Use tools in chat

Tools extend chat in Visual Studio Code with specialized functionality for accomplishing specific tasks like searching code, running commands, fetching web content, or invoking APIs. VS Code supports three types of tools: built-in tools, Model Context Protocol (MCP) tools, and extension tools.

This article describes the different types of tools available in VS Code, how to use them in your chat prompts, and how to manage tool invocations and approvals.

Types of tools

VS Code supports three types of tools that you can use in chat:

Enable tools for chat

Before you can use tools in chat, you need to enable them in the Chat view. You can enable or disable tools on a per-request basis by using the tools picker. You can add more tools by installing MCP servers or extensions that contribute tools.

To access the tools picker:

1. Open the Chat view in agent mode.

2. Select the Configure Tools button in the chat input field.

   

3. Select or deselect tools to control which ones are available for the current request.

   Use the search box to filter the list of tools.

When you customize chat with prompt files or custom chat modes, you can specify which tools are available for a given prompt or mode. Learn more about the tool list priority order.

Use tools in your prompts

In agent mode, the agent automatically determines which tools to use from the enabled tools based on your prompt and the context of your request. The agent autonomously chooses and invokes relevant tools as needed to accomplish the task.

You can also explicitly reference tools in your prompts in any chat mode by typing # followed by the tool name. This is useful when you want to ensure a specific tool is used. Type # in the chat input field to see a list of available tools, including built-in tools, MCP tools from installed servers, extension tools, and tool sets.

Examples of explicit tool references:

• "Summarize the content from #fetch https://code.visualstudio.com/updates"
• "How does routing work in Next.js? #githubRepo vercel/next.js"
• "Fix the issues in #problems"
• "Explain the authentication flow #codebase"

Some tools accept parameters directly in the prompt. For example, #fetch requires a URL and #githubRepo requires a repository name.

Tool approval

Before chat runs certain tools, it requests confirmation to continue. This is a security measure because tools can perform actions that modify files, run commands, or access external services.

You can:

• Select Allow to run the tool once
• Use the Allow dropdown to approve the tool for the current session, workspace, or all future invocations
• Select Skip to skip the tool invocation

Reset tool confirmations

To clear all saved tool approvals, use the Chat: Reset Tool Confirmations command in the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)).

Automatically approve terminal commands

You can configure which terminal commands are automatically approved by using the chat.tools.terminal.autoApprove setting. You can specify both allowed and denied commands:

• Set commands to true to automatically approve them
• Set commands to false to always require approval
• Use regular expressions by wrapping patterns in / characters

For example:

{
  // Allow the `mkdir` command
  "mkdir": true,
  // Allow `git status` and commands starting with `git show`
  "/^git (status|show\\b.*)$/": true,

  // Block the `del` command
  "del": false,
  // Block any command containing "dangerous"
  "/dangerous/": false
}

By default, patterns match against individual subcommands. For a command to be auto-approved, all subcommands must match a true entry and must not match a false entry.

For advanced scenarios, use object syntax with the matchCommandLine property to match against the full command line instead of individual subcommands.

Auto-approve all tools

To disable all manual approvals for tools and terminal commands in all workspaces, enable the chat.tools.global.autoApprove setting.

Edit tool parameters

You can review and edit the input parameters before a tool runs:

1. When the tool confirmation dialog appears, select the chevron next to the tool name to expand its details.

2. Edit any tool input parameters as needed.

3. Select Allow to run the tool with the modified parameters.

Group tools with tool sets

A tool set is a collection of tools that you can reference as a single entity in your prompts. Tool sets help you organize related tools and make them easier to use in a chat prompt, prompt files, and custom chat modes. Some of the built-in tools are part of predefined tool sets, such as #edit and #search.

Create a tool set

To create a tool set:

1. Select the Configure Chat button in the Chat view, select Tool Sets, and then select Create new tool sets file.

   Alternatively, use the Chat: Configure Tool Sets command from the Command Palette.

   

2. Define your tool set in the .jsonc file that opens.

   A tool set has the following structure:

   {
     "reader": {
       "tools": ["changes", "codebase", "problems", "usages"],
       "description": "Tools for reading and gathering context",
       "icon": "book"
     }
   }
   

   Tool set properties:

   • tools: Array of tool names (built-in tools, MCP tools, or extension tools)
   • description: Brief description displayed in the tools picker
   • icon: Icon for the tool set (see Product Icon Reference)

Use a tool set

Reference a tool set in your prompts by typing # followed by the tool set name:

• "Analyze the codebase for security issues #reader"
• "Where is the DB connection string defined? #search"

In the tools picker, tool sets are available as collapsible groups of related tools. You can select or deselect entire tool sets to quickly enable or disable multiple related tools at once.

Frequently asked questions

How do I know which tools are available?

Type # in the chat input field to see a list of all available tools. You can also access the tools picker in agent mode to view and manage tools.

I'm getting an error that says "Cannot have more than 128 tools per request."

A chat request can have a maximum of 128 tools enabled at a time. If you see an error about exceeding 128 tools per request:

• Open the tools picker in the Chat view and deselect some tools or entire MCP servers to reduce the count.

• Alternatively, enable virtual tools with the github.copilot.chat.virtualTools.threshold setting to automatically manage large tool sets.

What's the difference between tools and chat participants?

Chat participants are specialized assistants that enable you to ask domain-specific questions in chat. Imagine a chat participant as a domain expert to whom you hand off your chat request and it takes care of the rest.

Tools are invoked as part of an agent flow to contribute and perform specific tasks. You can include multiple tools in a single chat request, but only one chat participant can be active at a time.

Can I create my own tools?

Yes. You can create tools in two ways:

• Develop a VS Code extension that contributes tools using the Language Model Tools API
• Create an MCP server that provides tools. See the MCP developer guide

Related resources

• Chat tools reference
• Security considerations for using AI in VS Code