<!--
name: 'Tool Description: Bash'
description: Default SDK built-in tool description and input schema for Bash.
sdkPackage: '@anthropic-ai/claude-agent-sdk@0.3.168'
claudeCodeVersion: '2.1.168'
tool: "Bash"
-->
# Tool Description: Bash

## Metadata

- Request location: `tools[]`
- Tool name: `Bash`
- Input schema properties: `command`, `timeout`, `description`, `run_in_background`, `dangerouslyDisableSandbox`

## Description

Executes a bash command and returns its output.

- Working directory persists between calls, but prefer absolute paths — `cd` in a compound command can trigger a permission prompt. Shell state (env vars, functions) does not persist; the shell is initialized from the user's profile.
- IMPORTANT: Avoid using this tool to run `cat`, `head`, `tail`, `sed`, `awk`, or `echo` commands, unless explicitly instructed or after you have verified that a dedicated tool cannot accomplish your task. Instead, use the appropriate dedicated tool as this will provide a much better experience for the user.
- `timeout` is in milliseconds: default 120000, max 600000.
- `run_in_background` runs the command detached: it keeps running across turns and re-invokes you when it exits. No `&` needed. Foreground `sleep` is blocked; use Monitor with an until-loop to wait on a condition.

# Git
- Interactive flags (`-i`, e.g. `git rebase -i`, `git add -i`) are not supported in this environment.
- Use the `gh` CLI for GitHub operations (PRs, issues, API).
- Commit or push only when the user asks. If on the default branch, branch first.
- End git commit messages with:
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- End PR bodies with:
🤖 Generated with [Claude Code](https://claude.com/claude-code)

## Input Schema

```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "command": {
      "description": "The command to execute",
      "type": "string"
    },
    "timeout": {
      "description": "Optional timeout in milliseconds (max 600000)",
      "type": "number"
    },
    "description": {
      "description": "Clear, concise description of what this command does in active voice. Never use words like \"complex\" or \"risk\" in the description - just describe what it does.\n\nFor simple commands (git, npm, standard CLI tools), keep it brief (5-10 words):\n- ls → \"List files in current directory\"\n- git status → \"Show working tree status\"\n- npm install → \"Install package dependencies\"\n\nFor commands that are harder to parse at a glance (piped commands, obscure flags, etc.), add enough context to clarify what it does:\n- find . -name \"*.tmp\" -exec rm {} \\; → \"Find and delete all .tmp files recursively\"\n- git reset --hard origin/main → \"Discard all local changes and match remote main\"\n- curl -s url | jq '.data[]' → \"Fetch JSON from URL and extract data array elements\"",
      "type": "string"
    },
    "run_in_background": {
      "description": "Set to true to run this command in the background.",
      "type": "boolean"
    },
    "dangerouslyDisableSandbox": {
      "description": "Set this to true to dangerously override sandbox mode and run commands without sandboxing.",
      "type": "boolean"
    }
  },
  "required": [
    "command"
  ],
  "additionalProperties": false
}
```

## Token Impact

<!-- TOKEN_COUNT_START -->
- Complete definition estimated tokens: **1,034**
- Measurement: captured tool object serialized independently as JSON text against the common baseline
- Additivity: independent, non-additive estimate
<!-- TOKEN_COUNT_END -->