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AI Agents with LangChain & Autonomous Workflows · レッスン

エージェントの思考プロセスのデバッグ

体系的なアプローチを適用し、エージェントの推論や行動シーケンスにある問題を特定・解決します。

「エージェントの思考プロセスのデバッグ」はCoddyKit上の無料AI Agents with LangChain & Autonomous Workflowsレッスンです。 これはレッスン2/4です。 下記で完全なレッスンを無料で読むことができます。その後、ブラウザ内の組み込みコードエディタと24時間対応のAIチューターでハンズオン演習できます。 これはAI Agents with LangChain & Autonomous Workflows学習パスの一部であり、ウェブとCoddyKitアプリ全体で進捗が同期されます。 AI Agents with LangChain & Autonomous Workflowsコースには全4レッスンが含まれています。

このレッスンの一部はまだ翻訳されておらず、英語で表示されています。

Debugging Agent Thoughts

Ever had an AI agent give a weird answer or get stuck? Debugging agents isn't like debugging regular code. Instead of just finding syntax errors, we need to understand the agent's "thought process".

This lesson will teach you how to peek into your agent's mind to see why it makes certain decisions and how to fix its reasoning.

The Agent's Inner Voice

An AI agent doesn't just output a final answer. Internally, it goes through a series of "thoughts". These thoughts involve:

  • Reasoning: What's the best next step?
  • Tool Selection: Which tool should I use?
  • Tool Input: What input should I give the tool?
  • Observation: What was the result of using the tool?

By examining this sequence, we can pinpoint where the agent's logic might be failing.

Common Agent Issues

Agents can fail in several ways beyond simple code bugs:

  • Wrong Tool: Selecting an irrelevant tool for the task.
  • Bad Tool Input: Providing incorrect or malformed input to a tool.
  • Reasoning Errors: Misinterpreting the problem or tool observations.
  • Infinite Loops: Getting stuck in a repetitive cycle of thoughts and actions.
  • Hallucinations: Making up facts or confidentially incorrect information.

Understanding these helps you know what to look for.

Seeing Agent Steps with Verbose

LangChain provides a simple way to see an agent's internal steps: the verbose=True parameter. When you set this, the agent will print its entire thought process to the console as it executes.

This "log" includes every Thought, Action, Action Input, and Observation, giving you a complete picture of its decision-making journey.

Tracing a Basic Agent

Let's see verbose=True in action. This agent uses a simple tool to get information. Pay attention to the output in the console!

Note: This code requires an OpenAI API key. Set OPENAI_API_KEY as an environment variable or uncomment and replace "YOUR_KEY".

import os
from langchain_openai import ChatOpenAI
from langchain.agents import AgentExecutor, create_react_agent, Tool
from langchain import hub # For standard prompts

# 1. Define a simple tool
def get_info(topic: str) -> str:
    """Provides info on simple topics."""
    if "python" in topic.lower():
        return "Python is a popular language."
    elif "agent" in topic.lower():
        return "An agent uses an LLM to decide actions."
    return f"No specific info for '{topic}'."

tools = [
    Tool(
        name="info_tool",
        func=get_info,
        description="Useful for getting basic info on a topic.",
    ),
]

# 2. Set up the LLM (requires OPENAI_API_KEY)
# os.environ["OPENAI_API_KEY"] = "YOUR_KEY"
llm = ChatOpenAI(temperature=0, model="gpt-3.5-turbo")

# 3. Get the standard ReAct prompt
prompt = hub.pull("hwchase17/react")

# 4. Create the agent
agent = create_react_agent(llm, tools, prompt)

# 5. Create an agent executor with verbose logging
agent_executor = AgentExecutor(agent=agent, tools=tools, verbose=True)

# 6. Run the agent to see its thought process
agent_executor.invoke({"input": "What is an agent?"})

Decoding Agent Logs

The verbose output shows a clear sequence:

  • > Entering new AgentExecutor chain...: Agent starts.
  • Thought:: The LLM's reasoning for the next step.
  • Action:: The name of the tool chosen.
  • Action Input:: The arguments passed to the tool.
  • Observation:: The result returned by the tool.
  • Final Answer:: The agent's final response after its thoughts.

This structure is your roadmap for debugging!

Wrong Tool for the Job?

One common issue is the agent selecting the wrong tool or providing bad input. Look at the Action: and Action Input: lines.

  • Did it pick a tool that doesn't fit the query?
  • Did it extract the wrong information from the query to pass to the tool?

If so, you might need to refine your tool's description or adjust the agent's main prompt to guide it better.

Fixing Agent's Logic

If the agent's Thought: itself seems off, it's a reasoning problem. The LLM might be:

  • Misunderstanding the overall goal.
  • Failing to incorporate previous Observations:.
  • Struggling with complex instructions.

To fix this, clarify the agent's system prompt, provide more context, or break down complex tasks into simpler sub-tasks.

Breaking the Loop

An agent stuck in an infinite loop will repeatedly generate similar Thought:, Action:, and Observation: sequences without progressing to a Final Answer:.

Common causes include:

  • Ambiguous tool descriptions.
  • Tools returning unhelpful or identical results.
  • Prompts that don't clearly define a "completion" state.

Refine tool descriptions, ensure tools provide distinct outputs, or add explicit stopping conditions to your prompt.

Spot the Bug!

An agent is designed to summarize text. Here's a snippet of its verbose trace when asked to summarize "The quick brown fox jumps over the lazy dog":

Thought: I need to summarize the text.
Action: text_summarizer_tool
Action Input: What is the weather like?
Observation: The weather is sunny.
Thought: I need to summarize the text.
Action: text_summarizer_tool
Action Input: What is the weather like?
Observation: The weather is sunny.

What is the primary debugging issue here?

Debugging Agents: Key Takeaways

Congratulations! You've learned how to systematically debug your AI agents. Key points:

  • Use verbose=True to expose the agent's internal thought process.
  • Examine Thought, Action, Action Input, and Observation.
  • Identify issues with tool selection, tool input, or the LLM's reasoning.
  • Address infinite loops by refining prompts, tool descriptions, or tool outputs.

Happy debugging, and build more robust agents!

よくある質問

「エージェントの思考プロセスのデバッグ」レッスンは無料ですか？

はい。「エージェントの思考プロセスのデバッグ」の完全なテキストはこのウェブで無料で読めます。インタラクティブに演習し（組み込みコードエディタと24時間対応のAIチューター）、AI Agents with LangChain & Autonomous Workflowsコースの残りをアンロックするには、CoddyKit PROにアップグレードしてください。 AI Agents with LangChain & Autonomous Workflowsコースには全4レッスンが含まれています。

「エージェントの思考プロセスのデバッグ」で何を学びますか？

体系的なアプローチを適用し、エージェントの推論や行動シーケンスにある問題を特定・解決します。 ブラウザで直接実行するハンズオンコードでAI Agents with LangChain & Autonomous Workflowsを演習し、24時間対応のAIチューターがレッスンを進める中での質問に答えます。

AI Agents with LangChain & Autonomous Workflowsを始めるのに経験は必要ですか？

事前経験は必要ありません。CoddyKitのAI Agents with LangChain & Autonomous Workflowsは初級者から上級者向けに構成されているため、ここから始めるか最初から始めて、自分のペースで進むことができます。 これはレッスン2/4です。

「エージェントの思考プロセスのデバッグ」レッスンにはどのくらい時間がかかりますか？

ほとんどのCoddyKitレッスンは約5～10分かかります。各レッスンはコンパクトでインタラクティブなので、着実に進歩し、ウェブとアプリ全体で正確に前回の場所から再開できます。

このAI Agents with LangChain & Autonomous Workflowsレッスンでコードを書いて実行できますか？

はい。すべてのAI Agents with LangChain & Autonomous Workflowsレッスンに組み込みコードエディタが含まれているため、ブラウザでリアルコードを書いて実行し、即座のAIフィードバックを取得できます。ローカル設定は不要です。

このコースのすべてのレッスン

  1. トレーシングと監視のためのLangSmith
  2. エージェントの思考プロセスのデバッグ
  3. エージェントのパフォーマンス評価
  4. トークン使用量とコストの監視
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