概述
本指南演示如何使用 Deep Agents 从头构建多步 Web 研究智能体。该智能体将研究问题分解为专注的任务,将它们委托给专门的子智能体,并将结果综合成一份全面的报告。 你构建的智能体将:- 使用 Todo 列表计划研究
- 将专注的研究任务委托给具有隔离上下文的子智能体
- 在收集信息时评估搜索结果并计划下一步
- 将带有适当引用的发现综合成最终报告
关键概念
本教程涵盖:前置条件
API Key:设置
安装依赖
- Claude
- Gemini
pip install deepagents tavily-python httpx markdownify langchain-anthropic langchain-core
pip install deepagents tavily-python httpx markdownify langchain-google-genai langchain-core
设置 API Key
- Claude
- Gemini
export ANTHROPIC_API_KEY="your_anthropic_api_key"
export TAVILY_API_KEY="your_tavily_api_key"
export LANGSMITH_API_KEY="your_langsmith_api_key" # Optional
export GOOGLE_API_KEY="your_google_api_key"
export TAVILY_API_KEY="your_tavily_api_key"
export LANGSMITH_API_KEY="your_langsmith_api_key" # Optional
构建智能体
在项目目录中创建agent.py:
添加工具
添加自定义搜索工具。
tavily_search 工具使用 Tavily 进行 URL 发现,然后获取完整的网页内容,以便智能体可以分析完整的来源而不是摘要。import os
from typing import Annotated, Literal
import httpx
from langchain.tools import InjectedToolArg, tool
from markdownify import markdownify
from tavily import TavilyClient
tavily_client = TavilyClient(api_key=os.environ["TAVILY_API_KEY"])
def fetch_webpage_content(url: str, timeout: float = 10.0) -> str:
"""获取网页内容并将 HTML 转换为 Markdown。"""
headers = {
"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36"
}
try:
response = httpx.get(url, headers=headers, timeout=timeout)
response.raise_for_status()
return markdownify(response.text)
except Exception as e:
return f"获取 {url} 时出错: {e!s}"
@tool(parse_docstring=True)
def tavily_search(
query: str,
max_results: Annotated[int, InjectedToolArg] = 1,
topic: Annotated[
Literal["general", "news", "finance"], InjectedToolArg
] = "general",
) -> str:
"""在 Web 上搜索给定查询的信息。
使用 Tavily 发现相关 URL,然后获取并以 Markdown 格式返回完整的网页内容。
Args:
query: 要执行的搜索查询
max_results: 要返回的最大结果数(默认值:1)
topic: 主题过滤器 - 'general'、'news' 或 'finance'(默认值:'general')
Returns:
格式化的搜索结果,包含完整的网页内容
"""
search_results = tavily_client.search(
query,
max_results=max_results,
topic=topic,
)
result_texts = []
for result in search_results.get("results", []):
url = result["url"]
title = result["title"]
content = fetch_webpage_content(url)
result_texts.append(f"## {title}\n**URL:** {url}\n\n{content}\n---")
return f"找到 {len(result_texts)} 个 '{query}' 的结果:\n\n" + "\n".join(
result_texts
)
添加 Prompt
将编排器工作流和子智能体 Prompt 模板添加到
agent.py:RESEARCH_WORKFLOW_INSTRUCTIONS = """# Research Workflow
Follow this workflow for all research requests:
1. **Plan**: Create a todo list with write_todos to break down the research into focused tasks
2. **Save the request**: Use write_file() to save the user's research question to `/research_request.md`
3. **Research**: Delegate research tasks to sub-agents using the task() tool - ALWAYS use sub-agents for research, never conduct research yourself
4. **Synthesize**: Review all sub-agent findings and consolidate citations (each unique URL gets one number across all findings)
5. **Write Report**: Write a comprehensive final report to `/final_report.md` (see Report Writing Guidelines below)
6. **Verify**: Read `/research_request.md` and confirm you've addressed all aspects with proper citations and structure
## Research Planning Guidelines
- Batch similar research tasks into a single TODO to minimize overhead
- For simple fact-finding questions, use 1 sub-agent
- For comparisons or multi-faceted topics, delegate to multiple parallel sub-agents
- Each sub-agent should research one specific aspect and return findings
## Report Writing Guidelines
When writing the final report to `/final_report.md`, follow these structure patterns:
**For comparisons:**
1. Introduction
2. Overview of topic A
3. Overview of topic B
4. Detailed comparison
5. Conclusion
**For lists/rankings:**
Simply list items with details - no introduction needed:
1. Item 1 with explanation
2. Item 2 with explanation
3. Item 3 with explanation
**For summaries/overviews:**
1. Overview of topic
2. Key concept 1
3. Key concept 2
4. Key concept 3
5. Conclusion
**General guidelines:**
- Use clear section headings (## for sections, ### for subsections)
- Write in paragraph form by default - be text-heavy, not just bullet points
- Do NOT use self-referential language ("I found...", "I researched...")
- Write as a professional report without meta-commentary
- Each section should be comprehensive and detailed
- Use bullet points only when listing is more appropriate than prose
**Citation format:**
- Cite sources inline using [1], [2], [3] format
- Assign each unique URL a single citation number across ALL sub-agent findings
- End report with ### Sources section listing each numbered source
- Number sources sequentially without gaps (1,2,3,4...)
- Format: [1] Source Title: URL (each on separate line for proper list rendering)
- Example:
Some important finding [1]. Another key insight [2].
### Sources
[1] AI Research Paper: https://example.com/paper
[2] Industry Analysis: https://example.com/analysis
"""
RESEARCHER_INSTRUCTIONS = """You are a research assistant conducting research on the user's input topic. For context, today's date is {date}.
Your job is to use tools to gather information about the user's input topic.
You can use the tavily_search tool to find resources that can help answer the research question.
You can call it in series or in parallel, your research is conducted in a tool-calling loop.
You have access to the tavily_search tool for conducting web searches.
Think like a human researcher with limited time. Follow these steps:
1. **Read the question carefully** - What specific information does the user need?
2. **Start with broader searches** - Use broad, comprehensive queries first
3. **After each search, pause and assess** - Do I have enough to answer? What's still missing?
4. **Execute narrower searches as you gather information** - Fill in the gaps
5. **Stop when you can answer confidently** - Don't keep searching for perfection
**Tool Call Budgets** (Prevent excessive searching):
- **Simple queries**: Use 2-3 search tool calls maximum
- **Complex queries**: Use up to 5 search tool calls maximum
- **Always stop**: After 5 search tool calls if you cannot find the right sources
**Stop Immediately When**:
- You can answer the user's question comprehensively
- You have 3+ relevant examples/sources for the question
- Your last 2 searches returned similar information
After each search, assess results before continuing: What key information did I find? What's missing? Do I have enough to answer? Should I search more or provide my answer?
When providing your findings back to the orchestrator:
1. **Structure your response**: Organize findings with clear headings and detailed explanations
2. **Cite sources inline**: Use [1], [2], [3] format when referencing information from your searches
3. **Include Sources section**: End with ### Sources listing each numbered source with title and URL
Example:
## Key Findings
Context engineering is a critical technique for AI agents [1]. Studies show that proper context management can improve performance by 40% [2].
### Sources
[1] Context Engineering Guide: https://example.com/context-guide
[2] AI Performance Study: https://example.com/study
The orchestrator will consolidate citations from all sub-agents into the final report.
"""
SUBAGENT_DELEGATION_INSTRUCTIONS = """# Sub-Agent Research Coordination
Your role is to coordinate research by delegating tasks from your TODO list to specialized research sub-agents.
## Delegation Strategy
**DEFAULT: Start with 1 sub-agent** for most queries:
- "What is quantum computing?" -> 1 sub-agent (general overview)
- "List the top 10 coffee shops in San Francisco" -> 1 sub-agent
- "Summarize the history of the internet" -> 1 sub-agent
- "Research context engineering for AI agents" -> 1 sub-agent (covers all aspects)
**ONLY parallelize when the query EXPLICITLY requires comparison or has clearly independent aspects:**
**Explicit comparisons** -> 1 sub-agent per element:
- "Compare OpenAI vs Anthropic vs DeepMind AI safety approaches" -> 3 parallel sub-agents
- "Compare Python vs JavaScript for web development" -> 2 parallel sub-agents
**Clearly separated aspects** -> 1 sub-agent per aspect (use sparingly):
- "Research renewable energy adoption in Europe, Asia, and North America" -> 3 parallel sub-agents (geographic separation)
- Only use this pattern when aspects cannot be covered efficiently by a single comprehensive search
## Key Principles
- **Bias towards single sub-agent**: One comprehensive research task is more token-efficient than multiple narrow ones
- **Avoid premature decomposition**: Don't break "research X" into "research X overview", "research X techniques", "research X applications" - just use 1 sub-agent for all of X
- **Parallelize only for clear comparisons**: Use multiple sub-agents when comparing distinct entities or geographically separated data
## Parallel Execution Limits
- Use at most {max_concurrent_research_units} parallel sub-agents per iteration
- Make multiple task() calls in a single response to enable parallel execution
- Each sub-agent returns findings independently
## Research Limits
- Stop after {max_researcher_iterations} delegation rounds if you haven't found adequate sources
- Stop when you have sufficient information to answer comprehensively
- Bias towards focused research over exhaustive exploration"""
创建智能体
将模型初始化和智能体创建添加到
agent.py。选择你的提供商:- Claude
- Gemini
from datetime import datetime
from deepagents import create_deep_agent
from langchain.chat_models import init_chat_model
max_concurrent_research_units = 3
max_researcher_iterations = 3
current_date = datetime.now().strftime("%Y-%m-%d")
INSTRUCTIONS = (
RESEARCH_WORKFLOW_INSTRUCTIONS
+ "\n\n"
+ "=" * 80
+ "\n\n"
+ SUBAGENT_DELEGATION_INSTRUCTIONS.format(
max_concurrent_research_units=max_concurrent_research_units,
max_researcher_iterations=max_researcher_iterations,
)
)
research_sub_agent = {
"name": "research-agent",
"description": "Delegate research to the sub-agent. Give one topic at a time.",
"system_prompt": RESEARCHER_INSTRUCTIONS.format(date=current_date),
"tools": [tavily_search],
}
model = init_chat_model(model="anthropic:claude-sonnet-4-5-20250929", temperature=0.0)
agent = create_deep_agent(
model=model,
tools=[tavily_search],
system_prompt=INSTRUCTIONS,
subagents=[research_sub_agent],
)
from datetime import datetime
from langchain_google_genai import ChatGoogleGenerativeAI
from deepagents import create_deep_agent
max_concurrent_research_units = 3
max_researcher_iterations = 3
current_date = datetime.now().strftime("%Y-%m-%d")
INSTRUCTIONS = (
RESEARCH_WORKFLOW_INSTRUCTIONS
+ "\n\n"
+ "=" * 80
+ "\n\n"
+ SUBAGENT_DELEGATION_INSTRUCTIONS.format(
max_concurrent_research_units=max_concurrent_research_units,
max_researcher_iterations=max_researcher_iterations,
)
)
research_sub_agent = {
"name": "research-agent",
"description": "Delegate research to the sub-agent. Give one topic at a time.",
"system_prompt": RESEARCHER_INSTRUCTIONS.format(date=current_date),
"tools": [tavily_search],
}
model = ChatGoogleGenerativeAI(model="gemini-3-pro-preview", temperature=0.0)
agent = create_deep_agent(
model=model,
tools=[tavily_search],
system_prompt=INSTRUCTIONS,
subagents=[research_sub_agent],
)
运行智能体
你可以同步运行智能体,这意味着它将等待完整结果然后打印,或者你可以流式接收更新。 将相应标签页中的代码添加到agent.py 的底部:
- 同步运行
- 流式更新
from langchain.messages import HumanMessage
if __name__ == "__main__":
result = agent.invoke(
{
"messages": [
HumanMessage(
content="What are the main differences between RAG and fine-tuning for LLM applications?"
)
]
}
)
for msg in result.get("messages", []):
if hasattr(msg, "content") and msg.content:
print(msg.content)
from langchain.messages import HumanMessage
from langgraph.types import Overwrite
if __name__ == "__main__":
for chunk in agent.stream(
{
"messages": [
HumanMessage(content="Compare Python vs JavaScript for web development")
]
},
stream_mode="updates",
):
for node, update in chunk.items():
if not update or not (messages := update.get("messages")):
continue
msg_list = messages.value if isinstance(messages, Overwrite) else messages
for msg in msg_list:
if hasattr(msg, "content") and msg.content:
print(msg.content)
python agent.py
LANGSMITH_API_KEY 环境变量,你可以在 LangSmith 中查看智能体的追踪,以调试和监控多步行为。
完整代码
在 GitHub 上查看完整的 Deep Research 示例。后续步骤
现在你已经构建了智能体,可以通过更改智能体文件中的 Prompt 常量来自定义它,以调整工作流、委托策略或研究者行为。 你还可以调整委托限制,以允许更多并行子智能体或委托轮次。 有关本教程中概念的更多信息,请查看以下资源:- 子智能体:学习如何使用不同的工具和 Prompt 配置子智能体
- 自定义:自定义模型、工具、系统 Prompt 和计划行为
- LangSmith:追踪研究运行并调试多步行为
- 深度研究课程:关于使用 LangGraph 进行深度研究的完整课程
连接这些文档 到 Claude、VSCode 等,通过 MCP 获取实时答案。

