Mission: Grounded, 근거로만 답하는 사내 사서를 고용하라

import * as cdk from "aws-cdk-lib";
import { Construct } from "constructs";
import * as dynamodb from "aws-cdk-lib/aws-dynamodb";
import * as lambda from "aws-cdk-lib/aws-lambda";
import * as apigwv2 from "aws-cdk-lib/aws-apigatewayv2";
import * as integrations from "aws-cdk-lib/aws-apigatewayv2-integrations";
import * as s3 from "aws-cdk-lib/aws-s3";
import * as s3deploy from "aws-cdk-lib/aws-s3-deployment";
import * as cloudfront from "aws-cdk-lib/aws-cloudfront";
import * as origins from "aws-cdk-lib/aws-cloudfront-origins";
import * as iam from "aws-cdk-lib/aws-iam";

export class LibraryStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const answerModelId = this.node.tryGetContext("answerModelId") ?? "global.anthropic.claude-sonnet-4-6";
    const embedModelId = this.node.tryGetContext("embedModelId") ?? "amazon.titan-embed-text-v2:0";

    const table = new dynamodb.Table(this, "LibraryTable", {
      partitionKey: { name: "pk", type: dynamodb.AttributeType.STRING },
      sortKey: { name: "sk", type: dynamodb.AttributeType.STRING },
      billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
    });

    const ingestFn = new lambda.Function(this, "IngestFn", {
      runtime: lambda.Runtime.NODEJS_22_X,
      handler: "ingest.handler",
      code: lambda.Code.fromAsset("lambda"),
      environment: {
        TABLE_NAME: table.tableName,
        EMBED_MODEL_ID: embedModelId,
        // 발급 API 키 인증, 배포 셸에서 주입 (Bedrock IAM 정책 불필요)
        AWS_BEARER_TOKEN_BEDROCK: process.env.AWS_BEARER_TOKEN_BEDROCK ?? "",
      },
      timeout: cdk.Duration.seconds(29),
      memorySize: 512,
    });
    table.grantReadWriteData(ingestFn);

    const askFn = new lambda.Function(this, "AskFn", {
      runtime: lambda.Runtime.NODEJS_22_X,
      handler: "ask.handler",
      code: lambda.Code.fromAsset("lambda"),
      environment: {
        TABLE_NAME: table.tableName,
        EMBED_MODEL_ID: embedModelId,
        ANSWER_MODEL_ID: answerModelId,
        AWS_BEARER_TOKEN_BEDROCK: process.env.AWS_BEARER_TOKEN_BEDROCK ?? "",
      },
      timeout: cdk.Duration.seconds(29),
      memorySize: 512,
    });
    table.grantReadData(askFn);

    const api = new apigwv2.HttpApi(this, "LibraryApi", {
      corsPreflight: {
        allowOrigins: ["*"],
        allowMethods: [apigwv2.CorsHttpMethod.GET, apigwv2.CorsHttpMethod.POST, apigwv2.CorsHttpMethod.OPTIONS],
        allowHeaders: ["Content-Type"],
      },
    });
    const ingestInt = new integrations.HttpLambdaIntegration("IngestInt", ingestFn);
    const askInt = new integrations.HttpLambdaIntegration("AskInt", askFn);
    api.addRoutes({ path: "/ingest", methods: [apigwv2.HttpMethod.POST], integration: ingestInt });
    api.addRoutes({ path: "/docs", methods: [apigwv2.HttpMethod.GET], integration: ingestInt });
    api.addRoutes({ path: "/ask", methods: [apigwv2.HttpMethod.POST], integration: askInt });

    const siteBucket = new s3.Bucket(this, "SiteBucket", {
      blockPublicAccess: s3.BlockPublicAccess.BLOCK_ALL,
      removalPolicy: cdk.RemovalPolicy.DESTROY,
      autoDeleteObjects: true,
    });
    const dist = new cloudfront.Distribution(this, "SiteDist", {
      defaultBehavior: {
        origin: origins.S3BucketOrigin.withOriginAccessControl(siteBucket),
        viewerProtocolPolicy: cloudfront.ViewerProtocolPolicy.REDIRECT_TO_HTTPS,
      },
      defaultRootObject: "index.html",
    });
    new s3deploy.BucketDeployment(this, "DeploySite", {
      sources: [s3deploy.Source.asset("frontend")],
      destinationBucket: siteBucket,
      distribution: dist,
      distributionPaths: ["/*"],
    });

    new cdk.CfnOutput(this, "ApiUrl", { value: api.apiEndpoint });
    new cdk.CfnOutput(this, "SiteUrl", { value: `https://${dist.distributionDomainName}` });
    new cdk.CfnOutput(this, "TableName", { value: table.tableName });
  }
}

import * as cdk from "aws-cdk-lib";
import { LibraryStack } from "./library-stack";

const app = new cdk.App();
new LibraryStack(app, "LibraryStack", {
  env: { region: process.env.CDK_DEFAULT_REGION ?? "ap-northeast-2" },
  tags: { project: "capstone-librarian" },
});

// 청킹과 검색 랭킹. 임베딩 벡터는 밖에서 주입받는 순수 로직이다.
export function chunkText(text, max = 600) {
  const paras = String(text).split(/\n\s*\n/).map((s) => s.trim()).filter(Boolean);
  const chunks = [];
  let buf = "";
  for (const p of paras) {
    if (buf && (buf.length + p.length + 2) > max) {
      chunks.push(buf);
      buf = p;
    } else {
      buf = buf ? buf + "\n\n" + p : p;
    }
  }
  if (buf) chunks.push(buf);
  return chunks;
}

export function cosine(a, b) {
  let dot = 0, na = 0, nb = 0;
  for (let i = 0; i < a.length; i++) {
    dot += a[i] * b[i];
    na += a[i] * a[i];
    nb += b[i] * b[i];
  }
  return dot / (Math.sqrt(na) * Math.sqrt(nb) || 1);
}

export function rankChunks(chunks, qvec, k = 3) {
  return chunks
    .map((c) => ({ ...c, score: cosine(c.vector, qvec) }))
    .sort((x, y) => y.score - x.score)
    .slice(0, k);
}

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import { DynamoDBDocumentClient, PutCommand, QueryCommand } from "@aws-sdk/lib-dynamodb";
import { BedrockRuntimeClient, InvokeModelCommand } from "@aws-sdk/client-bedrock-runtime";
import { chunkText } from "./lib.mjs";

const ddb = DynamoDBDocumentClient.from(new DynamoDBClient({}));
const brt = new BedrockRuntimeClient({});
const TABLE = process.env.TABLE_NAME;
const EMBED_MODEL_ID = process.env.EMBED_MODEL_ID ?? "amazon.titan-embed-text-v2:0";
const CHUNK_MAX = Number(process.env.CHUNK_MAX ?? 240);
const CORS = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Headers": "Content-Type",
  "Access-Control-Allow-Methods": "GET,POST,OPTIONS",
};

export async function embed(text) {
  const res = await brt.send(new InvokeModelCommand({
    modelId: EMBED_MODEL_ID,
    contentType: "application/json",
    body: JSON.stringify({ inputText: String(text).slice(0, 8000), dimensions: 256, normalize: true }),
  }));
  return JSON.parse(new TextDecoder().decode(res.body)).embedding;
}

export const handler = async (event) => {
  const method = event.requestContext?.http?.method ?? "GET";
  const path = event.rawPath ?? "/";
  if (method === "OPTIONS") return { statusCode: 204, headers: CORS };

  try {
    if (path.endsWith("/docs")) {
      const res = await ddb.send(new QueryCommand({
        TableName: TABLE,
        KeyConditionExpression: "pk = :p",
        ExpressionAttributeValues: { ":p": "shelf" },
      }));
      return { statusCode: 200, headers: CORS, body: JSON.stringify({ docs: res.Items ?? [] }) };
    }

    const { title, text } = JSON.parse(event.body ?? "{}");
    if (!title || !text) {
      return { statusCode: 400, headers: CORS, body: JSON.stringify({ error: "title과 text 필요" }) };
    }
    const docId = `${Date.now()}-${Math.random().toString(36).slice(2, 6)}`;
    const chunks = chunkText(text, CHUNK_MAX);

    for (let i = 0; i < chunks.length; i++) {
      const vector = await embed(chunks[i]);
      await ddb.send(new PutCommand({
        TableName: TABLE,
        Item: {
          pk: "chunk", sk: `${docId}#${String(i).padStart(3, "0")}`,
          docId, title: String(title).slice(0, 60), text: chunks[i], vector,
        },
      }));
    }
    await ddb.send(new PutCommand({
      TableName: TABLE,
      Item: { pk: "shelf", sk: docId, title: String(title).slice(0, 60), chunks: chunks.length, at: new Date().toISOString() },
    }));
    return { statusCode: 201, headers: CORS, body: JSON.stringify({ doc_id: docId, title, chunks: chunks.length }) };
  } catch (err) {
    console.error("INGEST_ERROR", err.name, err.message);
    return { statusCode: 502, headers: CORS, body: JSON.stringify({ error: err.name, message: err.message }) };
  }
};

import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import { DynamoDBDocumentClient, QueryCommand } from "@aws-sdk/lib-dynamodb";
import { BedrockRuntimeClient, InvokeModelCommand, ConverseCommand } from "@aws-sdk/client-bedrock-runtime";
import { rankChunks } from "./lib.mjs";

const ddb = DynamoDBDocumentClient.from(new DynamoDBClient({}));
const brt = new BedrockRuntimeClient({});
const TABLE = process.env.TABLE_NAME;
const EMBED_MODEL_ID = process.env.EMBED_MODEL_ID ?? "amazon.titan-embed-text-v2:0";
const ANSWER_MODEL_ID = process.env.ANSWER_MODEL_ID ?? "global.anthropic.claude-sonnet-4-6";
const REFUSAL = "서가에 없는 내용입니다.";
const CORS = {
  "Access-Control-Allow-Origin": "*",
  "Access-Control-Allow-Headers": "Content-Type",
  "Access-Control-Allow-Methods": "GET,POST,OPTIONS",
};

async function embed(text) {
  const res = await brt.send(new InvokeModelCommand({
    modelId: EMBED_MODEL_ID,
    contentType: "application/json",
    body: JSON.stringify({ inputText: String(text).slice(0, 8000), dimensions: 256, normalize: true }),
  }));
  return JSON.parse(new TextDecoder().decode(res.body)).embedding;
}

export const handler = async (event) => {
  const method = event.requestContext?.http?.method ?? "POST";
  if (method === "OPTIONS") return { statusCode: 204, headers: CORS };

  try {
    const { question } = JSON.parse(event.body ?? "{}");
    if (!question) {
      return { statusCode: 400, headers: CORS, body: JSON.stringify({ error: "question 필요" }) };
    }

    const res = await ddb.send(new QueryCommand({
      TableName: TABLE,
      KeyConditionExpression: "pk = :p",
      ExpressionAttributeValues: { ":p": "chunk" },
    }));
    const all = res.Items ?? [];
    if (!all.length) {
      return { statusCode: 409, headers: CORS, body: JSON.stringify({ error: "서가가 비었습니다. shelve.sh를 먼저 실행하세요." }) };
    }

    const qvec = await embed(question);
    const top = rankChunks(all, qvec, 3);
    const context = top.map((c, i) => `[${i + 1}] (${c.title})\n${c.text}`).join("\n\n");

    const conv = await brt.send(new ConverseCommand({
      modelId: ANSWER_MODEL_ID,
      system: [{
        text: "당신은 사내 사서입니다. 아래 번호 자료에 있는 내용만 근거로 한국어로 간결히 답하고, " +
          `근거 문장 끝에 [번호]를 표기하세요. 자료에 근거가 없으면 정확히 "${REFUSAL}" 한 문장으로만 답하고 절대 추측하지 마세요.`,
      }],
      messages: [{ role: "user", content: [{ text: `질문: ${String(question).slice(0, 500)}\n\n자료:\n${context}` }] }],
      inferenceConfig: { maxTokens: 600 },
    }));
    const answer = conv.output?.message?.content?.find((c) => c.text)?.text ?? "";

    return {
      statusCode: 200, headers: CORS,
      body: JSON.stringify({
        answer,
        refused: answer.startsWith(REFUSAL),
        sources: top.map((c, i) => ({
          n: i + 1, title: c.title, score: Math.round(c.score * 1000) / 1000,
          preview: c.text.slice(0, 80),
        })),
      }),
    };
  } catch (err) {
    console.error("ASK_ERROR", err.name, err.message);
    return { statusCode: 502, headers: CORS, body: JSON.stringify({ error: err.name, message: err.message }) };
  }
};

<!DOCTYPE html>
<html lang="ko">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Claude Library</title>
<style>
  :root { --bg:#12181F; --card:#1B242E; --line:#2A3542; --text:#E8ECF1; --muted:#8B96A5; --accent:#FF9900; --green:#3FB950; --purple:#c9a2ff; }
  * { box-sizing:border-box; margin:0; }
  body { background:var(--bg); color:var(--text); font-family:system-ui,sans-serif; padding:28px 20px 60px; }
  .wrap { max-width:860px; margin:0 auto; }
  h1 { font-size:26px; } h1 em { color:var(--accent); font-style:normal; }
  .sub { color:var(--muted); font-size:13px; margin:4px 0 20px; }
  .panel { background:var(--card); border:1px solid var(--line); border-radius:12px; padding:18px; margin-bottom:16px; }
  .panel h2 { font-size:13px; color:var(--muted); letter-spacing:.06em; margin-bottom:12px; }
  ul#shelf { list-style:none; display:grid; gap:8px; }
  ul#shelf li { display:flex; justify-content:space-between; font-size:14px; padding:8px 10px; background:#0C1117; border-radius:8px; }
  ul#shelf .meta { color:var(--muted); font-size:12px; }
  input, textarea { width:100%; background:#0C1117; border:1px solid var(--line); border-radius:8px; color:var(--text); padding:10px 12px; font-size:14.5px; }
  textarea { min-height:90px; resize:vertical; margin-top:8px; }
  .row { display:flex; gap:10px; margin-top:10px; }
  .row input { flex:1; }
  button { background:var(--accent); border:0; border-radius:8px; color:#12181F; padding:10px 22px; font-weight:800; cursor:pointer; font-size:14.5px; white-space:nowrap; }
  button.ghost { background:transparent; color:var(--muted); border:1px solid var(--line); font-weight:600; }
  button:disabled { opacity:.5; }
  #answer { font-size:14.5px; line-height:1.75; white-space:pre-wrap; }
  #answer.refused { color:var(--purple); }
  .src { margin-top:12px; padding:10px 12px; background:#0C1117; border-radius:8px; font-size:12.5px; }
  .src .t { display:flex; justify-content:space-between; color:var(--muted); margin-bottom:4px; }
  .src .bar { height:5px; background:#2A3542; border-radius:3px; overflow:hidden; margin-top:6px; }
  .src .bar i { display:block; height:100%; background:var(--green); }
  .empty { color:var(--muted); font-size:13px; }
</style>
</head>
<body>
<div class="wrap">
  <h1><em>Claude</em> Library</h1>
  <div class="sub">근거 없이는 답하지 않는 사내 사서 - Capstone Lab D</div>

  <div class="panel">
    <h2>서가 <button class="ghost" id="reload" style="float:right;padding:4px 10px">새로고침</button></h2>
    <ul id="shelf"><li class="empty">서가 불러오는 중... (비어 있으면 shelve.sh를 실행하세요)</li></ul>
  </div>

  <div class="panel">
    <h2>문서 입고</h2>
    <input id="title" placeholder="문서 제목" maxlength="60">
    <textarea id="text" placeholder="본문을 붙여넣으세요. 빈 줄 기준으로 청킹되어 임베딩됩니다."></textarea>
    <div class="row"><span class="empty" id="ingest-msg"></span><button id="ingest">입고</button></div>
  </div>

  <div class="panel">
    <h2>사서에게 질문</h2>
    <div class="row">
      <input id="q" placeholder="예: 우리 회사 창립 연도는?">
      <button id="ask">질문</button>
    </div>
    <div style="margin-top:14px">
      <div id="answer" class="empty">아직 질문이 없습니다.</div>
      <div id="sources"></div>
    </div>
  </div>
</div>

<script>
"use strict";
var API_BASE = "PASTE_API_URL";

function loadShelf() {
  fetch(API_BASE + "/docs")
    .then(function (r) { return r.json(); })
    .then(function (d) {
      var ul = document.getElementById("shelf");
      if (!d.docs || !d.docs.length) { ul.innerHTML = '<li class="empty">서가가 비었습니다.</li>'; return; }
      ul.innerHTML = d.docs.map(function (x) {
        return "<li><span>" + x.title + '</span><span class="meta">' + x.chunks + " 청크</span></li>";
      }).join("");
    })
    .catch(function () {});
}
loadShelf();
document.getElementById("reload").addEventListener("click", loadShelf);

document.getElementById("ingest").addEventListener("click", function () {
  var title = document.getElementById("title").value.trim();
  var text = document.getElementById("text").value.trim();
  if (!title || !text) return;
  var btn = this, msg = document.getElementById("ingest-msg");
  btn.disabled = true; msg.textContent = "임베딩 중...";
  fetch(API_BASE + "/ingest", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ title: title, text: text })
  })
    .then(function (r) { return r.json(); })
    .then(function (d) {
      msg.textContent = d.chunks ? title + " 입고, " + d.chunks + " 청크" : (d.error || "실패");
      document.getElementById("title").value = ""; document.getElementById("text").value = "";
      loadShelf();
    })
    .catch(function (e) { msg.textContent = "오류: " + e.message; })
    .finally(function () { btn.disabled = false; });
});

document.getElementById("ask").addEventListener("click", function () {
  var q = document.getElementById("q").value.trim();
  if (!q) return;
  var btn = this, box = document.getElementById("answer"), src = document.getElementById("sources");
  btn.disabled = true;
  box.className = "empty"; box.textContent = "사서가 서가를 뒤지는 중...";
  src.innerHTML = "";
  fetch(API_BASE + "/ask", {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ question: q })
  })
    .then(function (r) { return r.json(); })
    .then(function (d) {
      if (!d.answer) { box.textContent = d.error || "실패"; return; }
      box.className = d.refused ? "refused" : "";
      box.textContent = d.answer;
      if (!d.refused && d.sources) {
        src.innerHTML = d.sources.map(function (s) {
          return '<div class="src"><div class="t"><span>[' + s.n + "] " + s.title +
                 "</span><span>유사도 " + s.score + '</span></div><div>' + s.preview +
                 '...</div><div class="bar"><i style="width:' + Math.round(s.score * 100) + '%"></i></div></div>';
        }).join("");
      }
    })
    .catch(function (e) { box.textContent = "오류: " + e.message; })
    .finally(function () { btn.disabled = false; });
});
</script>
</body>
</html>