> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/instructkr/claude-code/llms.txt
> Use this file to discover all available pages before exploring further.

# Web tools

> Tools for fetching URL content and searching the web. Covers WebFetchTool and WebSearchTool.

Claude Code provides two web tools: `WebFetchTool` for retrieving content from a specific URL, and `WebSearchTool` for running a web search query. Both tools require permission — by default, Claude will ask you to approve each domain or search the first time it is used.

## WebFetchTool

Fetches content from a URL and returns it to Claude, converting the response to the requested format (markdown by default).

### Parameters

<ParamField path="url" type="string" required>
  The URL to fetch. Must be a valid URL. HTTP URLs are automatically upgraded to HTTPS.
</ParamField>

<ParamField path="prompt" type="string" required>
  A description of what Claude should extract or summarize from the fetched content. The tool applies a lightweight extraction step to focus the result on what you asked for rather than returning the raw page.
</ParamField>

### How it works

1. Claude sends an HTTPS request to the URL.
2. The response body is converted to markdown (stripping HTML tags and formatting).
3. If `prompt` is provided, a lightweight summarization step focuses the content on the relevant parts.
4. The result is returned to Claude as a tool result, capped at 100,000 characters.

### Redirect handling

If the URL redirects to a different host, `WebFetchTool` returns a redirect notice instead of following it automatically. The notice includes the redirect URL so Claude can make a second call with the correct address.

### Supported content types

| Content type          | Handling                                                       |
| --------------------- | -------------------------------------------------------------- |
| HTML pages            | Converted to markdown; scripts and styles removed              |
| Markdown files        | Returned as-is for pre-approved hosts                          |
| PDFs and binary files | Saved to a temporary file on disk; path included in the result |

<Warning>
  `WebFetchTool` cannot access authenticated or private URLs (Google Docs, Confluence, Jira, private GitHub repos, etc.). For authenticated sources, use a specialized MCP server that provides authenticated access instead.
</Warning>

### Permission model

The first time Claude tries to fetch from a domain, it asks for your approval. You can pre-approve domains in your local settings:

```json theme={null}
{
  "permissions": {
    "allow": [
      "WebFetchTool(domain:docs.anthropic.com)",
      "WebFetchTool(domain:github.com)"
    ]
  }
}
```

Some domains are pre-approved (Anthropic documentation, common package registries). Claude does not need to ask for these.

### Example

```
User: What parameters does the Anthropic Messages API accept?

Claude: I'll fetch the API reference.
[WebFetchTool: {
  "url": "https://docs.anthropic.com/en/api/messages",
  "prompt": "List all parameters for the Messages API endpoint with their types and descriptions."
}]
```

***

## WebSearchTool

Searches the web using Anthropic's built-in search capability and returns results with titles, URLs, and a synthesized summary.

<Info>
  `WebSearchTool` is available on Anthropic's first-party API (`claude.ai`) and on Vertex AI with Claude 4.0+ models. It is not available on Amazon Bedrock or with older model versions.
</Info>

### Parameters

<ParamField path="query" type="string" required>
  The search query. Must be at least 2 characters.
</ParamField>

<ParamField path="allowed_domains" type="string[]">
  When provided, only return results from these domains. Cannot be used together with `blocked_domains`.
</ParamField>

<ParamField path="blocked_domains" type="string[]">
  When provided, exclude results from these domains. Cannot be used together with `allowed_domains`.
</ParamField>

### How it works

`WebSearchTool` delegates to Anthropic's server-side web search capability, which runs up to 8 searches internally. The results — titles, URLs, and synthesized commentary — are returned as a structured result. Claude is required to include source links in its response when using web search results.

### Use cases

* Looking up documentation for a library or API.
* Finding the current version of a package.
* Researching error messages or known issues.
* Checking whether a feature is available in a specific version.

### Example

```
User: What's the latest stable version of Bun?

Claude: Let me search for that.
[WebSearchTool: { "query": "Bun latest stable release version 2025" }]
→ Web search results for query: "Bun latest stable release version 2025"
  Bun v1.2.x is the current stable release...
  Links: [{ "title": "Bun releases", "url": "https://bun.sh/blog" }, ...]
```

### Domain filtering example

```json theme={null}
// Only search the Node.js documentation
{
  "query": "fs.readFile options encoding",
  "allowed_domains": ["nodejs.org"]
}

// Exclude a noisy domain
{
  "query": "TypeScript strict mode errors",
  "blocked_domains": ["stackoverflow.com"]
}
```

### Permission model

`WebSearchTool` requires explicit permission the first time it is used. You can pre-approve it in your local settings:

```json theme={null}
{
  "permissions": {
    "allow": ["WebSearchTool"]
  }
}
```