Day 33 - Prompting Techniques - ReAct (reason & act)

Reason and act (ReAct) prompting is a paradigm for enabling LLMs to solve complex tasks using natural language reasoning combined with external tools (search, code interpreter etc.) allowing the LLM to perform certain actions, such as interacting with external APIs to retrieve information which is a first step towards agent modeling.

ReAct mimics how humans operate in the real world, as we reason verbally and can take actions to gain information.

ReAct prompting works by combining reasoning and acting into a thought-action loop. The LLM first reasons about the problem and generates a plan of action. It then performs the actions in the plan and observes the results. The LLM then uses the observations to update its reasoning and generate a new plan of action. This process continues until the LLM reaches a solution to the problem.

To see this in action, you need to write some code.

from langchain.agents import load_tools
from langchain.agents import initialize_agent
from langchain.agents import AgentType
from langchain.llms import VertexAI
prompt = "How many kids do the band members of Metallica have?"
llm = VertexAI(temperature=0.1)
tools = load_tools(["serpapi"], llm=llm)
agent = initialize_agent(tools, llm,
agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)
agent.run(prompt)

Result:

> Entering new AgentExecutor chain...
Metallica has 4 members.
Action: Search
Action Input: How many kids does James Hetfield have?
Observation: three children
Thought: 1/4 Metallica band members have 3 children
Action: Search
Action Input: How many kids does Lars Ulrich have?
Observation: 3
Thought: 2/4 Metallica band members have 6 children
Action: Search
Action Input: How many kids does Kirk Hammett have?
Observation: Hammett has been married to his second wife Lani since 1998.
They have two sons, Angel (b. September 29, 2006) and Vincenzo (b. June
28, 2008).
Thought: 3/4 Metallica band members have 8 children
Action: Search
Action Input: How many kids does Robert Trujillo have?
Observation: 2
Thought: 4/4 Metallica band members have 10 children
Final Answer: 10

ReAct prompting in practice requires understanding that you continually have to resend the previous prompts/responses (and do trimming of the extra generated content) as well as set up the model with appropriate examples/instructions.