ReAct pattern (Reasoning + Acting) in Agentic AI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the ReAct agent with an initial prompt.

Agentic AI

agent = ReActAgent(prompt=[1])

Drag options to blanks, or click blank then click option'

A"Think step-by-step and then act."

B"What is the weather today?"

C"Calculate the sum of 2 and 3."

D"Hello, how are you?"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a simple question as the prompt instead of a reasoning instruction.

The ReAct pattern starts with a prompt that encourages reasoning before acting, such as 'Think step-by-step and then act.'

2fill in blank

medium

Complete the code to make the agent perform an action after reasoning.

Agentic AI

response = agent.[1](input_text)

Drag options to blanks, or click blank then click option'

Athink

Brun

Cact

Dprocess

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'think' instead of 'act' to perform the action.

In the ReAct pattern, the agent acts on the input after reasoning, so the method to perform is 'act'.

3fill in blank

hard

Fix the error in the reasoning step method call.

Agentic AI

thought = agent.[1](context)

Drag options to blanks, or click blank then click option'

Areason

Bthink

Crespond

Dact

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'act' or 'reason' which are not the exact method names.

The correct method for the reasoning step in ReAct is 'think', which returns the agent's thought process.

4fill in blank

hard

Fill both blanks to create a loop that alternates reasoning and acting until done.

Agentic AI

while not done:
    thought = agent.[1](input_data)
    action = agent.[2](thought)

Drag options to blanks, or click blank then click option'

Athink

Bact

Crun

Dprocess

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the order of 'think' and 'act'.

Using incorrect method names like 'run' or 'process'.

The loop first calls 'think' to reason, then 'act' to perform the action, repeating until done.

5fill in blank

hard

Fill all three blanks to store thoughts, actions, and results in a dictionary.

Agentic AI

log = {
    'thought': agent.[1](query),
    'action': agent.[2](query),
    'result': agent.[3](query)
}

Drag options to blanks, or click blank then click option'

Athink

Bact

Cobserve

Drespond

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'respond' instead of 'observe' for the result.

Mixing up the order of methods.

The ReAct pattern uses 'think' for reasoning, 'act' for actions, and 'observe' to get results from the environment.

Practice

1. What is the main purpose of the ReAct pattern in AI problem solving?

easy

A. To store large datasets efficiently

B. To speed up training of neural networks

C. To combine reasoning steps with actions for clearer problem solving

D. To replace human decision making completely

Solution

1. Step 1: Understand the ReAct pattern components

   The ReAct pattern mixes reasoning (thought) and acting (actions) to solve problems step-by-step.

2. Step 2: Identify the main goal

   Its goal is to help AI explain its reasoning clearly while using tools effectively.

3. Final Answer:

   To combine reasoning steps with actions for clearer problem solving -> Option C

4. Quick Check:

   ReAct = Reasoning + Acting [OK]

Hint: ReAct means think and do together for better answers [OK]

Common Mistakes:

• Confusing ReAct with data storage methods
• Thinking it speeds up training only
• Believing it replaces humans fully

2. Which of the following shows the correct sequence of steps in the ReAct pattern?

easy

A. Action -> Thought -> Observation -> Final Answer

B. Thought -> Action -> Observation -> Final Answer

C. Observation -> Thought -> Action -> Final Answer

D. Final Answer -> Thought -> Action -> Observation

Solution

1. Step 1: Recall the ReAct step order

   The ReAct pattern follows Thought (reasoning), then Action (doing), then Observation (seeing results), and finally Final Answer.

2. Step 2: Match the correct sequence

   Thought -> Action -> Observation -> Final Answer matches this exact order.

3. Final Answer:

   Thought -> Action -> Observation -> Final Answer -> Option B

4. Quick Check:

   Step order = Thought, Action, Observation, Final Answer [OK]

Hint: Remember: Think first, then do, then check, then answer [OK]

Common Mistakes:

• Swapping Action and Thought order
• Placing Final Answer too early
• Confusing Observation with Action

3. Given this simplified ReAct code snippet, what will be the final answer output?

thought = "Check if number is even"
action = "Divide number by 2"
observation = 4 / 2
final_answer = "Number is even" if observation == 2 else "Number is odd"
print(final_answer)

medium

A. None

B. Number is odd

C. Error: division by zero

D. Number is even

Solution

1. Step 1: Evaluate the action and observation

   The action divides 4 by 2, resulting in observation = 2.

2. Step 2: Determine the final answer based on observation

   Since observation == 2, the final answer is "Number is even".

3. Final Answer:

   Number is even -> Option D

4. Quick Check:

   4 / 2 = 2 -> even number [OK]

Hint: Check the observation value to decide final answer [OK]

Common Mistakes:

• Confusing observation value with input number
• Assuming division error
• Ignoring the if-else condition

4. Identify the error in this ReAct pattern snippet:

thought = "Find square root"
action = "Calculate sqrt of 16"
observation = sqrt(16)
final_answer = "Square root is " + observation
print(final_answer)

medium

A. Missing import for sqrt function

B. Incorrect string concatenation with number

C. Wrong variable name for observation

D. No error, code runs fine

Solution

1. Step 1: Check usage of sqrt function

   The code uses sqrt(16) but does not import sqrt from math module.

2. Step 2: Identify missing import causing error

   Without 'from math import sqrt', this will cause a NameError.

3. Final Answer:

   Missing import for sqrt function -> Option A

4. Quick Check:

   sqrt needs import from math [OK]

Hint: Always import math functions before use [OK]

Common Mistakes:

• Assuming string concatenation error
• Thinking variable names are wrong
• Believing code runs without imports

5. You want an AI agent using the ReAct pattern to answer: "Is 15 a prime number?" Which sequence best shows how the agent should reason and act?

hard

A. Thought: Check divisibility from 2 to 14 -> Action: Test divisibility by 3 -> Observation: 15 divisible by 3 -> Final Answer: Not prime

B. Thought: Check if 15 is even -> Action: Divide by 2 -> Observation: Not divisible -> Final Answer: Prime

C. Thought: Check if 15 is greater than 10 -> Action: Return yes -> Observation: None -> Final Answer: Prime

D. Thought: Guess number is prime -> Action: Return prime -> Observation: None -> Final Answer: Prime

Solution

1. Step 1: Understand prime checking logic

   To check if 15 is prime, test divisibility by numbers from 2 up to 14.

2. Step 2: Follow ReAct steps correctly

   The agent thinks about divisibility, acts by testing 3, observes 15 is divisible, then concludes not prime.

3. Final Answer:

   Thought: Check divisibility from 2 to 14 -> Action: Test divisibility by 3 -> Observation: 15 divisible by 3 -> Final Answer: Not prime -> Option A

4. Quick Check:

   Divisible by 3 means not prime [OK]

Hint: Test divisors stepwise to confirm prime status [OK]

Common Mistakes:

• Only checking even divisibility
• Guessing without testing
• Ignoring observations in reasoning