Prompt Engineering - lesson 4 | HackIndia Skills

Prompt Engineering - lesson 4 | HackIndia Skills | HackIndia

Example

Prompt pattern

Here is a prompt for a student project that classifies hostel maintenance complaints. The app can show the category, urgency, and a short message to the warden.

You are helping a college hostel maintenance desk.

Task: Read the student's complaint and return JSON only.

Return this exact JSON shape:
{
  "category": "electricity | plumbing | cleaning | internet | furniture | other",
  "urgency": "low | medium | high",
  "summary": "string, max 20 words",
  "needsHumanReview": true
}

Rules:
- Use only one category.
- Set urgency to high only if safety, water leakage, no electricity, or blocked toilet is mentioned.
- If the complaint is unclear, use category "other" and set needsHumanReview to true.
- Return valid JSON only. No markdown. No extra text.

Complaint:
"Fan in room B-214 is sparking and smells burnt."

Example

Parse and validate

Even a good prompt is not enough. Your code must reject bad output and handle it safely.

This small JavaScript check is fine for a demo. For a larger app, use a validation library such as Zod.

const allowedCategories = ["electricity", "plumbing", "cleaning", "internet", "furniture", "other"];
const allowedUrgency = ["low", "medium", "high"];

function parseComplaintResult(modelText) {
  let data;
  try {
    data = JSON.parse(modelText);
  } catch {
    return { ok: false, error: "Model did not return valid JSON" };
  }

  if (!allowedCategories.includes(data.category)) return { ok: false, error: "Bad category" };
  if (!allowedUrgency.includes(data.urgency)) return { ok: false, error: "Bad urgency" };
  if (typeof data.summary !== "string" || data.summary.length > 140) return { ok: false, error: "Bad summary" };
  if (typeof data.needsHumanReview !== "boolean") return { ok: false, error: "Bad review flag" };

  return { ok: true, data };
}

Ask for Structured Output

The one rule

Why structure helps

Design the output

Prompt pattern

Parse and validate

Common mistake

Make failure visible

Do this now

Quick check