Model parameters (temperature, max tokens) in LangChain - Mini Project: Build & Apply

Using Model Parameters in Langchain

📖 Scenario: You are building a simple chatbot using Langchain. You want to control how creative the chatbot's answers are and limit the length of its responses.

🎯 Goal: Learn how to set the temperature and max_tokens parameters in Langchain to control the chatbot's behavior.

📋 What You'll Learn

Create a Langchain OpenAI model instance with default settings

Add a variable for temperature to control creativity

Use max_tokens to limit response length

Update the model configuration to use these parameters

💡 Why This Matters

🌍 Real World

Controlling model parameters helps tailor AI responses for chatbots, content creation, or any application needing text generation.

💼 Career

Understanding how to configure AI model parameters is essential for AI developers, data scientists, and software engineers working with language models.

1

Create the Langchain OpenAI model instance

Write a line of code to create a Langchain OpenAI model instance called llm using OpenAI() with default settings.

LangChain

# Create the Langchain OpenAI model instance
# Your code here

Hint

Use llm = OpenAI() to create the model instance.

2

Add a temperature variable

Create a variable called temperature and set it to 0.7 to control the creativity of the model's responses.

LangChain

from langchain.llms import OpenAI

llm = OpenAI()
temperature = 0.7  # Set creativity level

Hint

Set temperature = 0.7 to make the model somewhat creative.

3

Add max_tokens variable

Create a variable called max_tokens and set it to 100 to limit the maximum length of the model's response.

LangChain

from langchain.llms import OpenAI

llm = OpenAI()
temperature = 0.7
max_tokens = 100  # Limit response length

Hint

Set max_tokens = 100 to limit the response length.

4

Configure the model with temperature and max_tokens

Update the llm instance to use the temperature and max_tokens variables by passing them as parameters to OpenAI().

LangChain

from langchain.llms import OpenAI

# Update llm to use temperature and max_tokens
llm = OpenAI(temperature=temperature, max_tokens=max_tokens)

Hint

Pass temperature=temperature and max_tokens=max_tokens when creating llm.

Practice

1. What does the temperature parameter control in a Langchain model?

easy

A. How creative or random the AI's answers are

B. The maximum length of the AI's response

C. The speed of the AI's response

D. The number of API calls allowed

Solution

1. Step 1: Understand the role of temperature

   The temperature parameter adjusts randomness in AI responses, making answers more or less creative.

2. Step 2: Differentiate from max tokens

   Max tokens limit response length, not creativity, so temperature controls creativity.

3. Final Answer:

   How creative or random the AI's answers are -> Option A

4. Quick Check:

   Temperature = creativity/randomness [OK]

Hint: Temperature controls creativity, not length or speed [OK]

Common Mistakes:

• Confusing temperature with max tokens
• Thinking temperature controls response length
• Assuming temperature affects API speed

2. Which of the following is the correct way to set max_tokens to 100 in a Langchain model call?

easy

A. model.call({temperature: 0.7, max_tokens: 100})

B. model.call({temperature: 0.7, maxTokens: 100})

C. model.call({temp: 0.7, max_tokens: 100})

D. model.call({temperature: 0.7, max_token: 100})

Solution

1. Step 1: Identify correct parameter names

   The Langchain model expects parameters named exactly as temperature and max_tokens.

2. Step 2: Check syntax correctness

   model.call({temperature: 0.7, max_tokens: 100}) uses correct parameter names and syntax; others have typos or wrong keys.

3. Final Answer:

   model.call({temperature: 0.7, max_tokens: 100}) -> Option A

4. Quick Check:

   Correct keys = temperature, max_tokens [OK]

Hint: Use exact parameter names: temperature and max_tokens [OK]

Common Mistakes:

• Using camelCase instead of snake_case
• Misspelling max_tokens as max_token
• Using temp instead of temperature

3. Given this code snippet:

response = model.call({"temperature": 0, "max_tokens": 5})
print(response)

What is the expected behavior of the AI's response?

medium

A. The AI gives a very creative and long answer

B. The AI gives a very random but short answer

C. The AI gives a deterministic and very short answer

D. The AI ignores parameters and gives a default answer

Solution

1. Step 1: Analyze temperature = 0

   Temperature 0 means no randomness, so the AI's answer is deterministic and predictable.

2. Step 2: Analyze max_tokens = 5

   Max tokens 5 limits the response length to very few words, making it short.

3. Final Answer:

   The AI gives a deterministic and very short answer -> Option C

4. Quick Check:

   Temperature 0 + max_tokens 5 = short, fixed answer [OK]

Hint: Temperature 0 = no randomness; max_tokens limits length [OK]

Common Mistakes:

• Thinking temperature 0 means creative output
• Ignoring max_tokens limit on length
• Assuming default behavior overrides parameters

4. You wrote this code:

response = model.call({"temperature": "high", "max_tokens": 50})

What is the main issue here?

medium

A. max_tokens should be a string, not a number

B. temperature parameter is missing

C. max_tokens value is too low

D. temperature value should be a number, not a string

Solution

1. Step 1: Check parameter types

   Temperature expects a number between 0 and 1 (or slightly above), not a string like "high".

2. Step 2: Validate max_tokens type

   Max_tokens is correctly a number (50), so no issue there.

3. Final Answer:

   temperature value should be a number, not a string -> Option D

4. Quick Check:

   Temperature must be numeric, not string [OK]

Hint: Temperature must be a number, not text [OK]

Common Mistakes:

• Passing string instead of number for temperature
• Assuming max_tokens can be string
• Ignoring type errors in parameters

5. You want the AI to generate a creative story but keep it short, about 50 words. Which parameter settings are best?

hard

A. temperature: 0.1, max_tokens: 10

B. temperature: 0.9, max_tokens: 50

C. temperature: 0, max_tokens: 200

D. temperature: 1.5, max_tokens: 5

Solution

1. Step 1: Choose temperature for creativity

   High temperature (close to 1) encourages creative, varied answers, so 0.9 fits well.

2. Step 2: Choose max_tokens for length

   Max tokens 50 limits response length to about 50 words, matching the short story requirement.

3. Step 3: Evaluate other options

   temperature: 0, max_tokens: 200 has no creativity; temperature: 0.1, max_tokens: 10 is too low creativity and very short; temperature: 1.5, max_tokens: 5 is too short and too high temperature causing randomness but too brief.

4. Final Answer:

   temperature: 0.9, max_tokens: 50 -> Option B

5. Quick Check:

   High creativity + short length = temperature: 0.9, max_tokens: 50 [OK]

Hint: High temperature + moderate max_tokens = creative but short [OK]

Common Mistakes:

• Using low temperature for creative tasks
• Setting max_tokens too low or too high
• Ignoring balance between creativity and length