Tools reference

Complete reference for the tools Claude Code can use, including permission requirements.

Claude Code has access to a set of built-in tools that help it understand and modify your codebase. The tool names are the exact strings you use in permission rules, subagent tool lists, and hook matchers. To disable a tool entirely, add its name to the deny array in your permission settings.

To add custom tools, connect an MCP server. To extend Claude with reusable prompt-based workflows, write a skill, which runs through the existing Skill tool rather than adding a new tool entry.

Permission rules can be configured using /permissions or in permission settings. Also see Tool-specific permission rules.

Bash tool behavior

The Bash tool runs each command in a separate process with the following persistence behavior:

• When Claude runs cd in the main session, the new working directory carries over to later Bash commands as long as it stays inside the project directory or an additional working directory you added with --add-dir, /add-dir, or additionalDirectories in settings. Subagent sessions never carry over working directory changes.
  • If cd lands outside those directories, Claude Code resets to the project directory and appends Shell cwd was reset to <dir> to the tool result.
  • To disable this carry-over so every Bash command starts in the project directory, set CLAUDE_BASH_MAINTAIN_PROJECT_WORKING_DIR=1.
• Environment variables do not persist. An export in one command will not be available in the next.

Activate your virtualenv or conda environment before launching Claude Code. To make environment variables persist across Bash commands, set CLAUDE_ENV_FILE to a shell script before launching Claude Code, or use a SessionStart hook to populate it dynamically.

LSP tool behavior

The LSP tool gives Claude code intelligence from a running language server. After each file edit, it automatically reports type errors and warnings so Claude can fix issues without a separate build step. Claude can also call it directly to navigate code:

• Jump to a symbol's definition
• Find all references to a symbol
• Get type information at a position
• List symbols in a file or workspace
• Find implementations of an interface
• Trace call hierarchies

The tool is inactive until you install a code intelligence plugin for your language. The plugin bundles the language server configuration, and you install the server binary separately.

Monitor tool

The Monitor tool lets Claude watch something in the background and react when it changes, without pausing the conversation. Ask Claude to:

• Tail a log file and flag errors as they appear
• Poll a PR or CI job and report when its status changes
• Watch a directory for file changes
• Track output from any long-running script you point it at

Claude writes a small script for the watch, runs it in the background, and receives each output line as it arrives. You keep working in the same session and Claude interjects when an event lands. Stop a monitor by asking Claude to cancel it or by ending the session.

Monitor uses the same permission rules as Bash, so allow and deny patterns you have set for Bash apply here too. It is not available on Amazon Bedrock, Google Vertex AI, or Microsoft Foundry. It is also not available when DISABLE_TELEMETRY or CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC is set.

Plugins can declare monitors that start automatically when the plugin is active, instead of asking Claude to start them. See plugin monitors.

PowerShell tool

The PowerShell tool lets Claude run PowerShell commands natively. On Windows, this means commands run in PowerShell instead of routing through Git Bash. On Windows without Git Bash, the tool is enabled automatically. On Windows with Git Bash installed, the tool is rolling out progressively. On Linux, macOS, and WSL, the tool is opt-in.

Enable the PowerShell tool

Set CLAUDE_CODE_USE_POWERSHELL_TOOL=1 in your environment or in settings.json:

{
  "env": {
    "CLAUDE_CODE_USE_POWERSHELL_TOOL": "1"
  }
}

On Windows, set the variable to 0 to opt out of the rollout. On Linux, macOS, and WSL, the tool requires PowerShell 7 or later: install pwsh and ensure it is on your PATH.

On Windows, Claude Code auto-detects pwsh.exe for PowerShell 7+ with a fallback to powershell.exe for PowerShell 5.1. When the tool is enabled, Claude treats PowerShell as the primary shell. The Bash tool remains available for POSIX scripts when Git Bash is installed.

Shell selection in settings, hooks, and skills

Three additional settings control where PowerShell is used:

• "defaultShell": "powershell" in settings.json: routes interactive ! commands through PowerShell. Requires the PowerShell tool to be enabled.
• "shell": "powershell" on individual command hooks: runs that hook in PowerShell. Hooks spawn PowerShell directly, so this works regardless of CLAUDE_CODE_USE_POWERSHELL_TOOL.
• shell: powershell in skill frontmatter: runs !`command` blocks in PowerShell. Requires the PowerShell tool to be enabled.

The same main-session working-directory reset behavior described under the Bash tool section applies to PowerShell commands, including the CLAUDE_BASH_MAINTAIN_PROJECT_WORKING_DIR environment variable.

Preview limitations

The PowerShell tool has the following known limitations during the preview:

• PowerShell profiles are not loaded
• On Windows, sandboxing is not supported

Check which tools are available

Your exact tool set depends on your provider, platform, and settings. To check what's loaded in a running session, ask Claude directly:

What tools do you have access to?

Claude gives a conversational summary. For exact MCP tool names, run /mcp.

See also

• MCP servers: add custom tools by connecting external servers
• Permissions: permission system, rule syntax, and tool-specific patterns
• Subagents: configure tool access for subagents
• Hooks: run custom commands before or after tool execution