typescriptbeginner

Few-Shot Prompt Template

Build structured few-shot prompts with examples, system instructions, and output format constraints.

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interface FewShotExample {
  input: string;
  output: string;
}

export function buildFewShotPrompt({
  systemPrompt,
  examples,
  userInput,
  outputFormat,
}: {
  systemPrompt: string;
  examples: FewShotExample[];
  userInput: string;
  outputFormat?: string;
}): { role: string; content: string }[] {
  const messages: { role: string; content: string }[] = [
    { role: 'system', content: systemPrompt },
  ];

  for (const ex of examples) {
    messages.push({ role: 'user', content: ex.input });
    messages.push({ role: 'assistant', content: ex.output });
  }

  const finalInput = outputFormat
    ? `${userInput}\n\nRespond in this format: ${outputFormat}`
    : userInput;

  messages.push({ role: 'user', content: finalInput });
  return messages;
}

// Usage:
// const messages = buildFewShotPrompt({
//   systemPrompt: 'Classify the sentiment',
//   examples: [
//     { input: 'Great product!', output: 'positive' },
//     { input: 'Terrible service', output: 'negative' },
//   ],
//   userInput: 'Works okay, nothing special',
// });