Web Fetch

Web fetch 工具可讓 LLM 從指定的網頁和 PDF 文件擷取完整內容。這使 AI 模型能從網際網路存取即時資訊，並將網頁內容納入其回應中。

Web Fetch 與 Web Search

Web Fetch 會從您提供 URL 的特定網頁擷取完整內容，而 Web Search 則會進行網際網路搜尋，根據您的查詢尋找相關資訊。

功能	Web Fetch	Web Search
用途	從特定 URL 擷取內容	搜尋網際網路上的資訊
輸入	您提供要擷取的精確 URL	您提供搜尋查詢／問題
輸出	來自指定 URL 的完整頁面內容	含有相關資訊的搜尋結果
使用情境	- 分析特定文章 - 比較已知網站的內容 - 從特定頁面擷取資料	- 尋找最新新聞／事件 - 研究主題 - 取得即時資訊

Web Fetch 範例： "從 https://example.com/pricing 擷取內容並摘要"
Web Search 範例： "本週最新的 AI 發展有哪些？"

支援的提供者：

• Anthropic API (anthropic/)

支援的工具類型：

• web_fetch_20250910 - 具有限制使用量、網域篩選與引用支援的網頁內容擷取工具

快速開始

LiteLLM Python SDK

import os 
from litellm import completion

os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

# Web fetch tool
tools = [
    {
        "type": "web_fetch_20250910",
        "name": "web_fetch",
        "max_uses": 5,
    }
]

messages = [
    {
        "role": "user", 
        "content": "Please analyze the content at https://example.com/article and summarize the main points"
    }
]

response = completion(
    model="anthropic/claude-3-5-sonnet-latest",
    messages=messages,
    tools=tools,
)

print(response)

LiteLLM 代理閘道

1. 在 config.yaml 中定義 web fetch 模型

model_list:
  - model_name: claude-3-5-sonnet-latest # Anthropic claude-3-5-sonnet-latest
    litellm_params:
      model: anthropic/claude-3-5-sonnet-latest
      api_key: os.environ/ANTHROPIC_API_KEY

2. 執行 proxy 伺服器

litellm --config config.yaml

3. 使用 OpenAI Python SDK 進行測試

import os 
from openai import OpenAI

client = OpenAI(
    api_key="sk-1234", # your litellm proxy api key
    base_url="http://0.0.0.0:4000"
)

response = client.chat.completions.create(
    model="claude-3-5-sonnet-latest",
    messages=[
        {
            "role": "user", 
            "content": "Please fetch and analyze the content from https://news.ycombinator.com and tell me about the top stories"
        }
    ],
    tools=[
        {
            "type": "web_fetch_20250910",
            "name": "web_fetch",
            "max_uses": 5,
        }
    ]
)

print(response)

支援的模型

web fetch 可用於以下 Anthropic API 模型：

• claude-opus-4-6 (Claude Opus 4.6)
• claude-sonnet-4-6 (Claude Sonnet 4.6)
• claude-opus-4-5 (Claude Opus 4.5)
• claude-sonnet-4-5 (Claude Sonnet 4.5)
• claude-haiku-4-5 (Claude Haiku 4.5)
• claude-opus-4-1-20250805 (Claude Opus 4.1)
• claude-opus-4-20250514 (Claude Opus 4)
• claude-sonnet-4-20250514 (Claude Sonnet 4)
• claude-3-7-sonnet-20250219 (Claude Sonnet 3.7)
• claude-3-5-sonnet-latest (Claude Sonnet 3.5 v2 - deprecated)
• claude-3-5-haiku-latest (Claude Haiku 3.5)

備註

目前 web fetch 工具不支援透過 JavaScript 動態渲染的網站。

使用範例

基本網頁內容擷取

import os 
from litellm import completion

os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

tools = [
    {
        "type": "web_fetch_20250910",
        "name": "web_fetch",
        "max_uses": 3,
    }
]

messages = [
    {
        "role": "user",
        "content": "Fetch the latest news from https://techcrunch.com and summarize the top 3 articles"
    }
]

response = completion(
    model="anthropic/claude-3-5-sonnet-latest",
    messages=messages,
    tools=tools,
)

print(response)

研究與分析

import os 
from litellm import completion

os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

tools = [
    {
        "type": "web_fetch_20250910",
        "name": "web_fetch", 
        "max_uses": 10,
    }
]

messages = [
    {
        "role": "user",
        "content": "Research the latest developments in AI by fetching content from multiple tech news websites and provide a comprehensive analysis"
    }
]

response = completion(
    model="anthropic/claude-3-5-sonnet-latest",
    messages=messages,
    tools=tools,
)

print(response)

內容比較

import os 
from litellm import completion

os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

tools = [
    {
        "type": "web_fetch_20250910",
        "name": "web_fetch",
        "max_uses": 5,
    }
]

messages = [
    {
        "role": "user",
        "content": "Compare the pricing information from https://openai.com/pricing and https://anthropic.com/pricing and create a comparison table"
    }
]

response = completion(
    model="anthropic/claude-3-5-sonnet-latest",
    messages=messages,
    tools=tools,
)

print(response)

結合多種工具的進階用法

您可以將 web fetch 與其他工具結合，例如 computer use 或 text editor：

import os 
from litellm import completion

os.environ["ANTHROPIC_API_KEY"] = "your-api-key"

tools = [
    {
        "type": "web_fetch_20250910",
        "name": "web_fetch",
        "max_uses": 5,
    },
    {
        "type": "text_editor_20250124", 
        "name": "str_replace_editor"
    }
]

messages = [
    {
        "role": "user",
        "content": "Fetch the latest AI research papers from arXiv, analyze them, and create a detailed report file with your findings"
    }
]
    
response = completion(
    model="anthropic/claude-3-5-sonnet-latest",
    messages=messages,
    tools=tools,
)

print(response)

規格

Web Fetch 工具 (web_fetch_20250910)

web fetch 工具支援以下參數：

{
  "type": "web_fetch_20250910",
  "name": "web_fetch",

  // Optional: Limit the number of fetches per request
  "max_uses": 10,

  // Optional: Only fetch from these domains
  "allowed_domains": ["example.com", "docs.example.com"],

  // Optional: Never fetch from these domains
  "blocked_domains": ["private.example.com"],

  // Optional: Enable citations for fetched content
  "citations": {
    "enabled": true
  },

  // Optional: Maximum content length in tokens
  "max_content_tokens": 100000
}