code file:
@{src/main.rs}
"""

Examples

1. Simple Explanation

# ~/.gemini/commands/explain.toml
description = "Explain a concept simply"
prompt = """
Explain the following concept to a 5-year old:
{{args}}
"""

Usage: /explain quantum physics

2. Code Review with Context

# .gemini/commands/review.toml
description = "Review staged changes"
prompt = """
Please review the staged changes in this git repository.
Focus on security and performance.

Changes:
!{git diff --staged}
"""

Usage: /review

3. Log Analysis

# .gemini/commands/analyze-logs.toml
description = "Analyze logs for errors"
prompt = """
Analyze these logs for critical errors:
!{tail -n 50 /var/log/syslog}
"""

Usage: /analyze-logs

Best Practices

1. Descriptive Names: Choose clear filenames (e.g., daily-brief.toml).
2. Clear Descriptions: The description field helps you identify the command in /help.
3. Use {{args}}: For precise control over where user input goes.
4. Leverage Shell Commands: Use !{...} to fetch dynamic data (git status, logs, etc.).

This skill provides everything you need to create your own custom Gemini CLI slash commands!