4.2 — Few-Shot Prompting

CCAR-F Domain 4 · Task 4.2

What You Need to Know

Few-shot prompting puts a few worked examples (input + desired output + reasoning) in the prompt. It is the most effective technique for consistent, well-formatted output.

When to Deploy Few-Shot Examples

1. Detailed instructions alone produce inconsistent formatting
2. Model makes inconsistent judgement calls on ambiguous cases
3. Extraction returns empty/null fields for information the document contains

How to Construct Effective Examples

• Use 2 to 4 targeted examples
• Each example must show reasoning (why this action over alternatives)
• Cover the failing cases specifically

Key Concept: Few-shot examples are the most effective technique for consistency. Use 2–4 targeted examples with reasoning when instructions alone give inconsistent results, ambiguous judgements, or empty fields for data that exists.

Matching Technique to Problem

Problem	Correct Technique
Inconsistent output formatting	Few-shot examples
Malformed JSON	tool_use with JSON schemas
Fabricated values for missing fields	Optional/nullable schema fields
Wrong tool selection	Better tool descriptions first, then few-shot
Extraction sum ≠ total	Validation-retry loop

Exam Traps

• Choosing "add more detailed instructions" when formatting is inconsistent
• Adding many examples to cover every case
• Using confidence thresholds to fix inconsistent judgements