What is prompt engineering and why does it matter?

Prompt engineering is the practice of designing and optimising text inputs (prompts) to get better outputs from AI language models.

**Why it matters:**
- Better prompts → more accurate, relevant responses
- Saves tokens → reduces API costs
- Enables complex reasoning with simple models

**Key techniques:**
1. **Zero-shot** — direct instruction without examples
2. **Few-shot** — provide 2-3 examples in the prompt
3. **Chain-of-thought** — ask the model to reason step-by-step
4. **Role prompting** — give the model a persona
5. **Output formatting** — specify JSON, markdown, etc.

Prompt engineering is one of the most valuable skills for AI product development.