> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/killlowkey/claude-code/llms.txt
> Use this file to discover all available pages before exploring further.

# Shell Tools

> Tools for executing shell commands and interacting with the system.

Shell tools let Claude run commands on your machine. Every command is shown to you before execution and requires your approval (unless you've enabled auto-approval).

## BashTool

Executes a shell command in your environment. This is the most powerful tool — it can run test suites, build scripts, package managers, git commands, and anything else your shell supports.

**Usage pattern:**

```
> Run the test suite
> Install the missing dependency
> Build the project and show me any errors
> Run `npm run lint` and fix the issues it finds
```

**What Claude uses it for:**

* Running tests: `npm test`, `pytest`, `cargo test`
* Building: `npm run build`, `make`, `gradle build`
* Package management: `npm install`, `pip install`, `cargo add`
* Git operations: `git status`, `git log`, `git stash`
* File system operations: `mkdir`, `cp`, `mv`
* Any other shell command

<Warning>
  BashTool can execute any shell command. Claude will always show you the command before running it. Review carefully — especially commands that delete files or make network requests.
</Warning>

**Permission behavior:**

* First use: Claude shows the command and asks for approval
* You can approve once, approve always for a pattern, or deny
* In plan mode, BashTool commands are planned but not executed until you confirm

## PowerShellTool

On Windows, PowerShellTool runs commands in a PowerShell session instead of bash.

**Usage pattern:**

```
> List files in the current directory
> Run the build script
```

**Behavior:** Same permission model as BashTool. Claude selects the appropriate shell tool based on the detected platform.

## REPLTool

Runs code in an interactive REPL session that persists across calls within a conversation. Useful for iterative evaluation and exploration.

**Usage pattern:**

```
> Evaluate this TypeScript snippet
> Test this regular expression against sample data
```

<Tip>
  For quick one-off evaluations, Claude often uses BashTool with `node -e` or similar. REPLTool is used when state needs to persist across multiple evaluations.
</Tip>