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Shell tools let Claude Code run commands directly in your environment. On Unix-like systems, BashTool handles all shell execution. On Windows, PowerShellTool provides equivalent functionality using PowerShell.

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BashTool

Executes a shell command and returns its stdout, stderr, and exit code. Supports long-running commands, pipeline expressions, and any program available in your PATH.

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Parameters

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command
string
required
The bash command to execute.
​
timeout
number
Maximum time to wait for the command to complete, in milliseconds. Defaults to 120000 (2 minutes). The maximum allowed value is configurable per deployment.
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description
string
A brief human-readable description of what the command does (e.g. "Install npm dependencies"). Shown in the UI while the command runs.
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workdir
string
Absolute path to the directory in which to run the command. Defaults to the current working directory of the session.

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Returns

The combined stdout and stderr output of the command, truncated if it exceeds the result size limit.

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Example

Running tests in a specific directory: 
{
  "command": "npm test -- --reporter=verbose",
  "workdir": "/home/user/project",
  "timeout": 60000,
  "description": "Run test suite"
}
Installing dependencies and building: 
npm ci && npm run build
Each BashTool invocation runs in a fresh shell. Environment variables, cd changes, and shell functions do not persist between calls. To run a command in a specific directory, use the workdir parameter rather than cd && command.
On supported platforms, commands run inside a sandbox that restricts access to sensitive system resources. The sandbox is bypassed automatically when a command genuinely requires broader access, subject to your permission settings.

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PowerShellTool

Executes a PowerShell command on Windows. Available only on Windows platforms.

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Parameters

​
command
string
required
The PowerShell command or script to execute.
​
timeout
number
Maximum time to wait for the command to complete, in milliseconds. Defaults to 120000 (2 minutes).
​
description
string
A brief human-readable description of what the command does.
​
workdir
string
Absolute path to the directory in which to run the command. Defaults to the current working directory of the session.

​
Returns

The combined output of the PowerShell command.

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Example

Listing processes matching a name: 
{
  "command": "Get-Process | Where-Object { $_.Name -like 'node*' }",
  "description": "List Node.js processes"
}
PowerShellTool is only available when Claude Code is running on Windows. On macOS and Linux, use BashTool instead.

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