Antigravity Customization System Guide

The Antigravity Customization System allows you to tailor the agent's behavior, teach it new workflows, enforce guidelines, and integrate it with external tools. By customizing the agent, you can transition it from a general-purpose assistant to an expert pair programmer specialized in your project's codebase and processes.

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Customization Types: Quick Reference

Choose the right customization type based on your goal:

Type	Config File/Folder	Scope	Best For	Learn More
Rules	GEMINI.md, AGENTS.md	Contextual / Hierarchical	Enforcing coding styles, API restrictions, and local guidelines.	Rules Guide
Skills	skills/<name>/SKILL.md	On-Demand (Progressive)	Teaching the agent multi-step procedures, runbooks, and tool workflows.	Skills Guide
Plugins	plugins/<name>/plugin.json	Bundle	Packaging related skills, rules, and MCP configs into a single unit.	Plugins Guide
Hooks	hooks.json	Lifecycle Event	Running scripts/commands at specific agent lifecycle points (e.g., pre-tool execution).	Hooks Guide
MCP Servers	mcp_config.json	Tool Integration	Connecting the agent to external services and custom tool providers.	MCP Guide

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Customization Discovery and Locations

Antigravity automatically discovers your own customizations by traversing specific directories. Built-in customizations are not found this way: the agent config names the ones it mounts.

Discovery Locations

1. Workspace Customizations (Project-Specific):
   • Path: .agents/ (or .agent/, _agents/, _agent/) at the root of
     your project.
   • Use this to share customizations with your team by checking them into
     version control (VCS).
   • The agent walks from your current working directory up to the repository
     root (e.g., the folder containing .git) to find these directories.
2. Directory & Project Rules (Hierarchical):
   • Paths: GEMINI.md, AGENTS.md, .agents/rules/*.md
   • As you open or edit files, the agent walks up from the file's directory
     to the repository root, loading all rules it finds.
3. Global Configuration (Machine-Local):
   • Path: ~/.gemini/config/
   • Applies to all projects and workspaces run on your machine.

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Loading Priority and Precedence

When multiple customizations are discovered, they are loaded and applied in a specific order. If there are naming conflicts (e.g., two skills with the same name), the higher-priority customization overrides the lower-priority one.

The priority order (from highest to lowest) is:

1. Workspace Project: Hierarchical discovery walking up from the CWD to the repository root.
2. Declared Configurations: Customizations explicitly listed in skills.json or plugins.json in your workspace.
3. Global Discovery: ~/.gemini/config/
4. Built-in Customizations: Default skills bundled with the application, mounted by name rather than discovered.
5. Global Declared Configurations: Explicitly listed in global JSON configs.

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How Customizations are Applied

Progressive Disclosure (Skills and Rules)

To prevent overwhelming the model's context window, Antigravity uses

progressive disclosure:

• Skills are not loaded into the context window by default. Only their names and descriptions are injected. The full content of a skill is only loaded if the model (or the user) explicitly decides to activate it.
• Rules with trigger: model_decision behave similarly. Only always_on rules are loaded unconditionally.

Deduplication

All customizations (especially rules) are deduplicated by their resolved file paths. A rule file will never be injected more than once in a single conversation turn, even if it matches multiple trigger conditions.

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Advanced Management: JSON Configs

For customizations stored in non-standard locations, you can use skills.json and plugins.json to explicitly register them and inherit from shared configurations.

• Learn how to configure these in the JSON Configurations Guide.