Use tools with agents

Tools extend agents 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.

For background on tool types and how tools work in the agent loop, see Tools concepts.

This article shows how to complete a request with tools, direct the agent to specific tools, control which tools are available, and review tool calls.

Use tools in a request

By default, the agent chooses from the enabled tools based on your request and the current context. You don't need to name or select each tool before you start.

To complete a request with tools:

1. In the chat input, select Agent from the agent picker.

2. Enter a prompt that describes your goal and how the agent should verify its work. For example:

   Find the cause of the failing tests in this project, fix it, and run the relevant tests to verify the change.
   

3. Review each tool call as the agent works. If an approval prompt appears, expand the tool details to review its inputs, and then select Allow to run it.

4. Expand a tool summary in the conversation to inspect the call and its output. When the task is complete, review the agent's response, code changes, and validation results.

To control which calls require approval and how much autonomy the agent has, see Manage approvals and permissions.

Reference a tool explicitly

Type # in the chat input to reference a specific tool or tool set. Use an explicit reference when you want to direct the agent to a particular capability instead of letting it choose.

For example, use the #web/fetch tool to retrieve a specific web page:

Summarize the latest release notes at code.visualstudio.com/updates with #web/fetch.

Use a tool set, such as #web, to make a group of related tools available:

Research how Next.js handles routing. Use #web tools and summarize the relevant guidance.

The # menu also contains context items, such as files, folders, and editor selections. Context items provide information for the request, while tools give the agent capabilities to gather information or take actions. Learn more about adding context to chat prompts.

To group related tools and reuse them across prompts, prompt files, and custom agents, create a tool set.

Select tools for a request

The Local and Copilot harnesses use different controls to select client-side tools.

For either session type, limit the selection to tools that are relevant to your request. Add capabilities by installing MCP servers or extensions that contribute tools.

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

Manage tool availability for Copilot

All client-side tools are available to the Copilot harness by default. In the Tools tab, tools are organized into collapsible groups. You can:

• Enter text in the search box to filter tool groups and individual tools.
• Select a tool group checkbox to enable or disable every tool in the group.
• Expand a group and select individual tools. The group checkbox shows a mixed state when only some tools are enabled.
• Review the enabled and total tool counts shown for each group.

The count beside Tools in the customization navigation includes enabled client-side tools and excludes the read-only tools built into the Copilot harness.

The Copilot group lists the harness's built-in tools. These tools run in the Copilot runtime and are read-only in the Tools tab. Other tools run in the VS Code client and are available to the agent only while the client is connected.

Tool availability is separate from tool approval. Enabling a tool makes it available to the agent, but doesn't bypass the configured approval and permission controls.

Add extension tools for Copilot

In the main VS Code window, you can find extensions that contribute language model tools:

1. Open the Tools tab and select Browse Marketplace.

2. Search for an extension and select it to view its details and contributed tools.

3. Install the extension. Its tools then appear in the tool list, where you can manage their availability.

The Agents window shows the tool availability list but doesn't include Marketplace browsing.

To remove an extension from the tool list, right-click its tool group and select Uninstall Extension.

Edit tool parameters

For a tool call that requires approval, you can review and edit its input parameters before it 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.

Common built-in tool workflows

Use browser tools

Browser tools give agents an interactive way to validate web applications. Instead of inspecting only the source code, an agent can run your app, open it in the integrated browser, exercise a user flow, inspect page content and console errors, and fix problems it discovers.

Browser tools are built into VS Code and don't require an external MCP server. Use them when a task has an observable result in a web interface, such as verifying a form, reproducing a visual bug, checking responsive behavior, or testing a complete user journey.

Start the app, open it in the browser, and test the password reset flow.
Fix any issues you find and repeat the flow to verify the fix.

Learn how to use browser tools with agents, including browser sessions, page sharing, privacy controls, and effective prompting patterns.

Run terminal commands

Of all the built-in tools, the terminal tool is one of the most frequently used. The agent uses it to run commands as part of its workflow, for example to install dependencies, run a build, or execute tests. Because terminal commands can change your environment, VS Code provides additional controls for reviewing, running, and monitoring them, building on the approval behavior described earlier.

When the agent decides to run a command, it uses the built-in terminal tool to execute it in an integrated terminal within VS Code.

In the chat conversation, the agent displays the commands it ran. You can view the output of the command inline in chat by selecting Show Output (>) next to the command. You can also view the full output in the integrated terminal by selecting Show Terminal.

Continue terminal commands in background

When the agent runs a long-running terminal command, such as starting a development server or running a build in watch mode, you can push the command to the background. This allows the agent to continue with other tasks without waiting for the command to finish.

While a command is running, a Continue in Background button appears next to the terminal command in the chat conversation. Select this button to move the command to the background. The command continues running, and the agent can check its output later or use the terminal for other tasks.

The agent can also specify a timeout when running terminal commands. When the timeout is reached, the agent stops waiting for the command and returns the output collected so far. Use the chat.tools.terminal.enforceTimeoutFromModel Open in VS Code Open in VS Code Insiders setting to control whether to enforce the timeout value that the agent specifies.

The agent can also choose to run commands directly in the background, without user interaction. Background terminals that you have not revealed are automatically cleaned up when their command finishes, which prevents stale terminals from accumulating over a long session. To reveal a background terminal and keep it open after the command completes, select the Show link in the chat tool invocation header. The terminal output remains visible in the chat conversation even after a terminal is cleaned up.

Frequently asked questions

Related resources

• Chat tools reference
• Create and use tool sets
• Security considerations for using AI in VS Code