# Agent Skills

Agent Skills allow you to extend Gemini CLI with specialized expertise,
procedural workflows, and task-specific resources. Based on the
[Agent Skills](https://agentskills.io) open standard, a "skill" is a
self-contained directory that packages instructions and assets into a
discoverable capability.

## Overview

Unlike general context files ([`GEMINI.md`](./gemini-md.md)), which provide
persistent workspace-wide background, Skills represent **on-demand expertise**.
This allows Gemini to maintain a vast library of specialized capabilities—such
as security auditing, cloud deployments, or codebase migrations—without
cluttering the model's immediate context window.

Gemini autonomously decides when to employ a skill based on your request and the
skill's description. When a relevant skill is identified, the model "pulls in"
the full instructions and resources required to complete the task using the
`activate_skill` tool.

## Key Benefits

- **Shared Expertise:** Package complex workflows (like a specific team's PR
  review process) into a folder that anyone can use.
- **Repeatable Workflows:** Ensure complex multi-step tasks are performed
  consistently by providing a procedural framework.
- **Resource Bundling:** Include scripts, templates, or example data alongside
  instructions so the agent has everything it needs.
- **Progressive Disclosure:** Only skill metadata (name and description) is
  loaded initially. Detailed instructions and resources are only disclosed when
  the model explicitly activates the skill, saving context tokens.

## Skill Discovery Tiers

Gemini CLI discovers skills from three primary locations:

1.  **Workspace Skills** (`.gemini/skills/`): Workspace-specific skills that are
    typically committed to version control and shared with the team.
2.  **User Skills** (`~/.gemini/skills/`): Personal skills available across all
    your workspaces.
3.  **Extension Skills**: Skills bundled within installed
    [extensions](../extensions/index.md).

**Precedence:** If multiple skills share the same name, higher-precedence
locations override lower ones: **Workspace > User > Extension**.

## Managing Skills

### In an Interactive Session

Use the `/skills` slash command to view and manage available expertise:

- `/skills list` (default): Shows all discovered skills and their status.
- `/skills disable <name>`: Prevents a specific skill from being used.
- `/skills enable <name>`: Re-enables a disabled skill.
- `/skills reload`: Refreshes the list of discovered skills from all tiers.

_Note: `/skills disable` and `/skills enable` default to the `user` scope. Use
`--scope workspace` to manage workspace-specific settings._

### From the Terminal

The `gemini skills` command provides management utilities:

```bash
# List all discovered skills
gemini skills list

# Install a skill from a Git repository, local directory, or zipped skill file (.skill)
# Uses the user scope by default (~/.gemini/skills)
gemini skills install https://github.com/user/repo.git
gemini skills install /path/to/local/skill
gemini skills install /path/to/local/my-expertise.skill

# Install a specific skill from a monorepo or subdirectory using --path
gemini skills install https://github.com/my-org/my-skills.git --path skills/frontend-design

# Install to the workspace scope (.gemini/skills)
gemini skills install /path/to/skill --scope workspace

# Uninstall a skill by name
gemini skills uninstall my-expertise --scope workspace

# Enable a skill (globally)
gemini skills enable my-expertise

# Disable a skill. Can use --scope to specify workspace or user (defaults to workspace)
gemini skills disable my-expertise --scope workspace
```

## Creating a Skill

A skill is a directory containing a `SKILL.md` file at its root. This file uses
YAML frontmatter for metadata and Markdown for instructions.

### Folder Structure

Skills are self-contained directories. At a minimum, a skill requires a
`SKILL.md` file, but can include other resources:

```text
my-skill/
├── SKILL.md       (Required) Instructions and metadata
├── scripts/       (Optional) Executable scripts/tools
├── references/    (Optional) Static documentation and examples
└── assets/        (Optional) Templates and binary resources
```

### Basic Structure (SKILL.md)

```markdown
---
name: <unique-name>
description: <what the skill does and when Gemini should use it>
---

<your instructions for how the agent should behave / use the skill>
```

- **`name`**: A unique identifier (lowercase, alphanumeric, and dashes).
- **`description`**: The most critical field. Gemini uses this to decide when
  the skill is relevant. Be specific about the expertise provided.
- **Body**: Everything below the second `---` is injected as expert procedural
  guidance for the model.

### Example: Team Code Reviewer

Create `~/.gemini/skills/code-reviewer/SKILL.md`:

```markdown
---
name: code-reviewer
description:
  Expertise in reviewing code for style, security, and performance. Use when the
  user asks for "feedback," a "review," or to "check" their changes.
---

# Code Reviewer

You are an expert code reviewer. When reviewing code, follow this workflow:

1.  **Analyze**: Review the staged changes or specific files provided. Ensure
    that the changes are scoped properly and represent minimal changes required
    to address the issue.
2.  **Style**: Ensure code follows the workspace's conventions and idiomatic
    patterns as described in the `GEMINI.md` file.
3.  **Security**: Flag any potential security vulnerabilities.
4.  **Tests**: Verify that new logic has corresponding test coverage and that
    the test coverage adequately validates the changes.

Provide your feedback as a concise bulleted list of "Strengths" and
"Opportunities."
```

### Resource Conventions

While you can structure your skill directory however you like, the Agent Skills
standard encourages these conventions:

- **`scripts/`**: Executable scripts (bash, python, node) the agent can run.
- **`references/`**: Static documentation, schemas, or example data for the
  agent to consult.
- **`assets/`**: Code templates, boilerplate, or binary resources.

When a skill is activated, Gemini CLI provides the model with a tree view of the
entire skill directory, allowing it to discover and utilize these assets.

## How it Works (Security & Privacy)

1.  **Discovery**: At the start of a session, Gemini CLI scans the discovery
    tiers and injects the name and description of all enabled skills into the
    system prompt.
2.  **Activation**: When Gemini identifies a task matching a skill's
    description, it calls the `activate_skill` tool.
3.  **Consent**: You will see a confirmation prompt in the UI detailing the
    skill's name, purpose, and the directory path it will gain access to.
4.  **Injection**: Upon your approval:
    - The `SKILL.md` body and folder structure is added to the conversation
      history.
    - The skill's directory is added to the agent's allowed file paths, granting
      it permission to read any bundled assets.
5.  **Execution**: The model proceeds with the specialized expertise active. It
    is instructed to prioritize the skill's procedural guidance within reason.
