Creating tools for agents in LangChain - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Tool class from langchain.tools.

LangChain

from langchain.tools import [1]

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

ATool

BAgent

CChain

DPrompt

Attempts:

3 left

💡 Hint

Common Mistakes

Importing Agent instead of Tool

Using Chain which is unrelated here

Forgetting to import anything

The Tool class is imported from langchain.tools to create custom tools for agents.

2fill in blank

medium

Complete the code to define a simple tool function that returns a greeting.

LangChain

def greet(name: str) -> str:
    return f"Hello, [1]!"

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

Ainput

Buser

Cname

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable not defined in the function

Using the function name inside the string

The function parameter is name, so we use it inside the f-string to greet the user.

3fill in blank

hard

Fix the error in the tool creation by filling the missing argument for the Tool constructor.

LangChain

my_tool = Tool(name="GreetTool", func=greet, description=[1])

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

A123

Bgreet

CNone

D"A tool that greets users"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the function instead of a description string

Passing None or a number instead of a string

The description argument should be a string explaining what the tool does.

4fill in blank

hard

Fill both blanks to create a tool list and initialize an agent with it.

LangChain

tools = [[1]]
agent = initialize_agent(tools=[2], agent_type="zero-shot-react-description")

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

Amy_tool

B[my_tool]

Ctools

D[]

Attempts:

3 left

💡 Hint

Common Mistakes

Using [my_tool] for the first blank (creates nested list)

Using my_tool for the second blank (instead of tools)

The list tools contains my_tool. The agent is initialized with this list.

5fill in blank

hard

Fill all three blanks to define a tool function, create the tool, and add it to the tools list.

LangChain

def [1](query: str) -> str:
    return f"Searching for: {query}"

search_tool = Tool(name="Search", func=[2], description="Searches the web")
tools = [[3]]

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

Asearch

Csearch_tool

Dgreet

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the function and func argument

Adding the function instead of the tool to the list

The function is named search, used as the func in the tool, and the tool is added to the list.

Practice

1. What is the main purpose of creating tools for agents in Langchain?

easy

A. To let agents perform specific tasks easily

B. To make the code run faster

C. To store data permanently

D. To create user interfaces

Solution

1. Step 1: Understand the role of tools in Langchain

   Tools are designed to help agents do tasks by providing specific functions.

2. Step 2: Identify the main benefit

   By using tools, agents can perform tasks more easily and effectively.

3. Final Answer:

   To let agents perform specific tasks easily -> Option A

4. Quick Check:

   Tools help agents do tasks = B [OK]

Hint: Tools help agents do tasks simply and clearly [OK]

Common Mistakes:

• Thinking tools speed up code execution
• Confusing tools with data storage
• Assuming tools create user interfaces

2. Which of the following is the correct way to create a tool in Langchain?

easy

A. tool = Tool(func=search_function)

B. tool = Tool('search', description='Searches data')

C. tool = Tool(name='search', description='Searches data')

D. tool = Tool(name='search', func=search_function, description='Searches data')

Solution

1. Step 1: Check required parameters for Tool

   The Tool constructor needs a name, a function (func), and a description.

2. Step 2: Match parameters with options

   Only tool = Tool(name='search', func=search_function, description='Searches data') provides all three: name, func, and description correctly.

3. Final Answer:

   tool = Tool(name='search', func=search_function, description='Searches data') -> Option D

4. Quick Check:

   Tool needs name, func, description = C [OK]

Hint: Tool needs name, function, and description to work [OK]

Common Mistakes:

• Omitting the function parameter
• Passing parameters in wrong order
• Leaving out the description

3. Given this code snippet, what will be the output when the agent uses the tool?

def greet(name: str) -> str:
    return f"Hello, {name}!"

from langchain.agents import Tool

greet_tool = Tool(name='greet', func=greet, description='Greets a person')

result = greet_tool.func('Alice')
print(result)

medium

A. "greet Alice"

B. "Hello, Alice!"

C. Error: Missing agent call

D. "Hello!"

Solution

1. Step 1: Understand the greet function behavior

   The greet function returns a string "Hello, {name}!" with the given name.

2. Step 2: Check how the tool is used

   The tool calls greet with 'Alice', so it returns "Hello, Alice!" which is printed.

3. Final Answer:

   "Hello, Alice!" -> Option B

4. Quick Check:

   greet('Alice') = "Hello, Alice!" [OK]

Hint: Tool calls function directly with given input [OK]

Common Mistakes:

• Thinking the tool prints 'greet Alice'
• Assuming an error without agent context
• Ignoring the name parameter in output

4. Identify the error in this tool creation code:

def add_numbers(a, b):
    return a + b

from langchain.agents import Tool

add_tool = Tool(name='add', func=add_numbers, description='Adds two numbers')

result = add_tool.func(5)
print(result)

medium

A. Missing one argument when calling add_tool.func

B. Tool name must be uppercase

C. Description is too short

D. Function add_numbers should not return a value

Solution

1. Step 1: Check function parameters

   add_numbers requires two arguments: a and b.

2. Step 2: Check function call

   add_tool.func is called with only one argument (5), missing the second argument.

3. Final Answer:

   Missing one argument when calling add_tool.func -> Option A

4. Quick Check:

   Function needs 2 args, call has 1 = D [OK]

Hint: Match function parameters with call arguments count [OK]

Common Mistakes:

• Ignoring argument count mismatch
• Thinking tool name case matters
• Assuming description length causes error

5. You want to create a tool that converts temperatures from Celsius to Fahrenheit for an agent. Which code correctly creates this tool with a clear description?

hard

A. def convert_temp(f):
return (f - 32) * 5/9

from langchain.agents import Tool

tool = Tool(name='temp_convert', func=convert_temp, description='Converts Fahrenheit to Celsius')

B. def c_to_f(c):
return c + 32

from langchain.agents import Tool

temp_tool = Tool(name='temp', func=c_to_f, description='Temperature conversion')

C. def c_to_f(c):
return (c * 9/5) + 32

from langchain.agents import Tool

temp_tool = Tool(name='temp_convert', func=c_to_f, description='Converts Celsius to Fahrenheit')

D. def c_to_f(c):
return (c * 9/5) + 32

tool = Tool(func=c_to_f, description='Convert temp')

Solution

1. Step 1: Verify function correctness

   The c_to_f(c) function returns (c * 9/5) + 32, which correctly converts Celsius to Fahrenheit using the standard formula.

2. Step 2: Check tool creation parameters

   Tool(name='temp_convert', func=c_to_f, description='Converts Celsius to Fahrenheit') uses name, func, and a clear description matching the task.

3. Final Answer:

   def c_to_f(c):\n return (c * 9/5) + 32\n\nfrom langchain.agents import Tool\n\ntemp_tool = Tool(name='temp_convert', func=c_to_f, description='Converts Celsius to Fahrenheit') -> Option C

4. Quick Check:

   Correct formula and clear tool setup = A [OK]

Hint: Use correct formula and full tool parameters [OK]

Common Mistakes:

• Using wrong temperature formula
• Omitting tool name or description
• Confusing Celsius to Fahrenheit with reverse