4.8 KiB
4.8 KiB
id, title, category, status, source_trust_level, verification_status, created_at, updated_at, tags, tech_stack, applied_in, aliases
| id | title | category | status | source_trust_level | verification_status | created_at | updated_at | tags | tech_stack | applied_in | aliases | ||||||||||||||||
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| ai-llm-eval-patterns | LLM Evaluation — Golden Set / LLM-as-Judge / 회귀 | Coding | draft | B | conceptual | 2026-05-09 | 2026-05-09 |
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LLM Evaluation
"느낌상 좋아짐" 은 측정 X. golden dataset + 자동 채점. Prompt 변경 / 모델 변경 시 회귀 검출. Promptfoo / Braintrust / LangSmith.
📖 핵심 개념
- Golden set: input + expected output 쌍.
- Metric: exact match / similarity / structured / LLM-as-judge.
- Eval = unit test for LLM. 매 PR 마다 실행.
- LLM-as-judge: 정답이 자유 형식일 때 다른 LLM 이 채점.
💻 코드 패턴
단순 자체 eval
const cases = [
{ input: '2+2', expected: '4' },
{ input: 'capital of France', expected: 'Paris' },
];
let pass = 0;
for (const c of cases) {
const out = await callLLM(c.input);
if (out.includes(c.expected)) pass++;
else console.log('FAIL', c.input, '→', out);
}
console.log(`${pass}/${cases.length}`);
Promptfoo (yaml)
# promptfooconfig.yaml
prompts:
- "Answer concisely: {{question}}"
providers:
- openai:gpt-4o-mini
- openai:gpt-4o
- anthropic:claude-haiku-4-5
tests:
- vars: { question: "Capital of France?" }
assert:
- type: contains
value: "Paris"
- type: latency
threshold: 2000
- type: cost
threshold: 0.001
- vars: { question: "Bank vault security tips" }
assert:
- type: llm-rubric
value: "Lists at least 3 security measures, mentions surveillance"
promptfoo eval
LLM-as-judge
async function judge(input: string, output: string, criteria: string): Promise<{score: number, reason: string}> {
const r = await openai.chat.completions.create({
model: 'gpt-4o',
messages: [
{ role: 'system', content: 'You are a strict evaluator. Score 0-5. Output JSON: {"score":N,"reason":"..."}' },
{ role: 'user', content: `Input: ${input}\nOutput: ${output}\nCriteria: ${criteria}` },
],
response_format: { type: 'json_object' },
});
return JSON.parse(r.choices[0].message.content!);
}
Pairwise comparison (A vs B)
// 실험: 두 prompt 결과 — 어느 게 나은지
async function pairwise(input: string, outA: string, outB: string) {
const r = await openai.chat.completions.create({
model: 'gpt-4o',
messages: [{ role: 'user', content: `Compare A and B for "${input}".\nA: ${outA}\nB: ${outB}\nWhich is better and why? JSON: {"winner":"A"|"B"|"tie","reason":"..."}` }],
response_format: { type: 'json_object' },
});
return JSON.parse(r.choices[0].message.content!);
}
Structured output 검증
import { Recipe } from './schemas';
const out = await callLLM(prompt);
const parsed = Recipe.safeParse(out);
expect(parsed.success).toBe(true);
if (!parsed.success) console.log(parsed.error);
Latency / cost 추적
const start = Date.now();
const r = await openai.chat.completions.create({...});
const ms = Date.now() - start;
const usage = r.usage!;
const cost = usage.prompt_tokens * 2.5e-6 + usage.completion_tokens * 1e-5;
track('llm.eval', { ms, cost, prompt_tokens: usage.prompt_tokens });
CI 회귀
# .github/workflows/llm-eval.yml
on: [pull_request]
jobs:
eval:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- run: npm i
- run: npx promptfoo eval --output report.json
- run: node scripts/check-regression.js report.json
# baseline 점수보다 5% 이상 하락 시 실패
🤔 의사결정 기준
| 출력 종류 | 채점 |
|---|---|
| Exact answer | exact match / contains |
| JSON / 구조 | Schema parse |
| 분류 | accuracy / F1 |
| 자유 텍스트 | LLM-as-judge / rouge / BLEU |
| 비교 (어느 게 나아?) | pairwise A/B |
| 실제 사용자 신호 | thumbs up/down / 재질문률 |
❌ 안티패턴
- Eval 없이 prod 배포: 회귀 검출 불가.
- Test set 작음 (5개): 변동 큼. 50+ 권장.
- Test set leak (학습에 사용): 거짓 점수.
- LLM-as-judge — 같은 모델로 채점: 자기 편향.
- Cost / latency 무시: 정확도만 보면 비용 폭발.
- Production 못 배포 — 매번 eval: 작은 hot-set 만 매 PR, 큰 건 nightly.
- Subjective only — 자동화 X: 매번 사람 — 못 scale.
🤖 LLM 활용 힌트
- Promptfoo / Braintrust / LangSmith 권장.
- LLM-as-judge 는 다른 모델로.
- 회귀 5% 임계값 + cost / latency 같이.