# Gemini CLI tools

The Gemini CLI includes built-in tools that the Gemini model uses to interact
with your local environment, access information, and perform actions. These
tools enhance the CLI's capabilities, enabling it to go beyond text generation
and assist with a wide range of tasks.

## Overview of Gemini CLI tools

In the context of the Gemini CLI, tools are specific functions or modules that
the Gemini model can request to be executed. For example, if you ask Gemini to
"Summarize the contents of `my_document.txt`," the model will likely identify
the need to read that file and will request the execution of the `read_file`
tool.

The core component (`packages/core`) manages these tools, presents their
definitions (schemas) to the Gemini model, executes them when requested, and
returns the results to the model for further processing into a user-facing
response.

These tools provide the following capabilities:

- **Access local information:** Tools allow Gemini to access your local file
  system, read file contents, list directories, etc.
- **Execute commands:** With tools like `run_shell_command`, Gemini can run
  shell commands (with appropriate safety measures and user confirmation).
- **Interact with the web:** Tools can fetch content from URLs.
- **Take actions:** Tools can modify files, write new files, or perform other
  actions on your system (again, typically with safeguards).
- **Ground responses:** By using tools to fetch real-time or specific local
  data, Gemini's responses can be more accurate, relevant, and grounded in your
  actual context.

## How to use Gemini CLI tools

To use Gemini CLI tools, provide a prompt to the Gemini CLI. The process works
as follows:

1.  You provide a prompt to the Gemini CLI.
2.  The CLI sends the prompt to the core.
3.  The core, along with your prompt and conversation history, sends a list of
    available tools and their descriptions/schemas to the Gemini API.
4.  The Gemini model analyzes your request. If it determines that a tool is
    needed, its response will include a request to execute a specific tool with
    certain parameters.
5.  The core receives this tool request, validates it, and (often after user
    confirmation for sensitive operations) executes the tool.
6.  The output from the tool is sent back to the Gemini model.
7.  The Gemini model uses the tool's output to formulate its final answer, which
    is then sent back through the core to the CLI and displayed to you.

You will typically see messages in the CLI indicating when a tool is being
called and whether it succeeded or failed.

## Security and confirmation

Many tools, especially those that can modify your file system or execute
commands (`write_file`, `edit`, `run_shell_command`), are designed with safety
in mind. The Gemini CLI will typically:

- **Require confirmation:** Prompt you before executing potentially sensitive
  operations, showing you what action is about to be taken.
- **Utilize sandboxing:** All tools are subject to restrictions enforced by
  sandboxing (see [Sandboxing in the Gemini CLI](../cli/sandbox.md)). This means
  that when operating in a sandbox, any tools (including MCP servers) you wish
  to use must be available _inside_ the sandbox environment. For example, to run
  an MCP server through `npx`, the `npx` executable must be installed within the
  sandbox's Docker image or be available in the `sandbox-exec` environment.

It's important to always review confirmation prompts carefully before allowing a
tool to proceed.

## Learn more about Gemini CLI's tools

Gemini CLI's built-in tools can be broadly categorized as follows:

- **[File System Tools](./file-system.md):** For interacting with files and
  directories (reading, writing, listing, searching, etc.).
- **[Shell Tool](./shell.md) (`run_shell_command`):** For executing shell
  commands.
- **[Web Fetch Tool](./web-fetch.md) (`web_fetch`):** For retrieving content
  from URLs.
- **[Web Search Tool](./web-search.md) (`google_web_search`):** For searching
  the web.
- **[Memory Tool](./memory.md) (`save_memory`):** For saving and recalling
  information across sessions.
- **[Todo Tool](./todos.md) (`write_todos`):** For managing subtasks of complex
  requests.

Additionally, these tools incorporate:

- **[MCP servers](./mcp-server.md)**: MCP servers act as a bridge between the
  Gemini model and your local environment or other services like APIs.
- **[Agent Skills](../cli/skills.md)**: On-demand expertise packages that are
  activated via the `activate_skill` tool to provide specialized guidance and
  resources.
- **[Sandboxing](../cli/sandbox.md)**: Sandboxing isolates the model and its
  changes from your environment to reduce potential risk.
