Today’s goal
Learn to recognize a RAG answer and ask what information it was based on.
Try a source-based answer
- 1
Copy the as written
The prompt already includes a short fictional passage. You do not need to provide anything of your own.
- 2
Read the summary and source references
The AI turns the passage into three points and identifies the sentence each one is based on.
- 3
Check each reference
Compare each point with the sentence it claims to be based on. Does that sentence appear in the passage as written?
- 4
Try the same approach with your own material
In this exercise, the full source passage is already included in the prompt. When you use a real document, open the original source yourself before relying on the answer to make a decision.
Copy and try it
Summarize these instructions in three points. After each point, identify the sentence it is based on: “Before a hike, I check the weather. I pack a water bottle. I send my route plan to a friend.”
Follow-up: ask about something the passage does not say
In the same conversation, ask: “What is the latest time I should return from the hike?” Check whether the AI says plainly that the passage does not say, or makes up an answer anyway.
The problem: AI does not know your information
AI knows general information, but it does not know your company’s product prices, your school’s rules or your notes. How can it still answer questions about your own material? The answer is RAG.
RAG = a visit to the extra fridge
RAG (short for Retrieval-Augmented Generation) is like checking an extra fridge before answering. AI is like a cook who knows how to cook in general. If you ask, “What do we have in the fridge?”, the cook does not answer from memory: they open the extra fridge and see what is actually there. RAG works the same way: AI first retrieves relevant passages from your material, then writes an answer based on them.
A vector database: a fridge organized by meaning
A vector database is like a fridge where everything is organized by meaning rather than alphabetically. When you ask a question, AI retrieves items whose meaning is similar to your question. That is why it can find “return policy” even if you use the word “refunds.”
RAG does not make a source automatically true
For example, if you ask what a return policy says, a good answer identifies the source passage. Still check that the information is correct and up to date. Also ask what material the service uses, when it was updated and whether you can see the sources yourself.
Why does this matter?
- AI can use supplied material as well as its general knowledge
- The material can be updated without retraining the model
- Customer service bots can answer about your return policies, opening hours and products
- The quality of the material, permission to use it and source visibility all affect how reliable an answer is
From answer to source trail
A common request:
Answer based on this document.
Try asking this instead:
Use only the document below. Answer the question, name the passage you used, identify missing information and say if the document is not enough to answer. Do not fill gaps with guesses.
RAG can help find a relevant passage, but the source and the answer still need to be distinguished.
Once you know the basics
Next, try the same thing with a different kind of AI: an open or small model that works without a large account or paid subscription. Checking the source matters just as much there as it does in this guide.
Free practice on this website
Recall how RAG works
Read the practice material once, cover it and answer in your own words. The hint and review criteria appear only after you submit an answer or choose “I don’t know yet.”
Your answers stay only in this browser tab. They are not sent to AI Licenses servers or analytics.
Question 1/3
Read the material before your first attempt
Once you have read the material, hide it using the button on the left and answer from memory.
Use the practice activity in your own AI service (optional)
The same question twice: from memory and from a source.
When AI is given source material, it answers differently than when it relies only on general knowledge. The difference is clearest when you ask it to do both in sequence.
Experiment · about 5 min
Where should we start?
How the prompt is structured
- Task
- Two answers and the difference between them
- Context
- The passage is fictional and provided
- Format
- A source reference for every claim
Answer the question below twice in the same conversation. First answer using only your general knowledge, even if you are unsure. Then answer using only the passage below, identify the sentence behind each claim, and finish with one sentence saying whether your first answer was correct, incorrect or incomplete according to the passage. Passage: “The community center is open on weekdays from 9 a.m. to 3 p.m. You can get the key from the caretaker. You can cancel a gym booking no later than the day before. Uncancelled bookings are charged.” Question: By when can a gym booking be cancelled?
Ready to try the experiment?
The experiment works with any assistant, and different services may behave differently. That is part of the lesson too.
Open ChatGPTThe passage is already in the prompt: The full practice passage is included in the prompt, so you do not need to attach anything of your own. When you try this with a real document, use only material you are authorized to use.
Skills and concepts in this guide
Publication details and sources
- Published:
- July 9, 2026
- Sources checked:
- September 4, 2026