用例(User Case)
通用代理评估 (Generic Agent Evaluation)

LangChain

通用代理评估 Generic Agent Evaluation #

良好的评估是快速迭代代理提示和工具的关键。在这里,我们提供了一个如何使用TrajectoryEvalChain来评估您的agent的示例。

设置 Setup #

我们从定义我们的代理开始。

from langchain import Wikipedia
from langchain.chat_models import ChatOpenAI
from langchain.agents import initialize_agent, Tool
from langchain.agents import AgentType
from langchain.agents.react.base import DocstoreExplorer
from langchain.memory import ConversationBufferMemory
from langchain import LLMMathChain
from langchain.llms import OpenAI
 
from langchain import SerpAPIWrapper
 
docstore = DocstoreExplorer(Wikipedia())
 
math_llm = OpenAI(temperature=0)
 
llm_math_chain = LLMMathChain(llm=math_llm, verbose=True)
 
search = SerpAPIWrapper()
 
tools = [
    Tool(
        name="Search",
        func=docstore.search,
        description="useful for when you need to ask with search",
    ),
    Tool(
        name="Lookup",
        func=docstore.lookup,
        description="useful for when you need to ask with lookup",
    ),
    Tool(
        name="Calculator",
        func=llm_math_chain.run,
        description="useful for doing calculations",
    ),
    Tool(
        name="Search the Web (SerpAPI)",
        func=search.run,
        description="useful for when you need to answer questions about current events",
    ),
]
 
memory = ConversationBufferMemory(
    memory_key="chat_history", return_messages=True, output_key="output"
)
 
llm = ChatOpenAI(temperature=0, model_name="gpt-3.5-turbo")
 
agent = initialize_agent(
    tools,
    llm,
    agent=AgentType.CHAT_CONVERSATIONAL_REACT_DESCRIPTION,
    verbose=True,
    memory=memory,
    return_intermediate_steps=True, # This is needed for the evaluation later
)

测试代理 Testing the Agent #

现在让我们在一些示例查询上试用我们的代理。

query_one = "How many ping pong balls would it take to fill the entire Empire State Building?"
 
test_outputs_one = agent({"input": query_one}, return_only_outputs=False)
 
 
> Entering new AgentExecutor chain...
{
    "action": "Search the Web (SerpAPI)",
    "action_input": "How many ping pong balls would it take to fill the entire Empire State Building?"
}
Observation: 12.8 billion. The volume of the Empire State Building Googles in at around 37 million ft³. A golf ball comes in at about 2.5 in³.
Thought:{
    "action": "Final Answer",
    "action_input": "It would take approximately 12.8 billion ping pong balls to fill the entire Empire State Building."
}
 
> Finished chain.
 

这看起来不错!让我们在另一个查询上尝试一下。

query_two = "If you laid the Eiffel Tower end to end, how many would you need cover the US from coast to coast?"
 
test_outputs_two = agent({"input": query_two}, return_only_outputs=False)
 

情况不妙我们来做个评估。

评估代理 Evaluating the Agent #

让我们从定义TrajectoryEvalChain开始。

from langchain.evaluation.agents import TrajectoryEvalChain
 
# Define chain
eval_chain = TrajectoryEvalChain.from_llm(
    llm=ChatOpenAI(temperature=0, model_name="gpt-4"), # Note: This must be a ChatOpenAI model
    agent_tools=agent.tools,
    return_reasoning=True,
)

让我们尝试计算第一个查询。

question, steps, answer = test_outputs_one["input"], test_outputs_one["intermediate_steps"], test_outputs_one["output"]
 
evaluation = eval_chain(
    inputs={"question": question, "answer": answer, "agent_trajectory": eval_chain.get_agent_trajectory(steps)},
)
 
print("Score from 1 to 5: ", evaluation["score"])
print("Reasoning: ", evaluation["reasoning"])
Score from 1 to 5:  1
Reasoning:  First, let's evaluate the final answer. The final answer is incorrect because it uses the volume of golf balls instead of ping pong balls. The answer is not helpful.
 
Second, does the model use a logical sequence of tools to answer the question? The model only used one tool, which was the Search the Web (SerpAPI). It did not use the Calculator tool to calculate the correct volume of ping pong balls.
 
Third, does the AI language model use the tools in a helpful way? The model used the Search the Web (SerpAPI) tool, but the output was not helpful because it provided information about golf balls instead of ping pong balls.
 
Fourth, does the AI language model use too many steps to answer the question? The model used only one step, which is not too many. However, it should have used more steps to provide a correct answer.
 
Fifth, are the appropriate tools used to answer the question? The model should have used the Search tool to find the volume of the Empire State Building and the volume of a ping pong ball. Then, it should have used the Calculator tool to calculate the number of ping pong balls needed to fill the building.
 
Judgment: Given the incorrect final answer and the inappropriate use of tools, we give the model a score of 1.

这似乎是正确的。让我们试试第二个查询。

question, steps, answer = test_outputs_two["input"], test_outputs_two["intermediate_steps"], test_outputs_two["output"]
 
evaluation = eval_chain(
    inputs={"question": question, "answer": answer, "agent_trajectory": eval_chain.get_agent_trajectory(steps)},
)
 
print("Score from 1 to 5: ", evaluation["score"])
print("Reasoning: ", evaluation["reasoning"])
Score from 1 to 5:  3
Reasoning:  i. Is the final answer helpful?
Yes, the final answer is helpful as it provides an approximate number of Eiffel Towers needed to cover the US from coast to coast.
 
ii. Does the AI language use a logical sequence of tools to answer the question?
No, the AI language model does not use a logical sequence of tools. It directly uses the Calculator tool without first using the Search or Lookup tools to find the necessary information (length of the Eiffel Tower and distance from coast to coast in the US).
 
iii. Does the AI language model use the tools in a helpful way?
The AI language model uses the Calculator tool in a helpful way to perform the calculation, but it should have used the Search or Lookup tools first to find the required information.
 
iv. Does the AI language model use too many steps to answer the question?
No, the AI language model does not use too many steps. However, it repeats the same step twice, which is unnecessary.
 
v. Are the appropriate tools used to answer the question?
Not entirely. The AI language model should have used the Search or Lookup tools to find the required information before using the Calculator tool.
 
Given the above evaluation, the AI language model's performance can be scored as follows:
 

这听起来也是对的。总之,TrajectoryEvalChain允许我们使用GPT-4来对我们的智能体的输出和工具使用进行评分,并为我们提供评估背后的推理。