How to Install Google Agent Skills Plugins: CLI Commands for Claude Code, Codex, and Antigravity

Google Agent Skills plugins are installed via harness-specific CLI commands after adding the google/skills repository with npx skills add google/skills.

The google/skills repository hosts open-source agent capabilities packaged as plugins for large language model (LLM) agent harnesses. Understanding the correct installation commands for Google Agent Skills plugins ensures seamless integration with your preferred development environment, whether you use Claude Code, Codex, or Antigravity CLI.

Prerequisites

Before installing individual plugins, you must register the entire skills catalog with your environment. According to the source code in README.md, run the following global command:

npx skills add google/skills

This command pulls the full catalog of available skills into your workflow, enabling subsequent plugin-specific installations.

Installation Commands by Agent Harness

Each LLM agent harness implements its own plugin management interface. The installation commands for Google Agent Skills plugins vary depending on your target platform as documented in the repository's installation table (lines 81-85 of README.md).

Claude Code

For Anthropic's Claude Code agent, you must first add the Google Skills marketplace, then install specific plugins using the @google-plugins namespace.

Execute these commands in your terminal:

# Add the Google Skills marketplace

claude plugin marketplace add google/skills

# Install a specific plugin (replace <plugin> with the skill name)

claude plugin install <plugin>@google-plugins

For example, to install the google-cloud-recipe-onboarding plugin:

claude plugin install google-cloud-recipe-onboarding@google-plugins

Codex

OpenAI's Codex agent requires marketplace registration followed by UI-based selection. First, run the CLI command to add the marketplace:

codex plugin marketplace add google/skills

Then open the /plugins browser interface within Codex and select the desired plugin from the Google Skills catalog to complete installation.

Antigravity CLI

The Antigravity CLI (agy) supports direct URL-based installation without marketplace registration. Install plugins by specifying the full GitHub path to the skill directory:

agy plugin install https://github.com/google/skills/<plugin-path>

For instance, to install the google-cloud-recipe-onboarding skill located at skills/cloud/google-cloud-recipe-onboarding:

agy plugin install https://github.com/google/skills/skills/cloud/google-cloud-recipe-onboarding

Source Files and Skill Definitions

The installation instructions are maintained in README.md at the repository root, specifically around lines 81-85 where the harness-specific tables reside. Individual skill definitions, including configuration and documentation, are stored in dedicated directories such as skills/cloud/google-cloud-recipe-onboarding/SKILL.md.

Summary

• Initialize the catalog with npx skills add google/skills before installing individual plugins
• Claude Code uses marketplace registration followed by claude plugin install <name>@google-plugins
• Codex requires codex plugin marketplace add google/skills then UI selection via /plugins
• Antigravity CLI installs directly from GitHub URLs using agy plugin install with the full repository path
• All installation methods reference the google/skills repository as the source of truth

Frequently Asked Questions

What is the prerequisite command for all Google Agent Skills installations?

You must first run npx skills add google/skills to register the repository with your environment. This command applies universally across Claude Code, Codex, and Antigravity CLI workflows before harness-specific plugin installation.

How do I install a specific plugin in Claude Code?

First add the marketplace with claude plugin marketplace add google/skills, then install using the plugin name suffixed with @google-plugins. For example: claude plugin install google-cloud-recipe-onboarding@google-plugins.

Can I install Google Agent Skills plugins without using marketplace commands?

Yes, if you use Antigravity CLI. Instead of marketplace registration, execute agy plugin install followed by the complete GitHub URL to the skill directory, such as https://github.com/google/skills/skills/cloud/google-cloud-recipe-onboarding.

Where are the skill definitions stored in the repository?

Each skill's core documentation and configuration reside in individual directories under the skills/ path. For example, the google-cloud-recipe-onboarding skill definition is located at skills/cloud/google-cloud-recipe-onboarding/SKILL.md within the google/skills repository.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}