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.

Tool	Description	Permission Required
`Agent`	Spawns a subagent with its own context window to handle a task	No
`AskUserQuestion`	Asks multiple-choice questions to gather requirements or clarify ambiguity	No
`Bash`	Executes shell commands in your environment. See Bash tool behavior	Yes
`CronCreate`	Schedules a recurring or one-shot prompt within the current session. Tasks are session-scoped and restored on `--resume` or `--continue` if unexpired. See scheduled tasks	No
`CronDelete`	Cancels a scheduled task by ID	No
`CronList`	Lists all scheduled tasks in the session	No
`Edit`	Makes targeted edits to specific files	Yes
`EnterPlanMode`	Switches to plan mode to design an approach before coding	No
`EnterWorktree`	Creates an isolated git worktree and switches into it. Pass a `path` to switch into an existing worktree of the current repository instead of creating a new one. Not available to subagents	No
`ExitPlanMode`	Presents a plan for approval and exits plan mode	Yes
`ExitWorktree`	Exits a worktree session and returns to the original directory. Not available to subagents	No
`Glob`	Finds files based on pattern matching	No
`Grep`	Searches for patterns in file contents	No
`ListMcpResourcesTool`	Lists resources exposed by connected MCP servers	No
`LSP`	Code intelligence via language servers: jump to definitions, find references, report type errors and warnings. See LSP tool behavior	No
`Monitor`	Runs a command in the background and feeds each output line back to Claude, so it can react to log entries, file changes, or polled status mid-conversation. See Monitor tool	Yes
`NotebookEdit`	Modifies Jupyter notebook cells	Yes
`PowerShell`	Executes PowerShell commands natively. See PowerShell tool for availability	Yes
`Read`	Reads the contents of files	No
`ReadMcpResourceTool`	Reads a specific MCP resource by URI	No
`SendMessage`	Sends a message to an agent team teammate, or resumes a subagent by its agent ID. Stopped subagents auto-resume in the background. Only available when `CLAUDECODEEXPERIMENTALAGENTTEAMS=1` is set	No
`Skill`	Executes a skill within the main conversation	Yes
`TaskCreate`	Creates a new task in the task list	No
`TaskGet`	Retrieves full details for a specific task	No
`TaskList`	Lists all tasks with their current status	No
`TaskOutput`	(Deprecated) Retrieves output from a background task. Prefer `Read` on the task's output file path	No
`TaskStop`	Kills a running background task by ID	No
`TaskUpdate`	Updates task status, dependencies, details, or deletes tasks	No
`TeamCreate`	Creates an agent team with multiple teammates. Only available when `CLAUDECODEEXPERIMENTALAGENTTEAMS=1` is set	No
`TeamDelete`	Disbands an agent team and cleans up teammate processes. Only available when `CLAUDECODEEXPERIMENTALAGENTTEAMS=1` is set	No
`TodoWrite`	Manages the session task checklist. Available in non-interactive mode and the Agent SDK; interactive sessions use TaskCreate, TaskGet, TaskList, and TaskUpdate instead	No
`ToolSearch`	Searches for and loads deferred tools when tool search is enabled	No
`WebFetch`	Fetches content from a specified URL	Yes
`WebSearch`	Performs web searches	Yes
`Write`	Creates or overwrites files	Yes

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 CLAUDEBASHMAINTAINPROJECTWORKING_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 CLAUDEENVFILE 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

<Note>

The Monitor tool requires Claude Code v2.1.98 or later.

</Note>

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 DISABLETELEMETRY or CLAUDECODEDISABLENONESSENTIAL_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 CLAUDECODEUSEPOWERSHELLTOOL=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 CLAUDECODEUSEPOWERSHELLTOOL.
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 CLAUDEBASHMAINTAINPROJECTWORKING_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.

内置工具参考