Zero-Shot vs Few-Shot Prompting
What you'll learn
- Define zero-shot and few-shot prompting
- Know when examples are worth the extra tokens
- Write a few-shot prompt that locks in a format
Two dials, one idea
Zero-shot prompting gives the model an instruction and nothing else: “Classify this message as billing, bug, or feature request.” Modern models are good enough that zero-shot handles a huge range of everyday tasks.
Few-shot prompting adds a few worked examples before the real input:
"I was charged twice" -> BILLING
"Export button does nothing" -> BUG
"Please add dark mode" -> FEATURE_REQUEST
"My invoice shows the wrong amount" ->
The model reads the pattern and continues it. This is in-context learning — the model isn’t retrained, it just imitates the demonstrated behaviour for this request.
When to spend the extra tokens
Examples cost tokens, so use them where they earn their keep:
- You need an exact format. A couple of examples lock the output shape far more reliably than describing it.
- The task is nuanced or ambiguous. Edge cases the model would otherwise guess at get pinned down by showing how you want them handled.
- You’re seeing drift. If a zero-shot prompt gives inconsistent results, two or three examples usually stabilise it.
For simple, common tasks, skip the examples — they add cost without adding quality.
The golden rule of examples
The model imitates your examples exactly, flaws and all. So they must be:
- Consistent — same format, same labelling logic throughout.
- Representative — include a hard or edge case, not just easy ones, or the model won’t generalise.
- Correct — a wrong example teaches wrong behaviour.
Get those right and few-shot is the highest-leverage move in prompting. Next: system prompts and roles, which set behaviour for an entire conversation instead of a single message.
Classify each support message as: BILLING, BUG, or FEATURE_REQUEST. Examples: "I was charged twice this month" -> BILLING "The export button does nothing" -> BUG "Please add dark mode" -> FEATURE_REQUEST Now classify: "My invoice shows the wrong amount" ->
BILLING
Sample output — AI responses may vary.
Common mistakes
- Adding examples that are inconsistent with each other — the model copies the inconsistency. Your examples must model exactly the behaviour you want.
- Using few-shot for everything. For simple, well-known tasks, examples just waste tokens without improving results.
- Picking unrepresentative examples. If your examples are all easy cases, the model won't learn the hard ones.
How to check the AI's answer
- Test the prompt on tricky, edge-case inputs — not just the ones similar to your examples — to see if the pattern really generalised.
- If output format drifts, add one more example that demonstrates the exact format; consistency usually snaps back.
Key terms
Test yourself
3 questions · answers reveal after you check.
1. Zero-shot prompting means…
Zero-shot = a direct instruction with no worked examples. Few-shot adds examples.
2. When is few-shot most worth the extra tokens?
Examples pay off when you need a precise output shape or the task has subtle rules the model won't guess.
3. Your few-shot examples contradict each other on format. What happens?
Examples are powerful precisely because the model imitates them — so inconsistent examples produce inconsistent output.