Why Jinja Rules Prompt Engineering & Building Price Monitoring Agent - Full Tutorial
Colab Notebook: colab.research.google.com/drive/18nzaXc7__K..
Dynamic prompt generation has become a cornerstone of modern AI workflows.
Whether you're building personalized email campaigns, travel itineraries, or AI-driven recommendations, the ability to generate structured content dynamically is invaluable.
In this blog, we'll explore how Jinja2, a powerful templating engine, stands out in this domain and compare it with tools like LangChain for crafting dynamic prompts.
Why Dynamic Prompting Matters
If you are building an AI assistant tasked with creating personalized travel itineraries or summarizing user activities, static prompts won't cut it here – you need templates that adapt to the data at hand. This is where tools like Jinja2 and LangChain's prompt templates shine.
Jinja2: The All-Rounder for Dynamic Templates
Jinja2 is a versatile templating engine widely known for its use in web development but equally adept at generating dynamic text for emails, reports, and prompts. Here's why Jinja2 should be in your toolkit:
1. Seamless Integration of Logic
Jinja2 allows you to embed loops, conditionals, and filters directly in your templates. For example, creating tailored recommendations becomes straightforward:
Dear {{ user_name }},
Here’s a summary of your recent activities:
{% for activity in activities %}
- On {{ activity.date }}: {{ activity.description }}
{% endfor %}
{% if status == "pass" %}
Congratulations on passing the test. Keep up the great work!
{% else %}
Keep trying, and you'll get there!
{% endif %}
2. Readable and Reusable
With its clean syntax, Jinja2 makes templates easy to maintain and reuse across projects. It's perfect for use cases like:
Personalized emails
Travel itineraries
AI-driven content generation
3. Performance Efficiency
Jinja2 minimizes overhead, making it an excellent choice for applications requiring rapid dynamic rendering.
Comparing Jinja2 and LangChain for Prompt Templates
While Jinja2 excels in general-purpose dynamic content generation, LangChain's PromptTemplate is specifically designed for AI workflows, making it the go-to for LLM integrations.
LangChain Example:
from langchain.prompts import PromptTemplate
template = """
Dear {user_name},
Here’s a summary of your recent activities:
{activities}
Here are some tailored recommendations for you:
{recommendations}
{closing_note}
"""
prompt = PromptTemplate(
input_variables=["user_name", "activities", "recommendations", "closing_note"],
template=template,
)
email = prompt.format(
user_name="Alice",
activities="- Completed the Python course.\n- Joined the AI workshop.",
recommendations="- Read 'Deep Learning for Beginners'.\n- Join the Advanced AI Projects Club.",
closing_note="Congratulations on passing the test!",
)
print(email)
Key Differences:
Flexibility: Jinja2 supports complex logic directly in the template, while LangChain separates logic and content.
AI Integration: LangChain is optimized for workflows where prompts are fed into LLMs.
Learning Curve: Jinja2 has a gentler curve for general developers, whereas LangChain is ideal for those already in the AI ecosystem.
Real-World Use Case: Personalized Travel Itineraries
Using Jinja2, you can craft luxurious travel experiences tailored to user preferences. Here's an example:
Input Data
codeinput_data = {
"name": "John Doe",
"destination": "Paris, France",
"interests": ["art", "history", "fine dining"],
"travel_type": "luxury",
"suggested_activities": [
{"name": "Private Louvre Tour", "description": "Explore iconic art pieces with a guide."},
{"name": "Seine River Dinner Cruise", "description": "Enjoy a gourmet dinner on a Seine cruise."},
],
"recommended_accommodations": [
{"name": "Le Meurice", "description": "5-star luxury hotel with Michelin dining."},
],
}
Jinja2 Template
"""
Traveler Profile:
- Name: {{ name }}
- Age: {{ age }}
- Travel Dates: {{ travel_dates }}
- Travel Destination: {{ destination }}
- Interests: {{ interests|join(", ") }}
{% if travel_type == 'luxury' %}
The traveler prefers a luxury experience. Suggest the following premium activities and accommodations:
{% elif travel_type == 'adventure' %}
The traveler seeks adventure. Recommend these thrilling activities and adventurous destinations:
{% else %}
The traveler is interested in a balanced experience. Consider these activities and attractions:
{% endif %}
{% for activity in suggested_activities %}
- {{ activity.name }}: {{ activity.description }}
{% if activity.requirements %}
Requirements: {{ activity.requirements|join(", ") }}
{% endif %}
{% endfor %}
{% if recommended_accommodations %}
Recommended Accommodations:
{% for accommodation in recommended_accommodations %}
- {{ accommodation.name }}: {{ accommodation.description }}
Location: {{ accommodation.location }}
Amenities: {{ accommodation.amenities|join(", ") }}
{% endfor %}
{% endif %}
Traveler's Notes:
{% if traveler_notes %}
{% for note in traveler_notes %}
- {{ note }}
{% endfor %}
{% endif %}
Based on the above information, create a 3-day itinerary tailored to the traveler’s preferences and needs. Ensure activities, meals, and downtime are appropriately balanced.
""
Output
Traveler Profile:
- Name: John Doe
- Age: 35
- Travel Dates: 2024-01-15 to 2024-01-18
- Travel Destination: Paris, France
- Interests: art, history, fine dining, luxury shopping
The traveler prefers a luxury experience. Suggest the following premium activities and accommodations:
- Private Louvre Tour: Enjoy a private, guided tour of the Louvre Museum, exploring its iconic art pieces.
Requirements: Comfortable walking shoes, Museum pass
- Seine River Dinner Cruise: Experience a luxurious evening with a gourmet dinner on a Seine River cruise.
Requirements: Formal attire
- Champs-Élysées Shopping Tour: Indulge in a day of shopping at high-end boutiques along the Champs-Élysées.
Recommended Accommodations:
- Le Meurice: A 5-star luxury hotel offering Michelin-star dining and exceptional service.
Location: Rue de Rivoli, Paris
Amenities: Spa, Fine dining, Concierge service
- Hôtel Plaza Athénée: Iconic Parisian hotel with stunning views of the Eiffel Tower.
Location: Avenue Montaigne, Paris
Amenities: Luxury suites, Haute couture stores, Gourmet restaurants
Traveler's Notes:
- Has dietary restrictions: no shellfish.
- Prefers private tours over group activities.
Based on the above information, create a 3-day itinerary tailored to the traveler’s preferences and needs. Ensure activities, meals, and downtime are appropriately balanced.
Price Monitoring Agent | Part 2 | Full Tutorial
I published a full video tutorial on building a Price Monitoring Agent using Pydantic AI. I accomplished the below goal.
