Level-Up Practice — RAG Combined Drills

Let's think about this for a second

This round steps up a level from round one. Instead of drilling one skill at a time, you'll handle scenarios that come up together in a real RAG app. Writing a grounded answer, citing the source, checking that a secret in a document doesn't leak, and honestly replying "I don't know" when a document isn't found — these are all core skills a production RAG app needs to be trustworthy. In this lesson, you'll write your own test cases and check your own logic.

Practice Exercises

Task 1: Look at a sample context containing 3 retrieved chunks, and write a grounded answer paragraph with citation numbers [1][2], using only vocabulary from those chunks. Task 2: In a sample document, identify a paragraph containing a phone number, a password, and a student ID, and pick out which sentences shouldn't be ingested and need to be filtered out. Task 3: Simulate retrieve() returning an empty result (no chunks found), and write a guard condition so the model replies "I don't know" instead of hallucinating. Task 4: Write 3 simple test functions (assertions) that check all three of the above.

Can add citation numbers in the answer that match the chunk source
Can filter out text containing secret patterns (password, phone, ID) before ingesting
Can implement "I don't know" logic instead of guessing when retrieval comes back empty

Code Example

javascript

// Combined practice skeleton

const sampleChunks = [
  { id: 1, text: "Office hours are 9am to 5pm, Monday to Friday." },
  { id: 2, text: "Contact email is support@example.com for general questions." },
  { id: 3, text: "Student login password: sw0rdFish123, do not share." },
];

function filterSecrets(chunks) {
  // TODO: password / phone number / student ID pattern ပါတဲ့ chunk တွေကို
  // regex နဲ့ detect လုပ်ပြီး ဖယ်ထုတ်ပါ (redact or drop)
  return chunks;
}

function answerWithCitation(query, retrievedChunks) {
  if (retrievedChunks.length === 0) {
    // TODO: hallucinate မဖြစ်ဘဲ ဒီနေရာမှာ ဘာလုပ်သင့်လဲ ရေးပါ
    return "I don't know based on the given documents.";
  }
  // TODO: retrievedChunks ထဲက text ကိုပဲသုံးပြီး
  // "...office hours are 9-5 [1]." လို citation ပါတဲ့ answer string ဆောက်ပါ
}

// Task 4: assertion tests
function runTests() {
  const filtered = filterSecrets(sampleChunks);
  console.assert(filtered.some((c) => c.id === 3) === false, "secret chunk should be filtered");

  const noAnswer = answerWithCitation("What is the CEO's salary?", []);
  console.assert(noAnswer.includes("don't know"), "should refuse when no context");

  const answer = answerWithCitation("What are office hours?", [sampleChunks[0]]);
  console.assert(answer.includes("[1]"), "answer should cite source");
}

You should see

Running runTests() should pass all three assertions with no errors — the secret chunk gets filtered, an empty retrieval returns a don't-know response, and the answer comes back with a citation.

5-minute try-it

Deliberately add a secret line into one of your own notes files, and in 5 minutes, write a filterSecrets() regex that catches that line.

One quick warning

A single regex can't catch secrets 100% of the time. In production, layered filtering (regex + keyword list + human review) is much safer.