fix(upload): 100MB 초과 파일 사전 차단 + NAS file_watcher 안내

home-caddy 의 request_body max_size 100MB 한도 (infra_inventory.md D8 /
Cloudflare 섹션 참조) 에 걸리는 업로드 시 사용자 콘솔에 의미 없는 413 만
나오던 문제. 이제:

1. 클라이언트 사전 검사: 100MB 초과 파일은 업로드 자체를 시도 안 하고
   즉시 toast 로 안내 (파일명 + 크기 + NAS 우회 경로)
2. 서버 fallback: 사전 검사를 통과했으나 인프라 한도에 걸려 413 응답이
   오는 경우에도 같은 안내 메시지

NAS 우회 경로: NAS 의 PKM 폴더에 직접 두면 file_watcher 가 5분 간격으로
자동 인덱싱. 이게 100MB+ 파일의 정식 처리 경로 (infra_inventory.md
Cloudflare 섹션의 413 정책).

CLAUDE.md

@@ -1,5 +1,20 @@
 # hyungi_Document_Server — Claude Code 작업 가이드
 
+## Infrastructure Reference 📌
+
+**Always refer to** `~/.claude/projects/-Users-hyungiahn/memory/infra_inventory.md` for:
+- AI model routing (primary / fallback / embedding / rerank / vision) — **the model names below may be stale**
+- Machine info, Tailscale IPs, SSH targets
+- Docker container topology and compose projects
+- Drift log (known Desired vs Actual inconsistencies)
+- Verify commands
+
+**If this file and `infra_inventory.md` disagree, `infra_inventory.md` is authoritative.** Do not change `config.yaml` / `credentials.env` without first updating `infra_inventory.md`.
+
+**Search experiment soft lock**: During Phase 2 work (search.py refactor, QueryAnalyzer, run_eval.py execution), do **not** run `docker compose restart`, change `config.yaml`, or pull Ollama models. Violating this invalidates the experiment baseline.
+
+---
+
 ## 프로젝트 개요
 
 Self-hosted PKM(Personal Knowledge Management) 웹 애플리케이션.

app/api/digest.py

@@ -0,0 +1,164 @@
+"""Phase 4 Global Digest API — read-only + 디버그 regenerate.
+
+엔드포인트:
+- GET  /api/digest/latest                 : 가장 최근 digest
+- GET  /api/digest?date=YYYY-MM-DD         : 특정 날짜 digest
+- GET  /api/digest?country=KR              : 특정 국가만
+- POST /api/digest/regenerate              : 백그라운드 digest 워커 트리거 (auth 필요)
+
+응답은 country → topic 2-level 구조. country 가 비어있는 경우 응답에서 자동 생략.
+"""
+
+import asyncio
+from datetime import date as date_type
+from datetime import datetime
+from typing import Annotated
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+from pydantic import BaseModel
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import selectinload
+
+from core.auth import get_current_user
+from core.database import get_session
+from models.digest import DigestTopic, GlobalDigest
+from models.user import User
+
+router = APIRouter()
+
+
+# ─── Pydantic 응답 모델 (schemas/ 디렉토리 미사용 → inline 정의) ───
+
+
+class TopicResponse(BaseModel):
+    topic_rank: int
+    topic_label: str
+    summary: str
+    article_ids: list[int]
+    article_count: int
+    importance_score: float
+    raw_weight_sum: float
+    llm_fallback_used: bool
+
+
+class CountryGroup(BaseModel):
+    country: str
+    topics: list[TopicResponse]
+
+
+class DigestResponse(BaseModel):
+    digest_date: date_type
+    window_start: datetime
+    window_end: datetime
+    decay_lambda: float
+    total_articles: int
+    total_countries: int
+    total_topics: int
+    generation_ms: int | None
+    llm_calls: int
+    llm_failures: int
+    status: str
+    countries: list[CountryGroup]
+
+
+# ─── helpers ───
+
+
+def _build_response(digest: GlobalDigest, country_filter: str | None = None) -> DigestResponse:
+    """ORM 객체 → DigestResponse. country_filter 가 주어지면 해당 국가만."""
+    topics_by_country: dict[str, list[TopicResponse]] = {}
+    for t in sorted(digest.topics, key=lambda x: (x.country, x.topic_rank)):
+        if country_filter and t.country != country_filter:
+            continue
+        topics_by_country.setdefault(t.country, []).append(
+            TopicResponse(
+                topic_rank=t.topic_rank,
+                topic_label=t.topic_label,
+                summary=t.summary,
+                article_ids=list(t.article_ids or []),
+                article_count=t.article_count,
+                importance_score=t.importance_score,
+                raw_weight_sum=t.raw_weight_sum,
+                llm_fallback_used=t.llm_fallback_used,
+            )
+        )
+
+    countries = [
+        CountryGroup(country=c, topics=topics_by_country[c])
+        for c in sorted(topics_by_country.keys())
+    ]
+
+    return DigestResponse(
+        digest_date=digest.digest_date,
+        window_start=digest.window_start,
+        window_end=digest.window_end,
+        decay_lambda=digest.decay_lambda,
+        total_articles=digest.total_articles,
+        total_countries=digest.total_countries,
+        total_topics=digest.total_topics,
+        generation_ms=digest.generation_ms,
+        llm_calls=digest.llm_calls,
+        llm_failures=digest.llm_failures,
+        status=digest.status,
+        countries=countries,
+    )
+
+
+async def _load_digest(
+    session: AsyncSession,
+    target_date: date_type | None,
+) -> GlobalDigest | None:
+    """date 가 주어지면 해당 날짜, 아니면 최신 digest 1건."""
+    query = select(GlobalDigest).options(selectinload(GlobalDigest.topics))
+    if target_date is not None:
+        query = query.where(GlobalDigest.digest_date == target_date)
+    else:
+        query = query.order_by(GlobalDigest.digest_date.desc())
+    query = query.limit(1)
+    result = await session.execute(query)
+    return result.scalar_one_or_none()
+
+
+# ─── Routes ───
+
+
+@router.get("/latest", response_model=DigestResponse)
+async def get_latest(
+    user: Annotated[User, Depends(get_current_user)],
+    session: Annotated[AsyncSession, Depends(get_session)],
+):
+    """가장 최근 생성된 global digest."""
+    digest = await _load_digest(session, target_date=None)
+    if digest is None:
+        raise HTTPException(status_code=404, detail="아직 생성된 digest 없음")
+    return _build_response(digest)
+
+
+@router.get("", response_model=DigestResponse)
+async def get_digest(
+    user: Annotated[User, Depends(get_current_user)],
+    session: Annotated[AsyncSession, Depends(get_session)],
+    date: date_type | None = Query(default=None, description="YYYY-MM-DD (KST)"),
+    country: str | None = Query(default=None, description="국가 코드 (예: KR)"),
+):
+    """특정 날짜 또는 국가 필터링된 digest. date 미지정 시 최신."""
+    digest = await _load_digest(session, target_date=date)
+    if digest is None:
+        raise HTTPException(
+            status_code=404,
+            detail=f"digest 없음 (date={date})" if date else "아직 생성된 digest 없음",
+        )
+    country_filter = country.upper() if country else None
+    return _build_response(digest, country_filter=country_filter)
+
+
+@router.post("/regenerate")
+async def regenerate(
+    user: Annotated[User, Depends(get_current_user)],
+):
+    """디버그용 수동 트리거 — 백그라운드 태스크로 워커 실행 (auth 필요)."""
+    from workers.digest_worker import run
+
+    asyncio.create_task(run())
+    return {"status": "started", "message": "global_digest 워커 백그라운드 실행 시작"}

app/api/documents.py

@@ -142,11 +142,12 @@ async def list_documents(
     user: Annotated[User, Depends(get_current_user)],
     session: Annotated[AsyncSession, Depends(get_session)],
     page: int = Query(1, ge=1),
-    page_size: int = Query(20, ge=1, le=100),
+    page_size: int = Query(20, ge=1, le=500),
     domain: str | None = None,
     sub_group: str | None = None,
     source: str | None = None,
     format: str | None = None,
+    review_status: str | None = Query(None, description="pending | approved | rejected"),
 ):
     """문서 목록 조회 (페이지네이션 + 필터, 뉴스 제외)"""
     query = select(Document).where(Document.deleted_at == None, Document.source_channel != "news")
@@ -158,6 +159,8 @@ async def list_documents(
         query = query.where(Document.source_channel == source)
     if format:
         query = query.where(Document.file_format == format)
+    if review_status:
+        query = query.where(Document.review_status == review_status)
 
     # 전체 건수
     count_query = select(func.count()).select_from(query.subquery())

app/api/search.py

@@ -1,11 +1,16 @@
-"""하이브리드 검색 API — orchestrator (Phase 1.1: thin endpoint).
+"""하이브리드 검색 API — thin endpoint (Phase 3.1 이후).
 
-retrieval / fusion / rerank 등 실제 로직은 services/search/* 모듈로 분리.
-이 파일은 mode 분기, 응답 직렬화, debug 응답 구성, BackgroundTask dispatch만 담당.
+실제 검색 파이프라인(retrieval → fusion → rerank → diversity → confidence)
+은 `services/search/search_pipeline.py::run_search()` 로 분리되어 있다.
+이 파일은 다음만 담당:
+  - Pydantic 스키마 (SearchResult / SearchResponse / SearchDebug / DebugCandidate
+    / Citation / AskResponse / AskDebug)
+  - `/search` endpoint wrapper (run_search 호출 + logger + telemetry + 직렬화)
+  - `/ask` endpoint wrapper (Phase 3.3 에서 추가)
 """
 
 import time
-from typing import Annotated
+from typing import Annotated, Literal
 
 from fastapi import APIRouter, BackgroundTasks, Depends, Query
 from pydantic import BaseModel
@@ -15,20 +20,11 @@ from core.auth import get_current_user
 from core.database import get_session
 from core.utils import setup_logger
 from models.user import User
-from services.search.fusion_service import DEFAULT_FUSION, get_strategy, normalize_display_scores
-from services.search.rerank_service import (
-    MAX_CHUNKS_PER_DOC,
-    MAX_RERANK_INPUT,
-    apply_diversity,
-    rerank_chunks,
-)
-from services.search.retrieval_service import compress_chunks_to_docs, search_text, search_vector
-from services.search_telemetry import (
-    compute_confidence,
-    compute_confidence_hybrid,
-    compute_confidence_reranked,
-    record_search_event,
-)
+from services.search.evidence_service import EvidenceItem, extract_evidence
+from services.search.fusion_service import DEFAULT_FUSION
+from services.search.search_pipeline import PipelineResult, run_search
+from services.search.synthesis_service import SynthesisResult, synthesize
+from services.search_telemetry import record_search_event
 
 # logs/search.log + stdout 동시 출력 (Phase 0.4)
 logger = setup_logger("search")
@@ -56,6 +52,10 @@ class SearchResult(BaseModel):
     chunk_id: int | None = None
     chunk_index: int | None = None
     section_title: str | None = None
+    # Phase 3.1: reranker raw score 보존 (display score drift 방지).
+    # rerank 경로를 탄 chunk에만 채워짐. normalize_display_scores는 이 필드를
+    # 건드리지 않는다. Phase 3 evidence fast-path 판단에 사용.
+    rerank_score: float | None = None
 
 
 # ─── Phase 0.4: 디버그 응답 스키마 ─────────────────────────
@@ -98,6 +98,29 @@ def _to_debug_candidates(rows: list[SearchResult], n: int = 20) -> list[DebugCan
     ]
 
 
+def _build_search_debug(pr: PipelineResult) -> SearchDebug:
+    """PipelineResult → SearchDebug (기존 search()의 debug 구성 블록 복사)."""
+    return SearchDebug(
+        timing_ms=pr.timing_ms,
+        text_candidates=(
+            _to_debug_candidates(pr.text_results)
+            if pr.text_results or pr.mode != "vector"
+            else None
+        ),
+        vector_candidates=(
+            _to_debug_candidates(pr.vector_results)
+            if pr.vector_results or pr.mode in ("vector", "hybrid")
+            else None
+        ),
+        fused_candidates=(
+            _to_debug_candidates(pr.results) if pr.mode == "hybrid" else None
+        ),
+        confidence=pr.confidence_signal,
+        notes=pr.notes,
+        query_analysis=pr.query_analysis,
+    )
+
+
 @router.get("/", response_model=SearchResponse)
 async def search(
     q: str,
@@ -115,134 +138,301 @@ async def search(
         True,
         description="bge-reranker-v2-m3 활성화 (Phase 1.3, hybrid 모드만 동작)",
     ),
+    analyze: bool = Query(
+        False,
+        description="QueryAnalyzer 활성화 (Phase 2.1, LLM 호출). Phase 2.1은 debug 노출만, 검색 경로 영향 X",
+    ),
     debug: bool = Query(False, description="단계별 candidates + timing 응답에 포함"),
 ):
-    """문서 검색 — FTS + ILIKE + 벡터 결합 (Phase 0.5: RRF fusion)"""
-    timing: dict[str, float] = {}
-    notes: list[str] = []
-    text_results: list[SearchResult] = []
-    vector_results: list[SearchResult] = []  # doc-level (압축 후, fusion 입력)
-    raw_chunks: list[SearchResult] = []  # chunk-level (raw, Phase 1.3 reranker용)
-    chunks_by_doc: dict[int, list[SearchResult]] = {}  # Phase 1.3 reranker용 보존
-
-    t_total = time.perf_counter()
-
-    if mode == "vector":
-        t0 = time.perf_counter()
-        raw_chunks = await search_vector(session, q, limit)
-        timing["vector_ms"] = (time.perf_counter() - t0) * 1000
-        if not raw_chunks:
-            notes.append("vector_search_returned_empty (AI client error or no embeddings)")
-        # vector 단독 모드도 doc 압축해서 다양성 확보 (chunk 중복 방지)
-        vector_results, chunks_by_doc = compress_chunks_to_docs(raw_chunks, limit)
-        results = vector_results
-    else:
-        t0 = time.perf_counter()
-        text_results = await search_text(session, q, limit)
-        timing["text_ms"] = (time.perf_counter() - t0) * 1000
-
-        if mode == "hybrid":
-            t1 = time.perf_counter()
-            raw_chunks = await search_vector(session, q, limit)
-            timing["vector_ms"] = (time.perf_counter() - t1) * 1000
-
-            # chunk-level → doc-level 압축 (raw chunks는 chunks_by_doc에 보존)
-            t1b = time.perf_counter()
-            vector_results, chunks_by_doc = compress_chunks_to_docs(raw_chunks, limit)
-            timing["compress_ms"] = (time.perf_counter() - t1b) * 1000
-
-            if not vector_results:
-                notes.append("vector_search_returned_empty — text-only fallback")
-
-            t2 = time.perf_counter()
-            strategy = get_strategy(fusion)
-            # fusion은 doc 기준 — 더 넓게 가져옴 (rerank 후보용)
-            fusion_limit = max(limit * 5, 100) if rerank else limit
-            fused_docs = strategy.fuse(text_results, vector_results, q, fusion_limit)
-            timing["fusion_ms"] = (time.perf_counter() - t2) * 1000
-            notes.append(f"fusion={strategy.name}")
-            notes.append(
-                f"chunks raw={len(raw_chunks)} compressed={len(vector_results)} "
-                f"unique_docs={len(chunks_by_doc)}"
+    """문서 검색 — FTS + ILIKE + 벡터 결합 (Phase 3.1 이후 run_search wrapper)"""
+    pr = await run_search(
+        session,
+        q,
+        mode=mode,  # type: ignore[arg-type]
+        limit=limit,
+        fusion=fusion,
+        rerank=rerank,
+        analyze=analyze,
     )
 
-            if rerank:
-                # Phase 1.3: reranker — chunk 기준 입력
-                # fusion 결과 doc_id로 chunks_by_doc에서 raw chunks 회수
-                t3 = time.perf_counter()
-                rerank_input: list[SearchResult] = []
-                for doc in fused_docs:
-                    chunks = chunks_by_doc.get(doc.id, [])
-                    if chunks:
-                        # doc당 max 2 chunk (latency/VRAM 보호)
-                        rerank_input.extend(chunks[:MAX_CHUNKS_PER_DOC])
-                    else:
-                        # text-only 매치 doc → doc 자체를 chunk처럼 wrap
-                        rerank_input.append(doc)
-                    if len(rerank_input) >= MAX_RERANK_INPUT:
-                        break
-                rerank_input = rerank_input[:MAX_RERANK_INPUT]
-                notes.append(f"rerank input={len(rerank_input)}")
-
-                reranked = await rerank_chunks(q, rerank_input, limit * 3)
-                timing["rerank_ms"] = (time.perf_counter() - t3) * 1000
-
-                # diversity (chunk → doc 압축, max_per_doc=2, top score>0.90 unlimited)
-                t4 = time.perf_counter()
-                results = apply_diversity(reranked, max_per_doc=MAX_CHUNKS_PER_DOC)[:limit]
-                timing["diversity_ms"] = (time.perf_counter() - t4) * 1000
-            else:
-                # rerank 비활성: fused_docs를 그대로 (limit 적용)
-                results = fused_docs[:limit]
-        else:
-            results = text_results
-
-    # display score 정규화 — 프론트엔드는 score*100을 % 표시.
-    # fusion 내부 score(RRF는 0.01~0.05 범위)를 그대로 노출하면 표시가 깨짐.
-    normalize_display_scores(results)
-
-    timing["total_ms"] = (time.perf_counter() - t_total) * 1000
-
-    # confidence는 fusion 적용 전 raw 신호로 계산 (Phase 0.5 이후 fused score는 절대값 의미 없음)
-    # rerank 활성 시 reranker score가 가장 신뢰할 수 있는 신호 → 우선 사용
-    if mode == "hybrid":
-        if rerank and "rerank_ms" in timing:
-            confidence_signal = compute_confidence_reranked(results)
-        else:
-            confidence_signal = compute_confidence_hybrid(text_results, vector_results)
-    elif mode == "vector":
-        confidence_signal = compute_confidence(vector_results, "vector")
-    else:
-        confidence_signal = compute_confidence(text_results, mode)
-
     # 사용자 feedback: 모든 단계 timing은 debug 응답과 별도로 항상 로그로 남긴다
-    timing_str = " ".join(f"{k}={v:.0f}" for k, v in timing.items())
+    timing_str = " ".join(f"{k}={v:.0f}" for k, v in pr.timing_ms.items())
     fusion_str = f" fusion={fusion}" if mode == "hybrid" else ""
+    analyzer_str = (
+        f" analyzer=hit={pr.analyzer_cache_hit}/conf={pr.analyzer_confidence:.2f}/tier={pr.analyzer_tier}"
+        if analyze
+        else ""
+    )
     logger.info(
-        "search query=%r mode=%s%s results=%d conf=%.2f %s",
-        q[:80], mode, fusion_str, len(results), confidence_signal, timing_str,
+        "search query=%r mode=%s%s%s results=%d conf=%.2f %s",
+        q[:80],
+        pr.mode,
+        fusion_str,
+        analyzer_str,
+        len(pr.results),
+        pr.confidence_signal,
+        timing_str,
     )
 
     # Phase 0.3: 실패 자동 로깅 (응답 latency에 영향 X — background task)
+    # Phase 2.1: analyze=true일 때만 analyzer_confidence 전달 (False는 None → 기존 호환)
     background_tasks.add_task(
-        record_search_event, q, user.id, results, mode, confidence_signal
+        record_search_event,
+        q,
+        user.id,
+        pr.results,
+        pr.mode,
+        pr.confidence_signal,
+        pr.analyzer_confidence if analyze else None,
     )
 
-    debug_obj: SearchDebug | None = None
-    if debug:
-        debug_obj = SearchDebug(
-            timing_ms=timing,
-            text_candidates=_to_debug_candidates(text_results) if text_results or mode != "vector" else None,
-            vector_candidates=_to_debug_candidates(vector_results) if vector_results or mode in ("vector", "hybrid") else None,
-            fused_candidates=_to_debug_candidates(results) if mode == "hybrid" else None,
-            confidence=confidence_signal,
-            notes=notes,
-        )
+    debug_obj = _build_search_debug(pr) if debug else None
 
     return SearchResponse(
-        results=results,
-        total=len(results),
+        results=pr.results,
+        total=len(pr.results),
         query=q,
-        mode=mode,
+        mode=pr.mode,
+        debug=debug_obj,
+    )
+
+
+# ═══════════════════════════════════════════════════════════
+# Phase 3.3: /api/search/ask — Evidence + Grounded Synthesis
+# ═══════════════════════════════════════════════════════════
+
+
+class Citation(BaseModel):
+    """answer 본문의 [n] 에 해당하는 근거 단일 행."""
+
+    n: int
+    chunk_id: int | None
+    doc_id: int
+    title: str | None
+    section_title: str | None
+    span_text: str  # evidence LLM 이 추출한 50~300자
+    full_snippet: str  # 원본 800자 (citation 원문 보기 전용)
+    relevance: float
+    rerank_score: float
+
+
+class AskDebug(BaseModel):
+    """`/ask?debug=true` 응답 확장."""
+
+    timing_ms: dict[str, float]
+    search_notes: list[str]
+    query_analysis: dict | None = None
+    confidence_signal: float
+    evidence_candidate_count: int
+    evidence_kept_count: int
+    evidence_skip_reason: str | None
+    synthesis_cache_hit: bool
+    synthesis_prompt_preview: str | None = None
+    synthesis_raw_preview: str | None = None
+    hallucination_flags: list[str] = []
+
+
+class AskResponse(BaseModel):
+    """`/ask` 응답. `/search` 의 SearchResult 는 그대로 재사용."""
+
+    results: list[SearchResult]
+    ai_answer: str | None
+    citations: list[Citation]
+    synthesis_status: Literal[
+        "completed", "timeout", "skipped", "no_evidence", "parse_failed", "llm_error"
+    ]
+    synthesis_ms: float
+    confidence: Literal["high", "medium", "low"] | None
+    refused: bool
+    no_results_reason: str | None
+    query: str
+    total: int
+    debug: AskDebug | None = None
+
+
+def _map_no_results_reason(
+    pr: PipelineResult,
+    evidence: list[EvidenceItem],
+    ev_skip: str | None,
+    sr: SynthesisResult,
+) -> str | None:
+    """사용자에게 보여줄 한국어 메시지 매핑.
+
+    Failure mode 표 (plan §Failure Modes) 기반.
+    """
+    # LLM 자가 refused → 모델이 준 사유 그대로
+    if sr.refused and sr.refuse_reason:
+        return sr.refuse_reason
+
+    # synthesis 상태 우선
+    if sr.status == "no_evidence":
+        if not pr.results:
+            return "검색 결과가 없습니다."
+        return "관련도 높은 근거를 찾지 못했습니다."
+    if sr.status == "skipped":
+        return "검색 결과가 없습니다."
+    if sr.status == "timeout":
+        return "답변 생성이 지연되어 생략했습니다. 검색 결과를 확인해 주세요."
+    if sr.status == "parse_failed":
+        return "답변 형식 오류로 생략했습니다."
+    if sr.status == "llm_error":
+        return "AI 서버에 일시적 문제가 있습니다."
+
+    # evidence 단계 실패는 fallback 을 탔더라도 notes 용
+    if ev_skip == "all_low_rerank":
+        return "관련도 높은 근거를 찾지 못했습니다."
+    if ev_skip == "empty_retrieval":
+        return "검색 결과가 없습니다."
+
+    return None
+
+
+def _build_citations(
+    evidence: list[EvidenceItem], used_citations: list[int]
+) -> list[Citation]:
+    """answer 본문에 실제로 등장한 n 만 Citation 으로 변환."""
+    by_n = {e.n: e for e in evidence}
+    out: list[Citation] = []
+    for n in used_citations:
+        e = by_n.get(n)
+        if e is None:
+            continue
+        out.append(
+            Citation(
+                n=e.n,
+                chunk_id=e.chunk_id,
+                doc_id=e.doc_id,
+                title=e.title,
+                section_title=e.section_title,
+                span_text=e.span_text,
+                full_snippet=e.full_snippet,
+                relevance=e.relevance,
+                rerank_score=e.rerank_score,
+            )
+        )
+    return out
+
+
+def _build_ask_debug(
+    pr: PipelineResult,
+    evidence: list[EvidenceItem],
+    ev_skip: str | None,
+    sr: SynthesisResult,
+    ev_ms: float,
+    synth_ms: float,
+    total_ms: float,
+) -> AskDebug:
+    timing: dict[str, float] = dict(pr.timing_ms)
+    timing["evidence_ms"] = ev_ms
+    timing["synthesis_ms"] = synth_ms
+    timing["ask_total_ms"] = total_ms
+
+    # candidate count 는 rule filter 통과한 수 (recomputable from results)
+    # 엄밀히는 evidence_service 내부 숫자인데, evidence 길이 ≈ kept, candidate
+    # 는 관측이 어려움 → kept 는 evidence 길이, candidate 는 별도 필드 없음.
+    # 단순화: candidate_count = len(evidence) 를 상한 근사로 둠 (debug 전용).
+    return AskDebug(
+        timing_ms=timing,
+        search_notes=pr.notes,
+        query_analysis=pr.query_analysis,
+        confidence_signal=pr.confidence_signal,
+        evidence_candidate_count=len(evidence),
+        evidence_kept_count=len(evidence),
+        evidence_skip_reason=ev_skip,
+        synthesis_cache_hit=sr.cache_hit,
+        synthesis_prompt_preview=None,  # 현재 synthesis_service 에서 노출 안 함
+        synthesis_raw_preview=sr.raw_preview,
+        hallucination_flags=sr.hallucination_flags,
+    )
+
+
+@router.get("/ask", response_model=AskResponse)
+async def ask(
+    q: str,
+    user: Annotated[User, Depends(get_current_user)],
+    session: Annotated[AsyncSession, Depends(get_session)],
+    background_tasks: BackgroundTasks,
+    limit: int = Query(10, ge=1, le=20, description="synthesis 입력 상한"),
+    debug: bool = Query(False, description="evidence/synthesis 중간 상태 노출"),
+):
+    """근거 기반 AI 답변 (Phase 3.3).
+
+    `/search` 와 동일한 검색 파이프라인을 거친 후 evidence extraction +
+    grounded synthesis 를 추가한다. `mode`, `rerank`, `analyze` 는 품질 보장을
+    위해 강제 고정 (hybrid / True / True).
+
+    실패 경로(timeout/parse_failed/refused/...) 에서도 `results` 는 항상 반환.
+    """
+    t_total = time.perf_counter()
+
+    # 1. 검색 파이프라인 (run_search — /search 와 동일 로직, 단일 진실 소스)
+    pr = await run_search(
+        session,
+        q,
+        mode="hybrid",
+        limit=limit,
+        fusion=DEFAULT_FUSION,
+        rerank=True,
+        analyze=True,
+    )
+
+    # 2. Evidence extraction (rule + LLM span select, 1 batched call)
+    t_ev = time.perf_counter()
+    evidence, ev_skip = await extract_evidence(q, pr.results)
+    ev_ms = (time.perf_counter() - t_ev) * 1000
+
+    # 3. Grounded synthesis (gemma-4, 15s timeout, citation 검증)
+    t_synth = time.perf_counter()
+    sr = await synthesize(q, evidence, debug=debug)
+    synth_ms = (time.perf_counter() - t_synth) * 1000
+
+    total_ms = (time.perf_counter() - t_total) * 1000
+
+    # 4. 응답 구성
+    citations = _build_citations(evidence, sr.used_citations)
+    no_reason = _map_no_results_reason(pr, evidence, ev_skip, sr)
+
+    logger.info(
+        "ask query=%r results=%d evidence=%d cite=%d synth=%s conf=%s refused=%s ev_ms=%.0f synth_ms=%.0f total=%.0f",
+        q[:80],
+        len(pr.results),
+        len(evidence),
+        len(citations),
+        sr.status,
+        sr.confidence or "-",
+        sr.refused,
+        ev_ms,
+        synth_ms,
+        total_ms,
+    )
+
+    # 5. telemetry — 기존 record_search_event 재사용 (Phase 0.3 호환)
+    background_tasks.add_task(
+        record_search_event,
+        q,
+        user.id,
+        pr.results,
+        "hybrid",
+        pr.confidence_signal,
+        pr.analyzer_confidence,
+    )
+
+    debug_obj = (
+        _build_ask_debug(pr, evidence, ev_skip, sr, ev_ms, synth_ms, total_ms)
+        if debug
+        else None
+    )
+
+    return AskResponse(
+        results=pr.results,
+        ai_answer=sr.answer,
+        citations=citations,
+        synthesis_status=sr.status,
+        synthesis_ms=sr.elapsed_ms,
+        confidence=sr.confidence,
+        refused=sr.refused,
+        no_results_reason=no_reason,
+        query=q,
+        total=len(pr.results),
         debug=debug_obj,
     )

app/core/database.py

@@ -95,7 +95,8 @@ async def _run_migrations(conn) -> None:
     applied = {row[0] for row in result}
 
     # migration 파일 스캔
-    migrations_dir = Path(__file__).resolve().parent.parent.parent / "migrations"
+    # /app/core/database.py → parent.parent = /app → /app/migrations (volume mount 위치)
+    migrations_dir = Path(__file__).resolve().parent.parent / "migrations"
     if not migrations_dir.is_dir():
         logger.info("[migration] migrations/ 디렉토리 없음, 스킵")
         return
@@ -114,7 +115,10 @@ async def _run_migrations(conn) -> None:
         sql = path.read_text(encoding="utf-8")
         _validate_sql_content(name, sql)
         logger.info(f"[migration] {name} 실행 중...")
-        await conn.execute(text(sql))
+        # raw driver SQL 사용 — text() 의 :name bind parameter 해석으로
+        # SQL 주석/literal 에 콜론이 들어가면 InvalidRequestError 발생.
+        # exec_driver_sql 은 SQL 을 driver(asyncpg) 에 그대로 전달.
+        await conn.exec_driver_sql(sql)
         await conn.execute(
             text("INSERT INTO schema_migrations (version, name) VALUES (:v, :n)"),
             {"v": version, "n": name},

app/main.py

@@ -8,6 +8,7 @@ from sqlalchemy import func, select, text
 
 from api.auth import router as auth_router
 from api.dashboard import router as dashboard_router
+from api.digest import router as digest_router
 from api.documents import router as documents_router
 from api.news import router as news_router
 from api.search import router as search_router
@@ -20,9 +21,13 @@ from models.user import User
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     """앱 시작/종료 시 실행되는 lifespan 핸들러"""
+    import asyncio
+
     from apscheduler.schedulers.asyncio import AsyncIOScheduler
     from apscheduler.triggers.cron import CronTrigger
+    from services.search.query_analyzer import prewarm_analyzer
     from workers.daily_digest import run as daily_digest_run
+    from workers.digest_worker import run as global_digest_run
     from workers.file_watcher import watch_inbox
     from workers.law_monitor import run as law_monitor_run
     from workers.mailplus_archive import run as mailplus_run
@@ -51,9 +56,19 @@ async def lifespan(app: FastAPI):
     scheduler.add_job(mailplus_run, CronTrigger(hour=7), id="mailplus_morning")
     scheduler.add_job(mailplus_run, CronTrigger(hour=18), id="mailplus_evening")
     scheduler.add_job(daily_digest_run, CronTrigger(hour=20), id="daily_digest")
+    scheduler.add_job(global_digest_run, CronTrigger(hour=4, minute=0), id="global_digest")
     scheduler.add_job(news_collector_run, "interval", hours=6, id="news_collector")
     scheduler.start()
 
+    # Phase 2.1 (async 구조): QueryAnalyzer prewarm.
+    # 대표 쿼리 15~20개를 background task로 분석해 cache 적재.
+    # 첫 사용자 요청부터 cache hit rate 70~80% 목표.
+    # 논블로킹 — startup을 막지 않음. MLX 부하 완화 위해 delay_between=0.5.
+    prewarm_task = asyncio.create_task(prewarm_analyzer())
+    prewarm_task.add_done_callback(
+        lambda t: t.exception() and None  # 예외는 query_analyzer 내부에서 로깅
+    )
+
     yield
 
     # 종료: 스케줄러 → DB 순서로 정리
@@ -76,6 +91,7 @@ app.include_router(search_router, prefix="/api/search", tags=["search"])
 
 app.include_router(dashboard_router, prefix="/api/dashboard", tags=["dashboard"])
 app.include_router(news_router, prefix="/api/news", tags=["news"])
+app.include_router(digest_router, prefix="/api/digest", tags=["digest"])
 
 # TODO: Phase 5에서 추가
 # app.include_router(tasks.router, prefix="/api/tasks", tags=["tasks"])

app/models/digest.py

@@ -0,0 +1,87 @@
+"""global_digests + digest_topics 테이블 ORM (Phase 4)"""
+
+from datetime import date, datetime
+
+from sqlalchemy import (
+    BigInteger,
+    Boolean,
+    Date,
+    DateTime,
+    Float,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+)
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from core.database import Base
+
+
+class GlobalDigest(Base):
+    """하루 단위 digest run 메타데이터"""
+
+    __tablename__ = "global_digests"
+
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
+    digest_date: Mapped[date] = mapped_column(Date, nullable=False, unique=True)
+    window_start: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    window_end: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    decay_lambda: Mapped[float] = mapped_column(Float, nullable=False)
+
+    total_articles: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    total_countries: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    total_topics: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+
+    generation_ms: Mapped[int | None] = mapped_column(Integer)
+    llm_calls: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    llm_failures: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    status: Mapped[str] = mapped_column(String(20), nullable=False, default="success")
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=datetime.now
+    )
+
+    topics: Mapped[list["DigestTopic"]] = relationship(
+        back_populates="digest",
+        cascade="all, delete-orphan",
+        order_by="DigestTopic.country, DigestTopic.topic_rank",
+    )
+
+
+class DigestTopic(Base):
+    """country × topic 단위 cluster 결과"""
+
+    __tablename__ = "digest_topics"
+
+    id: Mapped[int] = mapped_column(BigInteger, primary_key=True)
+    digest_id: Mapped[int] = mapped_column(
+        BigInteger,
+        ForeignKey("global_digests.id", ondelete="CASCADE"),
+        nullable=False,
+    )
+
+    country: Mapped[str] = mapped_column(String(10), nullable=False)
+    topic_rank: Mapped[int] = mapped_column(Integer, nullable=False)
+
+    topic_label: Mapped[str] = mapped_column(Text, nullable=False)
+    summary: Mapped[str] = mapped_column(Text, nullable=False)
+
+    article_ids: Mapped[list] = mapped_column(JSONB, nullable=False)
+    article_count: Mapped[int] = mapped_column(Integer, nullable=False)
+
+    importance_score: Mapped[float] = mapped_column(Float, nullable=False)
+    raw_weight_sum: Mapped[float] = mapped_column(Float, nullable=False)
+
+    centroid_sample: Mapped[dict | None] = mapped_column(JSONB)
+    llm_model: Mapped[str | None] = mapped_column(String(100))
+    llm_fallback_used: Mapped[bool] = mapped_column(
+        Boolean, nullable=False, default=False
+    )
+
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=datetime.now
+    )
+
+    digest: Mapped["GlobalDigest"] = relationship(back_populates="topics")

app/prompts/digest_topic.txt

@@ -0,0 +1,19 @@
+너는 팩트 기반 뉴스 토픽 요약 도우미다.
+아래는 같은 사건으로 군집된 기사들의 ai_summary다.
+이 정보만으로 다음을 JSON으로만 출력하라.
+
+절대 금지:
+- 제공된 summary에 없는 사실 추가
+- 해석/비교/예측/의견
+- "보인다", "~할 것이다", "~할 전망" 같은 추측 표현
+- 인용부호 안 원문 외 단어 생성
+- JSON 외의 모든 텍스트 (설명, 마크다운, 코드블록 금지)
+
+출력 형식 (JSON 객체 하나만 출력):
+{
+  "topic_label": "5~10 단어의 한국어 제목",
+  "summary": "1~2 문장, 사실만, 수동태 허용"
+}
+
+기사 요약:
+{articles_block}

app/prompts/evidence_extract.txt

@@ -0,0 +1,76 @@
+You are an evidence span extractor. Respond ONLY in JSON. No markdown, no explanation.
+
+## Task
+
+For each numbered candidate, extract the most query-relevant span from the original text (copy verbatim, 50-200 chars) and rate relevance 0.0~1.0. If the candidate does not directly answer the query, set span=null, relevance=0.0, skip_reason.
+
+## Output Schema
+{
+  "items": [
+    {
+      "n": 1,
+      "span": "...",
+      "relevance": 0.0,
+      "skip_reason": null
+    }
+  ]
+}
+
+## Rules
+- `n`: candidate 번호 (1-based, 입력 순서와 동일). **모든 n을 반환** (skip된 것도 포함).
+- `span`: 원문에서 **그대로 복사한** 50~200자. 요약/변형 금지. 원문에 없는 단어는 절대 포함하지 말 것. 여러 문장이어도 무방.
+- 관련 span이 없으면 `span: null`, `relevance: 0.0`, `skip_reason`에 한 줄 사유.
+- `relevance`: 0.0~1.0 float
+  - 0.9+ query에 직접 답함
+  - 0.7~0.9 강한 연관
+  - 0.5~0.7 부분 연관
+  - <0.5 약한/무관 (fallback에서 탈락)
+- `skip_reason`: span=null 일 때만 필수. 예: "no_direct_relevance", "off_topic", "generic_boilerplate"
+- **원문 그대로 복사 강제**: 번역/paraphrase/요약 모두 금지. evidence span은 citation 원문이 되어야 한다.
+
+## Example 1 (hit)
+query: `산업안전보건법 제6장 주요 내용`
+candidates:
+[1] title: 산업안전보건법 해설 / text: 제6장은 "안전보건관리체제"에 관한 장으로, 사업주의 안전보건관리책임자 선임 의무와 관리감독자 지정 등을 규정한다. 제15조부터 제19조까지 구성된다...
+[2] title: 회사 복지 규정 / text: 직원의 연차휴가 사용 규정과 경조사 지원 내용을 담고 있다...
+
+→
+{
+  "items": [
+    {
+      "n": 1,
+      "span": "제6장은 \"안전보건관리체제\"에 관한 장으로, 사업주의 안전보건관리책임자 선임 의무와 관리감독자 지정 등을 규정한다. 제15조부터 제19조까지 구성된다",
+      "relevance": 0.95,
+      "skip_reason": null
+    },
+    {
+      "n": 2,
+      "span": null,
+      "relevance": 0.0,
+      "skip_reason": "off_topic"
+    }
+  ]
+}
+
+## Example 2 (partial)
+query: `Python async best practice`
+candidates:
+[1] title: FastAPI tutorial / text: FastAPI supports both async and sync endpoints. For I/O-bound operations, use async def with await for database and HTTP calls. Avoid blocking calls in async functions or use run_in_executor...
+
+→
+{
+  "items": [
+    {
+      "n": 1,
+      "span": "For I/O-bound operations, use async def with await for database and HTTP calls. Avoid blocking calls in async functions or use run_in_executor",
+      "relevance": 0.82,
+      "skip_reason": null
+    }
+  ]
+}
+
+## Query
+{query}
+
+## Candidates
+{numbered_candidates}

app/prompts/query_analyze.txt

@@ -0,0 +1,53 @@
+You are a search query analyzer. Respond ONLY in JSON. No markdown, no explanation.
+
+## Output Schema
+{
+  "intent": "fact_lookup | semantic_search | filter_browse",
+  "query_type": "natural_language | keyword | phrase",
+  "domain_hint": "document | news | mixed",
+  "language_scope": "limited | global",
+  "keywords": [],
+  "must_terms": [],
+  "optional_terms": [],
+  "hard_filters": {},
+  "soft_filters": {"domain": [], "document_type": []},
+  "normalized_queries": [{"lang": "ko", "text": "...", "weight": 1.0}],
+  "expanded_terms": [],
+  "synonyms": {},
+  "analyzer_confidence": 0.0
+}
+
+## Rules
+- `intent`: fact_lookup (사실/조항/이름), semantic_search (주제/개념), filter_browse (필터 중심)
+- `query_type`: natural_language (문장형), keyword (단어 나열), phrase (따옴표/고유명사/법조항)
+- `domain_hint`: document (소유 문서/법령/매뉴얼), news (시사/뉴스), mixed (불명)
+- `language_scope`: limited (ko+en), global (다국어 필요)
+- `hard_filters`: 쿼리에 **명시된** 것만. 추론 금지. 키: file_format, year, country
+- `soft_filters.domain`: Industrial_Safety, Programming, Engineering, Philosophy, Language, General. 2-level 허용(e.g. Industrial_Safety/Legislation)
+- `soft_filters.document_type`: Law_Document, Manual, Report, Academic_Paper, Standard, Specification, Meeting_Minutes, Checklist, Note, Memo, Reference, Drawing, Template
+- `normalized_queries`: 원문 언어 1.0 가중치 필수. 교차언어 1개 추가 권장(ko↔en, weight 0.8). news + global 인 경우만 ja/zh 추가(weight 0.5~0.6). **최대 3개**.
+- `analyzer_confidence`: 0.9+ 명확, 0.7~0.9 대체로 명확, 0.5~0.7 모호, <0.5 분석 불가
+
+## Example
+query: `기계 사고 관련 법령`
+{
+  "intent": "semantic_search",
+  "query_type": "natural_language",
+  "domain_hint": "document",
+  "language_scope": "limited",
+  "keywords": ["기계", "사고", "법령"],
+  "must_terms": [],
+  "optional_terms": ["안전", "규정"],
+  "hard_filters": {},
+  "soft_filters": {"domain": ["Industrial_Safety/Legislation"], "document_type": ["Law_Document"]},
+  "normalized_queries": [
+    {"lang": "ko", "text": "기계 사고 관련 법령", "weight": 1.0},
+    {"lang": "en", "text": "machinery accident related laws", "weight": 0.8}
+  ],
+  "expanded_terms": ["산업안전", "기계안전"],
+  "synonyms": {},
+  "analyzer_confidence": 0.88
+}
+
+## Query
+{query}

app/prompts/search_synthesis.txt

@@ -0,0 +1,80 @@
+You are a grounded answer synthesizer. Respond ONLY in JSON. No markdown, no explanation.
+
+## Task
+
+Given a query and numbered evidence spans, write a short answer that cites specific evidence by [n]. **You may only use facts that appear in the evidence.** If the evidence does not directly answer the query, set `refused: true`.
+
+## Output Schema
+{
+  "answer": "...",
+  "used_citations": [1, 2],
+  "confidence": "high",
+  "refused": false,
+  "refuse_reason": null
+}
+
+## Rules
+- `answer`: **400 characters max**. Must contain inline `[n]` citations. Every claim sentence ends with at least one `[n]`. Multiple sources: `[1][3]`. **Only use facts present in evidence. No outside knowledge, no guessing, no paraphrasing what is not there.**
+- `used_citations`: integer list of `n` values that actually appear in `answer` (for cross-check). Must be sorted ascending, no duplicates.
+- `confidence`:
+  - `high`: 3+ evidence items directly match the query
+  - `medium`: 2 items match, or strong single match
+  - `low`: 1 weak item, or partial match
+- `refused`: set to `true` if evidence does not directly answer the query (e.g. off-topic, too generic, missing key facts). When refused:
+  - `answer`: empty string `""`
+  - `used_citations`: `[]`
+  - `confidence`: `"low"`
+  - `refuse_reason`: one sentence explaining why (will be shown to the user)
+- **Language**: Korean query → Korean answer. English query → English answer. Match query language.
+- **Absolute prohibition**: Do NOT introduce entities, numbers, dates, or claims that are not verbatim in the evidence. If you are unsure whether a fact is in evidence, treat it as not present and either omit it or refuse.
+
+## Example 1 (happy path, high confidence)
+query: `산업안전보건법 제6장 주요 내용`
+evidence:
+[1] 산업안전보건법 해설: 제6장은 "안전보건관리체제"에 관한 장으로, 사업주의 안전보건관리책임자 선임 의무와 관리감독자 지정 등을 규정한다
+[2] 시행령 해설: 제6장은 제15조부터 제19조까지로 구성되며 안전보건관리책임자의 업무 범위를 세부 규정한다
+[3] 법령 체계도: 안전보건관리책임자 선임은 상시근로자 50명 이상 사업장에 적용된다
+
+→
+{
+  "answer": "산업안전보건법 제6장은 안전보건관리체제에 관한 장으로, 사업주의 안전보건관리책임자 선임 의무와 관리감독자 지정을 규정한다[1]. 제15조부터 제19조까지 구성되며 관리책임자의 업무 범위를 세부 규정한다[2]. 상시근로자 50명 이상 사업장에 적용된다[3].",
+  "used_citations": [1, 2, 3],
+  "confidence": "high",
+  "refused": false,
+  "refuse_reason": null
+}
+
+## Example 2 (partial, medium confidence)
+query: `Python async best practice`
+evidence:
+[1] FastAPI tutorial: For I/O-bound operations, use async def with await for database and HTTP calls. Avoid blocking calls in async functions or use run_in_executor
+
+→
+{
+  "answer": "For I/O-bound operations, use async def with await for database and HTTP calls, and avoid blocking calls inside async functions (use run_in_executor instead) [1].",
+  "used_citations": [1],
+  "confidence": "low",
+  "refused": false,
+  "refuse_reason": null
+}
+
+## Example 3 (refused — evidence does not answer query)
+query: `회사 연차 휴가 사용 규정`
+evidence:
+[1] 산업안전보건법 해설: 제6장은 "안전보건관리체제"에 관한 장으로, 사업주의 안전보건관리책임자 선임 의무와 관리감독자 지정 등을 규정한다
+[2] 회사 복지 안내: 직원 경조사 지원 내용 포함
+
+→
+{
+  "answer": "",
+  "used_citations": [],
+  "confidence": "low",
+  "refused": true,
+  "refuse_reason": "연차 휴가 사용 규정에 대한 직접적인 근거가 evidence에 없습니다."
+}
+
+## Query
+{query}
+
+## Evidence
+{numbered_evidence}

app/services/digest/__init__.py

@@ -0,0 +1 @@
+"""Phase 4 Global Digest 서비스 레이어 — 7일 뉴스 batch clustering + summarization."""

app/services/digest/clustering.py

@@ -0,0 +1,118 @@
+"""Time-decay weight + adaptive threshold + EMA centroid greedy clustering.
+
+플랜의 핵심 결정:
+- λ = ln(2)/3 (3일 반감기)
+- threshold: 0.75 / 0.78 / 0.80 (밀도 기반 adaptive)
+- centroid: EMA α=0.7 (단순 평균의 seed bias / drift 방어)
+- min_articles_per_topic = 3, max_topics_per_country = 10
+- importance_score: country 내 0~1 normalize + max(score, 0.01) floor
+- raw_weight_sum 별도 보존 (cross-day 트렌드 분석용)
+"""
+
+import math
+from datetime import datetime, timezone
+
+import numpy as np
+
+from core.utils import setup_logger
+
+logger = setup_logger("digest_clustering")
+
+LAMBDA = math.log(2) / 3        # 3일 반감기 — 사용자 확정값
+CENTROID_ALPHA = 0.7            # EMA: 기존 중심 70% 유지, 새 멤버 30% 반영
+MIN_ARTICLES_PER_TOPIC = 3
+MAX_TOPICS_PER_COUNTRY = 10
+SCORE_FLOOR = 0.01              # UI 0 표시 문제 사전 차단
+
+
+def adaptive_threshold(n_docs: int) -> float:
+    """문서 밀도 기반 동적 threshold — fragmentation/blob 동시 방어."""
+    if n_docs > 200:
+        return 0.80
+    if n_docs < 50:
+        return 0.75
+    return 0.78
+
+
+def _normalize(v: np.ndarray) -> np.ndarray:
+    norm = float(np.linalg.norm(v))
+    if norm == 0.0:
+        return v
+    return v / norm
+
+
+def _decay_weight(now: datetime, created_at: datetime) -> float:
+    """exp(-λ * days_ago). created_at 이 naive 면 UTC 가정."""
+    if created_at.tzinfo is None:
+        created_at = created_at.replace(tzinfo=timezone.utc)
+    days = (now - created_at).total_seconds() / 86400.0
+    if days < 0:
+        days = 0.0
+    return math.exp(-LAMBDA * days)
+
+
+def cluster_country(country: str, docs: list[dict]) -> list[dict]:
+    """단일 country 의 docs 를 cluster 로 묶어 정렬 + normalize 후 반환.
+
+    Args:
+        country: 국가 코드 (KR, US, ...)
+        docs: loader.load_news_window 의 출력 (단일 country 슬라이스)
+
+    Returns:
+        [{centroid, members, weight_sum, raw_weight_sum, importance_score}, ...]
+        - members 는 weight 가 채워진 doc dict 리스트
+        - 정렬: importance_score 내림차순, 최대 MAX_TOPICS_PER_COUNTRY 개
+    """
+    if not docs:
+        logger.info(f"[{country}] docs=0 → skip")
+        return []
+
+    threshold = adaptive_threshold(len(docs))
+    now = datetime.now(timezone.utc)
+
+    # time-decay weight 계산 + 가중치 높은 순으로 seed 우선
+    for d in docs:
+        d["weight"] = _decay_weight(now, d["created_at"])
+    docs.sort(key=lambda d: -d["weight"])
+
+    clusters: list[dict] = []
+    for d in docs:
+        v = _normalize(d["embedding"])
+        best_idx, best_sim = -1, 0.0
+        for i, c in enumerate(clusters):
+            sim = float(np.dot(c["centroid"], v))
+            if sim > best_sim and sim >= threshold:
+                best_sim, best_idx = sim, i
+        if best_idx >= 0:
+            c = clusters[best_idx]
+            # EMA centroid update — drift 방지
+            c["centroid"] = CENTROID_ALPHA * c["centroid"] + (1.0 - CENTROID_ALPHA) * v
+            c["centroid"] = _normalize(c["centroid"])
+            c["members"].append(d)
+            c["weight_sum"] += d["weight"]
+        else:
+            clusters.append({
+                "centroid": v,
+                "members": [d],
+                "weight_sum": d["weight"],
+            })
+
+    raw_count = len(clusters)
+    clusters = [c for c in clusters if len(c["members"]) >= MIN_ARTICLES_PER_TOPIC]
+    dropped = raw_count - len(clusters)
+    clusters.sort(key=lambda c: -c["weight_sum"])
+    clusters = clusters[:MAX_TOPICS_PER_COUNTRY]
+
+    # country 내 normalize (0~1) + floor
+    if clusters:
+        max_w = max(c["weight_sum"] for c in clusters)
+        for c in clusters:
+            normalized = (c["weight_sum"] / max_w) if max_w > 0 else 0.0
+            c["raw_weight_sum"] = c["weight_sum"]
+            c["importance_score"] = max(normalized, SCORE_FLOOR)
+
+    logger.info(
+        f"[{country}] docs={len(docs)} threshold={threshold} "
+        f"raw_clusters={raw_count} dropped={dropped} kept={len(clusters)}"
+    )
+    return clusters

app/services/digest/loader.py

@@ -0,0 +1,149 @@
+"""뉴스 7일 window 로드 + country 정규화
+
+- documents 테이블엔 country 컬럼이 없으므로 document_chunks.country 를 first non-null 로 조인.
+- chunk-level country 도 NULL 이면 news_sources.name prefix(ai_sub_group) 매칭으로 fallback.
+- 그래도 NULL 이면 drop(로그 경고).
+- ai_summary / embedding 이 NULL 이면 처음부터 제외 (재요약/재임베딩 0회 원칙).
+"""
+
+from collections import defaultdict
+from datetime import datetime
+from typing import Any
+
+import numpy as np
+from sqlalchemy import text
+
+from core.database import async_session
+from core.utils import setup_logger
+
+logger = setup_logger("digest_loader")
+
+
+_NEWS_WINDOW_SQL = text("""
+    SELECT
+        d.id,
+        d.title,
+        d.ai_summary,
+        d.embedding,
+        d.created_at,
+        d.edit_url,
+        d.ai_sub_group,
+        (
+            SELECT c.country
+            FROM document_chunks c
+            WHERE c.doc_id = d.id AND c.country IS NOT NULL
+            LIMIT 1
+        ) AS chunk_country
+    FROM documents d
+    WHERE d.source_channel = 'news'
+      AND d.deleted_at IS NULL
+      AND d.created_at >= :window_start
+      AND d.created_at < :window_end
+      AND d.embedding IS NOT NULL
+      AND d.ai_summary IS NOT NULL
+""")
+
+
+_SOURCE_COUNTRY_SQL = text("""
+    SELECT name, country FROM news_sources WHERE country IS NOT NULL
+""")
+
+
+def _to_numpy_embedding(raw: Any) -> np.ndarray | None:
+    """pgvector 컬럼을 numpy array(float32)로 정규화.
+
+    raw SQL + asyncpg 조합에서 pgvector type 이 등록 안 되어 있으면
+    embedding 이 '[0.1,0.2,...]' 같은 string 으로 반환된다. ORM 을 안 쓰므로
+    이 경우 직접 파싱해야 한다.
+    """
+    if raw is None:
+        return None
+    if isinstance(raw, str):
+        import json
+        try:
+            raw = json.loads(raw)
+        except json.JSONDecodeError:
+            return None
+    try:
+        arr = np.asarray(raw, dtype=np.float32)
+    except (TypeError, ValueError):
+        return None
+    if arr.size == 0:
+        return None
+    return arr
+
+
+async def _load_source_country_map(session) -> dict[str, str]:
+    """news_sources name → country 매핑.
+
+    name 은 '경향신문 문화' 형태이고 documents.ai_sub_group 은 '경향신문' (split[0]).
+    prefix 매칭이 가능하도록 첫 토큰 → country 로 인덱싱.
+    """
+    rows = await session.execute(_SOURCE_COUNTRY_SQL)
+    mapping: dict[str, str] = {}
+    for name, country in rows:
+        if not name or not country:
+            continue
+        prefix = name.split(" ")[0].strip()
+        if prefix and prefix not in mapping:
+            mapping[prefix] = country
+    return mapping
+
+
+async def load_news_window(
+    window_start: datetime,
+    window_end: datetime,
+) -> dict[str, list[dict]]:
+    """주어진 윈도우 안의 뉴스 documents 를 country 별 dict 로 반환.
+
+    Returns:
+        {"KR": [doc_dict, ...], "US": [...], ...}
+    """
+    docs_by_country: dict[str, list[dict]] = defaultdict(list)
+    null_country_count = 0
+    total = 0
+
+    async with async_session() as session:
+        source_country = await _load_source_country_map(session)
+
+        result = await session.execute(
+            _NEWS_WINDOW_SQL,
+            {"window_start": window_start, "window_end": window_end},
+        )
+        for row in result.mappings():
+            embedding = _to_numpy_embedding(row["embedding"])
+            if embedding is None:
+                continue
+
+            country = row["chunk_country"]
+            if not country:
+                # news_sources prefix fallback
+                ai_sub_group = (row["ai_sub_group"] or "").strip()
+                if ai_sub_group:
+                    country = source_country.get(ai_sub_group)
+            if not country:
+                null_country_count += 1
+                continue
+
+            country = country.upper()
+            docs_by_country[country].append({
+                "id": int(row["id"]),
+                "title": row["title"] or "",
+                "ai_summary": row["ai_summary"] or "",
+                "embedding": embedding,
+                "created_at": row["created_at"],
+                "edit_url": row["edit_url"] or "",
+                "ai_sub_group": row["ai_sub_group"] or "",
+            })
+            total += 1
+
+    if null_country_count:
+        logger.warning(
+            f"[loader] country 분류 실패로 drop된 문서 {null_country_count}건 "
+            f"(chunk_country + news_sources fallback 모두 실패)"
+        )
+    logger.info(
+        f"[loader] window {window_start.date()} ~ {window_end.date()} → "
+        f"{total}건 ({len(docs_by_country)}개 국가)"
+    )
+    return dict(docs_by_country)

app/services/digest/pipeline.py

@@ -0,0 +1,177 @@
+"""Phase 4 digest pipeline orchestration.
+
+Step:
+    1. AIClient 생성
+    2. 7일 window 로 documents 로드 (loader)
+    3. country 별 cluster_country (clustering)
+    4. cluster 별 select_for_llm (selection)
+    5. cluster 별 summarize_cluster_with_fallback (summarizer, LLM)
+    6. DELETE+INSERT 단일 트랜잭션 (idempotent)
+    7. start/end 로그 + generation_ms + fallback 비율 health metric
+"""
+
+import hashlib
+import time
+from datetime import datetime, timedelta, timezone
+from zoneinfo import ZoneInfo
+
+from sqlalchemy import delete
+
+from ai.client import AIClient
+from core.database import async_session
+from core.utils import setup_logger
+from models.digest import DigestTopic, GlobalDigest
+
+from .clustering import LAMBDA, cluster_country
+from .loader import load_news_window
+from .selection import select_for_llm
+from .summarizer import summarize_cluster_with_fallback
+
+logger = setup_logger("digest_pipeline")
+
+WINDOW_DAYS = 7
+KST = ZoneInfo("Asia/Seoul")
+
+
+def _kst_today() -> datetime:
+    return datetime.now(KST).date()
+
+
+def _summary_hash(text: str) -> str:
+    return hashlib.sha256((text or "").encode("utf-8")).hexdigest()[:16]
+
+
+def _build_topic_row(
+    country: str,
+    rank: int,
+    cluster: dict,
+    selected: list[dict],
+    llm_result: dict,
+    primary_model: str,
+) -> DigestTopic:
+    """LLM 결과 + cluster 메타 → DigestTopic ORM 인스턴스.
+
+    article_ids 는 코드가 cluster.members 에서 직접 주입 (LLM 생성 금지 → id 위조 불가).
+    """
+    article_ids = [int(m["id"]) for m in cluster["members"]]
+    centroid_sample = {
+        "selected_doc_ids": [int(m["id"]) for m in selected],
+        "summary_hashes": [_summary_hash(m.get("ai_summary") or "") for m in selected],
+    }
+    return DigestTopic(
+        country=country,
+        topic_rank=rank,
+        topic_label=llm_result["topic_label"],
+        summary=llm_result["summary"],
+        article_ids=article_ids,
+        article_count=len(article_ids),
+        importance_score=float(cluster["importance_score"]),
+        raw_weight_sum=float(cluster["raw_weight_sum"]),
+        centroid_sample=centroid_sample,
+        llm_model=primary_model,
+        llm_fallback_used=bool(llm_result["llm_fallback_used"]),
+    )
+
+
+async def run_digest_pipeline() -> dict:
+    """전체 파이프라인 실행. worker entry 에서 호출.
+
+    Returns:
+        실행 통계 dict {llm_calls, fallback_used, total_topics, generation_ms}
+    """
+    start = time.time()
+
+    window_end = datetime.now(timezone.utc)
+    window_start = window_end - timedelta(days=WINDOW_DAYS)
+    digest_date = _kst_today()
+
+    logger.info(
+        f"[global_digest] start window={window_start.date()} ~ {window_end.date()} "
+        f"digest_date={digest_date} decay_lambda={LAMBDA:.4f}"
+    )
+
+    docs_by_country = await load_news_window(window_start, window_end)
+    if not docs_by_country:
+        logger.warning("[global_digest] 7일 window에 뉴스 0건 — digest 생성 스킵")
+        return {
+            "llm_calls": 0,
+            "fallback_used": 0,
+            "total_topics": 0,
+            "generation_ms": int((time.time() - start) * 1000),
+        }
+
+    client = AIClient()
+    primary_model = client.ai.primary.model
+
+    all_topic_rows: list[DigestTopic] = []
+    stats = {"llm_calls": 0, "fallback_used": 0}
+
+    try:
+        for country, docs in docs_by_country.items():
+            clusters = cluster_country(country, docs)
+            if not clusters:
+                continue  # sparse country 자동 제외
+
+            for rank, cluster in enumerate(clusters, start=1):
+                selected = select_for_llm(cluster)
+                stats["llm_calls"] += 1
+                llm_result = await summarize_cluster_with_fallback(client, cluster, selected)
+                if llm_result["llm_fallback_used"]:
+                    stats["fallback_used"] += 1
+                all_topic_rows.append(
+                    _build_topic_row(country, rank, cluster, selected, llm_result, primary_model)
+                )
+    finally:
+        await client.close()
+
+    generation_ms = int((time.time() - start) * 1000)
+    total_articles = sum(len(d) for d in docs_by_country.values())
+    countries_with_topics = len({r.country for r in all_topic_rows})
+
+    if stats["fallback_used"] == 0:
+        status = "success"
+    elif stats["llm_calls"] and stats["fallback_used"] / stats["llm_calls"] > 0.5:
+        status = "failed"
+    else:
+        status = "partial"
+
+    async with async_session() as session:
+        # idempotent: 같은 날짜 row 가 있으면 CASCADE 로 topics 까지 삭제
+        await session.execute(
+            delete(GlobalDigest).where(GlobalDigest.digest_date == digest_date)
+        )
+        new_digest = GlobalDigest(
+            digest_date=digest_date,
+            window_start=window_start,
+            window_end=window_end,
+            decay_lambda=LAMBDA,
+            total_articles=total_articles,
+            total_countries=countries_with_topics,
+            total_topics=len(all_topic_rows),
+            generation_ms=generation_ms,
+            llm_calls=stats["llm_calls"],
+            llm_failures=stats["fallback_used"],
+            status=status,
+        )
+        new_digest.topics = all_topic_rows
+        session.add(new_digest)
+        await session.commit()
+
+    fallback_pct = (
+        (stats["fallback_used"] / stats["llm_calls"] * 100.0)
+        if stats["llm_calls"] else 0.0
+    )
+    logger.info(
+        f"[global_digest] done countries={countries_with_topics} "
+        f"topics={len(all_topic_rows)} llm_calls={stats['llm_calls']} "
+        f"fallback={stats['fallback_used']}/{stats['llm_calls']} ({fallback_pct:.2f}%) "
+        f"status={status} elapsed={generation_ms / 1000:.1f}s"
+    )
+
+    return {
+        "llm_calls": stats["llm_calls"],
+        "fallback_used": stats["fallback_used"],
+        "total_topics": len(all_topic_rows),
+        "generation_ms": generation_ms,
+        "status": status,
+    }

app/services/digest/selection.py

@@ -0,0 +1,62 @@
+"""Cluster 내 LLM 입력 선정 — top-k + MMR diversity + ai_summary truncate.
+
+순수 top-relevance 는 동일 사건 중복 요약문에 편향되므로 MMR 로 다양성 확보.
+ai_summary 길이는 LLM 토큰 보호를 위해 SUMMARY_TRUNCATE 로 제한.
+"""
+
+import numpy as np
+
+K_PER_CLUSTER = 5
+LAMBDA_MMR = 0.7         # relevance 70% / diversity 30%
+SUMMARY_TRUNCATE = 300   # long tail ai_summary 방어
+
+
+def _normalize(v: np.ndarray) -> np.ndarray:
+    norm = float(np.linalg.norm(v))
+    if norm == 0.0:
+        return v
+    return v / norm
+
+
+def select_for_llm(cluster: dict, k: int = K_PER_CLUSTER) -> list[dict]:
+    """cluster 내 LLM 호출용 대표 article 들 선정.
+
+    Args:
+        cluster: clustering.cluster_country 결과 단일 cluster
+        k: 선정 개수 (기본 5)
+
+    Returns:
+        선정된 doc dict 리스트. 각 항목에 ai_summary_truncated 필드가 추가됨.
+    """
+    members = cluster["members"]
+    if len(members) <= k:
+        selected = list(members)
+    else:
+        centroid = cluster["centroid"]
+        # relevance = centroid 유사도 × decay weight
+        for m in members:
+            v = _normalize(m["embedding"])
+            m["_rel"] = float(np.dot(centroid, v)) * m["weight"]
+
+        first = max(members, key=lambda x: x["_rel"])
+        selected = [first]
+        candidates = [m for m in members if m is not first]
+
+        while len(selected) < k and candidates:
+            def mmr_score(c: dict) -> float:
+                v = _normalize(c["embedding"])
+                max_sim = max(
+                    float(np.dot(v, _normalize(s["embedding"])))
+                    for s in selected
+                )
+                return LAMBDA_MMR * c["_rel"] - (1.0 - LAMBDA_MMR) * max_sim
+
+            pick = max(candidates, key=mmr_score)
+            selected.append(pick)
+            candidates.remove(pick)
+
+    # LLM 입력 토큰 보호
+    for m in selected:
+        m["ai_summary_truncated"] = (m.get("ai_summary") or "")[:SUMMARY_TRUNCATE]
+
+    return selected

app/services/digest/summarizer.py

@@ -0,0 +1,123 @@
+"""Cluster-level LLM 호출 + JSON 파싱 + timeout + drop금지 fallback.
+
+핵심 결정:
+- AIClient._call_chat 직접 호출 (client.py 수정 회피, fallback 로직 재사용)
+- Semaphore(1) 로 MLX 과부하 회피
+- Per-call timeout 25초 (asyncio.wait_for) — MLX hang/Ollama stall 방어
+- JSON 파싱 실패 → 1회 재시도 → 그래도 실패 시 minimal fallback (drop 금지)
+- fallback: topic_label="주요 뉴스 묶음", summary = top member ai_summary[:200]
+"""
+
+import asyncio
+from pathlib import Path
+from typing import Any
+
+from ai.client import parse_json_response
+from core.utils import setup_logger
+
+logger = setup_logger("digest_summarizer")
+
+LLM_CALL_TIMEOUT = 25       # 초. MLX 평균 5초 + tail latency 마진
+FALLBACK_SUMMARY_LIMIT = 200
+
+_llm_sem = asyncio.Semaphore(1)
+
+_PROMPT_PATH = Path(__file__).resolve().parent.parent.parent / "prompts" / "digest_topic.txt"
+_PROMPT_TEMPLATE: str | None = None
+
+
+def _load_prompt() -> str:
+    global _PROMPT_TEMPLATE
+    if _PROMPT_TEMPLATE is None:
+        _PROMPT_TEMPLATE = _PROMPT_PATH.read_text(encoding="utf-8")
+    return _PROMPT_TEMPLATE
+
+
+def build_prompt(selected: list[dict]) -> str:
+    """digest_topic.txt 템플릿에 selected article들의 ai_summary_truncated 주입.
+
+    템플릿 placeholder: {articles_block}
+    """
+    template = _load_prompt()
+    lines = []
+    for i, m in enumerate(selected, start=1):
+        text = (m.get("ai_summary_truncated") or m.get("ai_summary") or m.get("title") or "").strip()
+        lines.append(f"[{i}] {text}")
+    articles_block = "\n".join(lines)
+    return template.replace("{articles_block}", articles_block)
+
+
+async def _try_call_llm(client: Any, prompt: str) -> str:
+    """Semaphore + per-call timeout 으로 감싼 단일 호출."""
+    async with _llm_sem:
+        return await asyncio.wait_for(
+            client._call_chat(client.ai.primary, prompt),
+            timeout=LLM_CALL_TIMEOUT,
+        )
+
+
+def _make_fallback(cluster: dict) -> dict:
+    """cluster 의 top member 데이터로 minimal fallback 생성 — 정보 손실 회피."""
+    members = cluster["members"]
+    if not members:
+        return {
+            "topic_label": "주요 뉴스 묶음",
+            "summary": "",
+            "llm_fallback_used": True,
+        }
+    top = max(members, key=lambda m: m.get("_rel", m.get("weight", 0.0)))
+    text = (top.get("ai_summary") or top.get("title") or "").strip()
+    return {
+        "topic_label": "주요 뉴스 묶음",
+        "summary": text[:FALLBACK_SUMMARY_LIMIT],
+        "llm_fallback_used": True,
+    }
+
+
+async def summarize_cluster_with_fallback(
+    client: Any,
+    cluster: dict,
+    selected: list[dict],
+) -> dict:
+    """cluster 1개에 대해 LLM 호출 + JSON 파싱 + fallback.
+
+    Returns:
+        {topic_label, summary, llm_fallback_used}
+    """
+    prompt = build_prompt(selected)
+
+    for attempt in range(2):  # 1회 재시도 포함
+        try:
+            raw = await _try_call_llm(client, prompt)
+        except asyncio.TimeoutError:
+            logger.warning(
+                f"LLM 호출 timeout {LLM_CALL_TIMEOUT}s "
+                f"(attempt={attempt + 1}, cluster size={len(cluster['members'])})"
+            )
+            continue
+        except Exception as e:
+            logger.warning(
+                f"LLM 호출 실패 attempt={attempt + 1} "
+                f"(cluster size={len(cluster['members'])}): {e}"
+            )
+            continue
+
+        parsed = parse_json_response(raw)
+        if (
+            parsed
+            and isinstance(parsed.get("topic_label"), str)
+            and isinstance(parsed.get("summary"), str)
+            and parsed["topic_label"].strip()
+            and parsed["summary"].strip()
+        ):
+            return {
+                "topic_label": parsed["topic_label"].strip(),
+                "summary": parsed["summary"].strip(),
+                "llm_fallback_used": False,
+            }
+        logger.warning(
+            f"JSON 파싱 실패 attempt={attempt + 1} "
+            f"(cluster size={len(cluster['members'])}, raw_len={len(raw) if raw else 0})"
+        )
+
+    return _make_fallback(cluster)

app/services/search/evidence_service.py

@@ -1,5 +1,407 @@
-"""Evidence extraction 서비스 (Phase 3).
+"""Evidence extraction 서비스 (Phase 3.2).
 
-reranked chunks에서 query-relevant span을 rule + LLM hybrid로 추출.
-구현은 Phase 3에서 채움.
+reranker 결과 chunks 에서 query-relevant span 을 구조적으로 추출한다.
+
+## 설계 (EV-A: Rule + LLM span select)
+
+```
+reranked results
+    ↓
+[rule filter]   score >= 0.25, max_per_doc=2, top MAX_EVIDENCE_CANDIDATES
+    ↓
+[snippet 재윈도우]  _extract_window(full, query, 800) — LLM 입력용
+    ↓
+[1 batched LLM call]  gemma-4 via get_mlx_gate() (single inference)
+    ↓
+[post-process]
+  - relevance >= 0.5 필터
+  - span too-short (< 80자) → _extract_window(full, query, 120) 로 재확장
+  - span too-long (> 300자) → cut
+  - doc-group ordering (검색 결과 doc 순서 유지, doc 내부만 relevance desc)
+  - n 재부여 (1..N)
+    ↓
+EvidenceItem 리스트
+```
+
+## 영구 룰
+
+- **LLM 호출은 1번만** (batched). 순차 호출 절대 금지 — MLX single-inference
+  큐가 폭발한다.
+- **모든 MLX 호출은 `get_mlx_gate()` 경유**. analyzer / synthesis 와 동일
+  semaphore 공유.
+- **fallback span 도 query 중심 window**. `full_snippet[:200]` 같은 "앞에서부터
+  자르기" 절대 금지. 조용한 품질 붕괴 (citation 은 멀쩡한데 실제 span 이 query
+  와 무관) 대표 사례.
+- **Span too-short 보정 필수**: `len(span) < 80` 이면 자동 확장. "짧을수록
+  정확" 이 아니라 **짧으면 위험** — synthesis LLM 이 문맥 부족으로 이어 만들기
+  (soft hallucination) 를 한다.
+- **Evidence ordering 은 doc-group 유지**. 전역 relevance desc 정렬 금지.
+  answer 는 [1][2][3] 순서로 생성되고 그 순서가 문맥 흐름을 결정한다.
+
+## 확장 여지 (지금은 비활성)
+
+`EVIDENCE_FAST_PATH_THRESHOLD` 가 `None` 이 아니고 `results[0].rerank_score >=
+THRESHOLD` 이면 LLM 호출 스킵 후 rule-only 경로로 즉시 반환. Activation 조건:
+(1) evidence LLM 호출 비율 > 80%, (2) /ask 평균 latency > 15s, (3) rerank
+top1 p50 > 0.75. 셋 다 충족해야 켠다.
 """
+
+from __future__ import annotations
+
+import asyncio
+import time
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING
+
+from ai.client import AIClient, _load_prompt, parse_json_response
+from core.utils import setup_logger
+
+from .llm_gate import get_mlx_gate
+from .rerank_service import _extract_window
+
+if TYPE_CHECKING:
+    from api.search import SearchResult
+
+logger = setup_logger("evidence")
+
+# ─── 상수 (plan 영구 룰) ─────────────────────────────────
+EVIDENCE_MIN_RERANK = 0.25  # 1차 rule cut — rerank score 이 미만은 제외
+MAX_EVIDENCE_CANDIDATES = 6  # LLM 입력 상한
+MAX_PER_DOC = 2
+CANDIDATE_SNIPPET_CHARS = 800  # LLM 이 볼 원문 창 크기
+
+MIN_RELEVANCE_KEEP = 0.5  # LLM 출력 필터
+SPAN_MIN_CHARS = 80  # 이 미만이면 window enlarge
+SPAN_ENLARGE_TARGET = 120  # enlarge 시 재윈도우 target_chars
+SPAN_MAX_CHARS = 300  # 이 초과면 cut (synthesis token budget 보호)
+
+LLM_TIMEOUT_MS = 15000
+PROMPT_VERSION = "v1"
+
+# 확장 여지 — None 이면 비활성 (baseline). 실측 후 0.8 등으로 켠다.
+EVIDENCE_FAST_PATH_THRESHOLD: float | None = None
+
+
+# ─── 반환 타입 ───────────────────────────────────────────
+
+
+@dataclass(slots=True)
+class EvidenceItem:
+    """LLM 또는 rule fallback 이 추출한 단일 evidence span.
+
+    n 은 doc-group ordering + relevance 정렬 후 1부터 재부여된다.
+    `full_snippet` 은 **synthesis 프롬프트에 절대 포함 금지** — debug / citation
+    원문 보기 전용.
+    """
+
+    n: int  # 1-based, synthesis 프롬프트의 [n] 과 매핑
+    chunk_id: int | None
+    doc_id: int
+    title: str | None
+    section_title: str | None
+    span_text: str  # LLM 추출 (또는 rule fallback) span, 80~300자
+    relevance: float  # LLM 0~1 (fallback 시 rerank_score 복사)
+    rerank_score: float  # raw reranker 점수
+    full_snippet: str  # 원본 800자 (debug/citation 전용, synthesis 금지)
+
+
+# ─── 프롬프트 로딩 (module 초기화 1회) ───────────────────
+try:
+    EVIDENCE_PROMPT = _load_prompt("evidence_extract.txt")
+except FileNotFoundError:
+    EVIDENCE_PROMPT = ""
+    logger.warning(
+        "evidence_extract.txt not found — evidence_service will always use rule-only fallback"
+    )
+
+
+# ─── Helper: candidates → LLM 입력 블록 ──────────────────
+
+
+def _build_numbered_candidates(
+    candidates: list["SearchResult"], query: str
+) -> tuple[str, list[str]]:
+    """LLM 프롬프트의 {numbered_candidates} 블록 + 재윈도우된 full_snippet 리스트.
+
+    Returns:
+        (block_str, full_snippets) — full_snippets[i] 는 1-based n=i+1 의 원문
+    """
+    lines: list[str] = []
+    full_snippets: list[str] = []
+    for i, c in enumerate(candidates, 1):
+        title = (c.title or "").strip()
+        raw_text = c.snippet or ""
+        full = _extract_window(raw_text, query, target_chars=CANDIDATE_SNIPPET_CHARS)
+        full_snippets.append(full)
+        lines.append(f"[{i}] title: {title} / text: {full}")
+    return "\n".join(lines), full_snippets
+
+
+# ─── Helper: span length 보정 ───────────────────────────
+
+
+def _normalize_span(span: str, full: str, query: str) -> tuple[str, bool]:
+    """span 을 SPAN_MIN_CHARS ~ SPAN_MAX_CHARS 범위로 보정.
+
+    Returns:
+        (normalized_span, was_expanded)
+        - was_expanded=True 이면 "short_span_expanded" 로그 대상
+    """
+    s = (span or "").strip()
+    expanded = False
+    if len(s) < SPAN_MIN_CHARS:
+        # soft hallucination 방어 — query 중심으로 window 재확장
+        s = _extract_window(full, query, target_chars=SPAN_ENLARGE_TARGET)
+        expanded = True
+    if len(s) > SPAN_MAX_CHARS:
+        s = s[:SPAN_MAX_CHARS]
+    return s, expanded
+
+
+# ─── Helper: doc-group ordering ─────────────────────────
+
+
+def _apply_doc_group_ordering(
+    items: list[EvidenceItem],
+    results: list["SearchResult"],
+) -> list[EvidenceItem]:
+    """검색 결과 doc 순서 유지 + doc 내부만 relevance desc + n 재부여.
+
+    answer 는 [1][2][3] 순서로 생성되고 그 순서가 문맥 흐름을 결정한다.
+    전역 relevance desc 정렬은 "doc A span1 → doc B span1 → doc A span2"
+    처럼 튀면서 읽기 이상한 답변을 만든다.
+    """
+    if not items:
+        return []
+    doc_order: dict[int, int] = {}
+    for idx, r in enumerate(results):
+        if r.id not in doc_order:
+            doc_order[r.id] = idx
+    # 정렬: (doc 순서, -relevance)
+    items.sort(
+        key=lambda it: (doc_order.get(it.doc_id, 9999), -it.relevance)
+    )
+    # n 재부여
+    for new_n, it in enumerate(items, 1):
+        it.n = new_n
+    return items
+
+
+# ─── Helper: rule-only fallback ─────────────────────────
+
+
+def _build_rule_only_evidence(
+    candidates: list["SearchResult"],
+    full_snippets: list[str],
+    query: str,
+) -> list[EvidenceItem]:
+    """LLM 실패/timeout 시 rule-only 경로.
+
+    ⚠ `full_snippet[:200]` 같은 앞자르기 금지. 반드시 `_extract_window` 로
+    query 중심 윈도우를 만든다. relevance 는 rerank_score 복사.
+    """
+    items: list[EvidenceItem] = []
+    for i, (c, full) in enumerate(zip(candidates, full_snippets), 1):
+        span = _extract_window(full, query, target_chars=200)
+        # 정규화 (보통 여기서는 SPAN_MIN_CHARS 이상이지만 안전장치)
+        span, _expanded = _normalize_span(span, full, query)
+        items.append(
+            EvidenceItem(
+                n=i,
+                chunk_id=c.chunk_id,
+                doc_id=c.id,
+                title=c.title,
+                section_title=c.section_title,
+                span_text=span,
+                relevance=float(c.rerank_score or c.score or 0.0),
+                rerank_score=float(c.rerank_score or c.score or 0.0),
+                full_snippet=full,
+            )
+        )
+    return items
+
+
+# ─── Core: extract_evidence ─────────────────────────────
+
+
+async def extract_evidence(
+    query: str,
+    results: list["SearchResult"],
+    ai_client: AIClient | None = None,
+) -> tuple[list[EvidenceItem], str | None]:
+    """reranked results → EvidenceItem 리스트.
+
+    Returns:
+        (items, skip_reason)
+        skip_reason ∈ {None, "empty_retrieval", "all_low_rerank", "fast_path",
+                       "llm_timeout_fallback_rule", "llm_error_fallback_rule",
+                       "parse_failed_fallback_rule", "all_llm_rejected"}
+        - skip_reason 이 None 이 아니어도 items 는 비어있지 않을 수 있다
+          (fallback/fast_path 경로).
+    """
+    if not results:
+        return [], "empty_retrieval"
+
+    # ── 1차 rule filter: rerank_score >= EVIDENCE_MIN_RERANK + max_per_doc ──
+    candidates: list["SearchResult"] = []
+    per_doc: dict[int, int] = {}
+    for r in results:
+        raw_score = r.rerank_score if r.rerank_score is not None else r.score
+        if raw_score is None or raw_score < EVIDENCE_MIN_RERANK:
+            continue
+        if per_doc.get(r.id, 0) >= MAX_PER_DOC:
+            continue
+        candidates.append(r)
+        per_doc[r.id] = per_doc.get(r.id, 0) + 1
+        if len(candidates) >= MAX_EVIDENCE_CANDIDATES:
+            break
+
+    if not candidates:
+        return [], "all_low_rerank"
+
+    # ── Fast-path (현재 비활성) ─────────────────────────
+    if EVIDENCE_FAST_PATH_THRESHOLD is not None:
+        # ⚠ display score 가 아니라 raw rerank_score 로 판단.
+        #    normalize_display_scores 를 거친 r.score 는 frontend 용 리스케일
+        #    값이라 distribution drift 가능. fast-path 는 reranker raw 신호가 안전.
+        top_rerank = (
+            results[0].rerank_score if results[0].rerank_score is not None else 0.0
+        )
+        if top_rerank is not None and top_rerank >= EVIDENCE_FAST_PATH_THRESHOLD:
+            _block, full_snippets = _build_numbered_candidates(candidates, query)
+            items = _build_rule_only_evidence(candidates, full_snippets, query)
+            items = _apply_doc_group_ordering(items, results)
+            logger.info(
+                "evidence fast_path query=%r candidates=%d kept=%d top_rerank=%.2f",
+                query[:80], len(candidates), len(items), top_rerank,
+            )
+            return items, "fast_path"
+
+    # ── LLM 호출 준비 ───────────────────────────────────
+    if not EVIDENCE_PROMPT:
+        # 프롬프트 미로딩 → rule-only
+        _block, full_snippets = _build_numbered_candidates(candidates, query)
+        items = _build_rule_only_evidence(candidates, full_snippets, query)
+        items = _apply_doc_group_ordering(items, results)
+        logger.warning(
+            "evidence prompt_not_loaded → rule fallback query=%r kept=%d",
+            query[:80], len(items),
+        )
+        return items, "llm_error_fallback_rule"
+
+    block, full_snippets = _build_numbered_candidates(candidates, query)
+    prompt = EVIDENCE_PROMPT.replace("{query}", query).replace(
+        "{numbered_candidates}", block
+    )
+
+    client_owned = False
+    if ai_client is None:
+        ai_client = AIClient()
+        client_owned = True
+
+    t_start = time.perf_counter()
+    raw: str | None = None
+    llm_error: str | None = None
+
+    try:
+        # ⚠ semaphore 대기는 timeout 바깥. timeout 은 실제 LLM 호출에만.
+        async with get_mlx_gate():
+            async with asyncio.timeout(LLM_TIMEOUT_MS / 1000):
+                raw = await ai_client._call_chat(ai_client.ai.primary, prompt)
+    except asyncio.TimeoutError:
+        llm_error = "timeout"
+    except Exception as exc:
+        llm_error = f"llm_error:{type(exc).__name__}"
+    finally:
+        if client_owned:
+            try:
+                await ai_client.close()
+            except Exception:
+                pass
+
+    elapsed_ms = (time.perf_counter() - t_start) * 1000
+
+    # ── LLM 실패 → rule fallback ────────────────────────
+    if llm_error is not None:
+        items = _build_rule_only_evidence(candidates, full_snippets, query)
+        items = _apply_doc_group_ordering(items, results)
+        logger.warning(
+            "evidence LLM %s → rule fallback query=%r candidates=%d kept=%d elapsed_ms=%.0f",
+            llm_error, query[:80], len(candidates), len(items), elapsed_ms,
+        )
+        return items, "llm_timeout_fallback_rule" if llm_error == "timeout" else "llm_error_fallback_rule"
+
+    parsed = parse_json_response(raw or "")
+    if not isinstance(parsed, dict) or not isinstance(parsed.get("items"), list):
+        items = _build_rule_only_evidence(candidates, full_snippets, query)
+        items = _apply_doc_group_ordering(items, results)
+        logger.warning(
+            "evidence parse_failed → rule fallback query=%r raw=%r elapsed_ms=%.0f",
+            query[:80], (raw or "")[:200], elapsed_ms,
+        )
+        return items, "parse_failed_fallback_rule"
+
+    # ── LLM 출력 파싱 ──────────────────────────────────
+    short_span_expanded = 0
+    llm_items: list[EvidenceItem] = []
+    for entry in parsed["items"]:
+        if not isinstance(entry, dict):
+            continue
+        try:
+            n_raw = int(entry.get("n", 0))
+        except (TypeError, ValueError):
+            continue
+        if n_raw < 1 or n_raw > len(candidates):
+            continue
+        try:
+            relevance = float(entry.get("relevance", 0.0) or 0.0)
+        except (TypeError, ValueError):
+            relevance = 0.0
+        if relevance < MIN_RELEVANCE_KEEP:
+            continue
+        span_raw = entry.get("span")
+        if not isinstance(span_raw, str) or not span_raw.strip():
+            continue
+
+        candidate = candidates[n_raw - 1]
+        full = full_snippets[n_raw - 1]
+        span, expanded = _normalize_span(span_raw, full, query)
+        if expanded:
+            short_span_expanded += 1
+
+        llm_items.append(
+            EvidenceItem(
+                n=n_raw,  # doc-group ordering 에서 재부여됨
+                chunk_id=candidate.chunk_id,
+                doc_id=candidate.id,
+                title=candidate.title,
+                section_title=candidate.section_title,
+                span_text=span,
+                relevance=relevance,
+                rerank_score=float(
+                    candidate.rerank_score
+                    if candidate.rerank_score is not None
+                    else (candidate.score or 0.0)
+                ),
+                full_snippet=full,
+            )
+        )
+
+    # ── LLM 이 전부 reject → rule fallback ──────────────
+    if not llm_items:
+        items = _build_rule_only_evidence(candidates, full_snippets, query)
+        items = _apply_doc_group_ordering(items, results)
+        logger.warning(
+            "evidence all_llm_rejected → rule fallback query=%r elapsed_ms=%.0f",
+            query[:80], elapsed_ms,
+        )
+        return items, "all_llm_rejected"
+
+    # ── doc-group ordering + n 재부여 ───────────────────
+    llm_items = _apply_doc_group_ordering(llm_items, results)
+
+    logger.info(
+        "evidence ok query=%r candidates=%d kept=%d short_span_expanded=%d elapsed_ms=%.0f",
+        query[:80], len(candidates), len(llm_items), short_span_expanded, elapsed_ms,
+    )
+    return llm_items, None

app/services/search/fusion_service.py

@@ -219,6 +219,62 @@ def get_strategy(name: str) -> FusionStrategy:
     return cls()
 
 
+# ─── Phase 2.3: soft filter boost ───────────────────────
+
+SOFT_FILTER_MAX_BOOST = 0.05  # plan 룰 (CRITICAL)
+# ↑ RRF score는 0.01~0.05 범위 (k=60). 상한 초과 시 기존 랭킹 왜곡.
+#   기존 RRFWithBoost의 legal article boost(0.05)와 동일 최대값 → 일관성.
+SOFT_FILTER_DOMAIN_BOOST = 0.01  # 2026-04-08 실측: 0.03은 exact_keyword -0.03 악화
+# ↑ 낮게 잡는 이유: soft_filter는 "같은 도메인 doc을 동등하게 boost" → exact match
+#   doc의 상대 우위가 손상됨. 0.01 수준이면 fusion 내부 순위 역전 확률 최소.
+
+
+def apply_soft_filter_boost(
+    results: list["SearchResult"],
+    soft_filters: dict | None,
+) -> int:
+    """Phase 2.3 — QueryAnalyzer soft_filters.domain 기반 약한 score boost.
+
+    ai_domain 정확 매칭 시 SOFT_FILTER_DOMAIN_BOOST(0.01) 1회 가산.
+    document_type 매칭은 v0.1 평가셋에서 효과 측정 불가 + false positive 많음 → 제외.
+
+    Args:
+        results: fusion 직후 SearchResult 리스트 (in-place 수정)
+        soft_filters: query_analysis.soft_filters = {"domain": [...]}
+
+    Returns:
+        int — boost 적용된 결과 개수 (debug/notes용)
+    """
+    if not soft_filters:
+        return 0
+    domain_list = [str(d).lower() for d in soft_filters.get("domain", []) or []]
+    if not domain_list:
+        return 0
+
+    boosted_count = 0
+    for r in results:
+        if not r.ai_domain:
+            continue
+        ai_dom_lower = r.ai_domain.lower()
+        # 정확 매칭 또는 subdirectory 매칭 ("Industrial_Safety/Legislation" → "industrial_safety" 매칭)
+        matched = False
+        for d in domain_list:
+            if d == ai_dom_lower:
+                matched = True
+                break
+            # path 레벨 매칭: "industrial_safety/legislation" in "industrial_safety/legislation/act"
+            if d in ai_dom_lower and "/" in d:
+                matched = True
+                break
+        if matched:
+            r.score += min(SOFT_FILTER_DOMAIN_BOOST, SOFT_FILTER_MAX_BOOST)
+            boosted_count += 1
+
+    # boost 적용 후 재정렬
+    results.sort(key=lambda x: x.score, reverse=True)
+    return boosted_count
+
+
 # ─── display score 정규화 ────────────────────────────────
 
 

app/services/search/llm_gate.py

@@ -0,0 +1,58 @@
+"""MLX single-inference 전역 gate (Phase 3.1.1).
+
+Mac mini MLX primary(gemma-4-26b-a4b-it-8bit)는 **single-inference**다.
+동시 호출이 들어오면 queue가 폭발한다(실측: 23 concurrent 요청 → 22개 15초 timeout).
+
+이 모듈은 analyzer / evidence / synthesis 등 **모든 MLX-bound LLM 호출**이
+공유하는 `asyncio.Semaphore(1)`를 제공한다. MLX를 호출하는 경로는 예외 없이
+`async with get_mlx_gate():` 블록 안에서만 `AIClient._call_chat(ai.primary, ...)`
+를 호출해야 한다.
+
+## 영구 룰
+
+- **MLX primary 호출 경로는 예외 없이 gate 획득 필수**. query_analyzer /
+  evidence_service / synthesis_service 세 곳이 현재 사용자. 이후 경로가 늘어도
+  동일 gate를 import해서 사용한다. 새 Semaphore를 만들지 말 것 (큐 분할 시
+  동시 실행 발생).
+- **`asyncio.timeout(...)`은 gate 안쪽에서만 적용**. gate 대기 자체에 timeout을
+  걸면 "대기만으로 timeout 발동" 버그가 재발한다(query_analyzer 초기 이슈).
+- **fallback(Ollama) 경로는 gate 제외**. GPU Ollama는 concurrent OK. 단 현재
+  구현상 `AIClient._call_chat` 내부에서 primary→fallback 전환이 일어나므로
+  fallback도 gate 점유 상태로 실행된다. 허용 가능(fallback 빈도 낮음).
+- **MLX concurrency는 `MLX_CONCURRENCY = 1` 고정**. 모델이 바뀌어도 single-
+  inference 특성이 깨지지 않는 한 이 값을 올리지 말 것.
+
+## 확장 여지 (지금은 구현하지 않음)
+
+트래픽 증가 시 "우선순위 역전"(/ask가 analyzer background task 뒤에 밀림)이
+문제가 되면 `asyncio.PriorityQueue` 기반 우선순위 큐로 교체 가능. Gate 자체
+분리(get_analyzer_gate / get_ask_gate)는 single-inference에서 throughput
+개선이 없으므로 의미 없음.
+"""
+
+from __future__ import annotations
+
+import asyncio
+
+# MLX primary는 single-inference → 1
+MLX_CONCURRENCY = 1
+
+# 첫 호출 시 현재 event loop에 바인딩된 Semaphore 생성 (lazy init)
+_mlx_gate: asyncio.Semaphore | None = None
+
+
+def get_mlx_gate() -> asyncio.Semaphore:
+    """MLX primary 호출 경로 공용 gate. 최초 호출 시 lazy init.
+
+    사용 예:
+        async with get_mlx_gate():
+            async with asyncio.timeout(LLM_TIMEOUT_MS / 1000):
+                raw = await ai_client._call_chat(ai_client.ai.primary, prompt)
+
+    ⚠ `asyncio.timeout`은 반드시 gate 안쪽에 둘 것. 바깥에 두면 gate 대기만으로
+    timeout이 발동한다.
+    """
+    global _mlx_gate
+    if _mlx_gate is None:
+        _mlx_gate = asyncio.Semaphore(MLX_CONCURRENCY)
+    return _mlx_gate

app/services/search/query_analyzer.py

@@ -1,5 +1,443 @@
-"""Query analyzer — 자연어 쿼리 분석 (Phase 2).
+"""Query analyzer — 자연어 쿼리 분석 (Phase 2.1, async-only 구조).
 
-domain_hint, intent, hard/soft filter, normalized_queries 등 추출.
-구현은 Phase 2에서 채움.
+**핵심 철학** (memory `feedback_analyzer_async_only.md`):
+> QueryAnalyzer는 "즉시 실행하는 기능"이 아니라 "미리 준비해두는 기능"이다.
+
+Retrieval 경로에서 analyzer를 **동기 호출 금지**.
+동기 호출 가능한 API는 prewarm 전용.
+
+## Pipeline
+
+```
+query → retrieval (항상 즉시)
+         ↘ trigger_background_analysis (fire-and-forget)
+            → analyze() [5초+] → cache 저장
+
+다음 호출 (동일 쿼리) → get_cached() 히트 → Phase 2 파이프라인 활성화
+```
+
+## 룰 (plan 영구)
+  - `LLM_TIMEOUT_MS = 5000` (background 이므로 여유 OK)
+  - `MAX_NORMALIZED_QUERIES = 3` (multilingual explosion 방지)
+  - weight 합 = 1.0 정규화 필수 (fusion 왜곡 방지)
+  - 실패/저신뢰(< 0.5) 결과는 캐시 금지 (잘못된 분석 고정 방지)
+  - `analyzer_confidence` default `float 0.0` 강제 (None 금지)
+  - analyze() 동기 호출 금지. retrieval 경로는 `get_cached()` + `trigger_background_analysis()` 만 사용.
 """
+
+from __future__ import annotations
+
+import asyncio
+import hashlib
+import time
+from typing import Any
+
+from ai.client import AIClient, _load_prompt, parse_json_response
+from core.config import settings
+from core.utils import setup_logger
+
+from .llm_gate import get_mlx_gate
+
+logger = setup_logger("query_analyzer")
+
+# ─── 상수 (plan 영구 룰) ────────────────────────────────
+PROMPT_VERSION = "v2"  # prompts/query_analyze.txt 축소판
+CACHE_TTL = 86400  # 24h
+CACHE_MAXSIZE = 1000
+LLM_TIMEOUT_MS = 15000  # async 구조 (background), 동기 경로 금지
+# ↑ 실측: gemma-4-26b-a4b-it-8bit MLX, 축소 프롬프트(prompt_tok=802) 7~11초.
+#   generation이 dominant (max_tokens 무효, 자연 EOS ~289 tok 생성).
+#   background 실행이라 15초도 안전. 상향 필요 시 여기서만 조정.
+LLM_CONCURRENCY = 1  # MLX는 single-inference, 동시 호출 시 queue 폭발.
+# ↑ 실측: 23 concurrent 요청 → 22개 15초 timeout. semaphore로 순차 강제.
+#   prewarm/background/동기 호출 모두 이 semaphore 경유.
+MIN_CACHE_CONFIDENCE = 0.5  # 이 미만은 캐시 금지
+MAX_NORMALIZED_QUERIES = 3
+
+
+def _model_version() -> str:
+    """현재 primary 모델 ID를 캐시 키에 반영."""
+    if settings.ai and settings.ai.primary:
+        return settings.ai.primary.model
+    return "unknown-model"
+
+
+# ─── in-memory LRU (FIFO 근사) ──────────────────────────
+_CACHE: dict[str, dict[str, Any]] = {}
+
+# background task 참조 유지 (premature GC 방지)
+_PENDING: set[asyncio.Task[Any]] = set()
+# 동일 쿼리 중복 실행 방지 (진행 중인 쿼리 집합)
+_INFLIGHT: set[str] = set()
+
+
+def _get_llm_semaphore() -> asyncio.Semaphore:
+    """MLX single-inference gate를 반환. Phase 3.1부터 llm_gate.get_mlx_gate()
+    로 위임 — analyzer / evidence / synthesis 가 동일 semaphore 공유.
+
+    `LLM_CONCURRENCY` 상수는 하위 호환/문서용으로 유지하되, 실제 bound는
+    `llm_gate.MLX_CONCURRENCY` 가 담당한다.
+    """
+    return get_mlx_gate()
+
+
+def _cache_key(query: str) -> str:
+    raw = f"{query}|{PROMPT_VERSION}|{_model_version()}"
+    return hashlib.sha256(raw.encode("utf-8")).hexdigest()
+
+
+def get_cached(query: str) -> dict | None:
+    """TTL 경과 entry는 자동 삭제. 없으면 None.
+
+    retrieval 경로에서 cache hit 판단용으로 호출. 호출 자체는 O(1).
+    """
+    key = _cache_key(query)
+    entry = _CACHE.get(key)
+    if not entry:
+        return None
+    if time.time() - entry["ts"] > CACHE_TTL:
+        _CACHE.pop(key, None)
+        return None
+    return entry["value"]
+
+
+def set_cached(query: str, value: dict) -> None:
+    """저신뢰(< 0.5) / 빈 값은 캐시 금지. 상한 초과 시 FIFO eviction."""
+    if not value:
+        return
+    try:
+        conf = float(value.get("analyzer_confidence", 0.0) or 0.0)
+    except (TypeError, ValueError):
+        conf = 0.0
+    if conf < MIN_CACHE_CONFIDENCE:
+        return
+    key = _cache_key(query)
+    if key in _CACHE:
+        _CACHE[key] = {"value": value, "ts": time.time()}
+        return
+    if len(_CACHE) >= CACHE_MAXSIZE:
+        try:
+            oldest = next(iter(_CACHE))
+            _CACHE.pop(oldest, None)
+        except StopIteration:
+            pass
+    _CACHE[key] = {"value": value, "ts": time.time()}
+
+
+def cache_stats() -> dict[str, int]:
+    """debug/운영용 — 현재 캐시 크기 + inflight 수."""
+    return {
+        "size": len(_CACHE),
+        "maxsize": CACHE_MAXSIZE,
+        "inflight": len(_INFLIGHT),
+        "pending_tasks": len(_PENDING),
+    }
+
+
+# ─── weight 정규화 (fusion 왜곡 방지) ───────────────────
+def _normalize_weights(analysis: dict) -> dict:
+    """normalized_queries를 MAX_NORMALIZED_QUERIES로 자르고 weight 합=1.0 정규화."""
+    queries = analysis.get("normalized_queries")
+    if not isinstance(queries, list) or not queries:
+        return analysis
+
+    sanitized: list[dict] = []
+    for q in queries[:MAX_NORMALIZED_QUERIES]:
+        if not isinstance(q, dict):
+            continue
+        lang = str(q.get("lang", "")).strip() or "ko"
+        text = str(q.get("text", "")).strip()
+        if not text:
+            continue
+        try:
+            w = float(q.get("weight", 1.0))
+            if w < 0:
+                w = 0.0
+        except (TypeError, ValueError):
+            w = 1.0
+        sanitized.append({"lang": lang, "text": text, "weight": w})
+
+    if not sanitized:
+        return analysis
+
+    total = sum(q["weight"] for q in sanitized)
+    if total <= 0:
+        equal = 1.0 / len(sanitized)
+        for q in sanitized:
+            q["weight"] = equal
+    else:
+        for q in sanitized:
+            q["weight"] /= total
+
+    analysis["normalized_queries"] = sanitized
+    return analysis
+
+
+# ─── 프롬프트 로딩 (module 초기화 1회) ──────────────────
+try:
+    ANALYZE_PROMPT = _load_prompt("query_analyze.txt")
+except FileNotFoundError:
+    ANALYZE_PROMPT = ""
+    logger.warning("query_analyze.txt not found — analyzer will always return fallback")
+
+
+# ─── 기본 fallback 응답 (None 금지) ─────────────────────
+def _fallback(reason: str | None = None) -> dict:
+    """LLM 실패/timeout/parse 실패 시 반환. analyzer_confidence는 반드시 float 0.0."""
+    result: dict[str, Any] = {
+        "intent": "semantic_search",
+        "query_type": "keyword",
+        "domain_hint": "mixed",
+        "language_scope": "limited",
+        "keywords": [],
+        "must_terms": [],
+        "optional_terms": [],
+        "hard_filters": {},
+        "soft_filters": {"domain": [], "document_type": []},
+        "normalized_queries": [],
+        "expanded_terms": [],
+        "synonyms": {},
+        "analyzer_confidence": 0.0,
+    }
+    if reason:
+        result["_fallback_reason"] = reason
+    return result
+
+
+# ─── 메인 LLM 호출 (내부 사용) ──────────────────────────
+async def analyze(query: str, ai_client: AIClient | None = None) -> dict:
+    """쿼리 분석 결과 반환. 실패 시 analyzer_confidence=0.0 fallback.
+
+    **⚠️ 동기 검색 경로에서 직접 호출 금지**. 용도:
+      - `trigger_background_analysis` 내부 호출
+      - `prewarm_analyzer` startup 호출
+      - 디버깅/테스트
+
+    Args:
+        query: 사용자 쿼리 원문
+        ai_client: AIClient 인스턴스 (없으면 생성 후 자동 close)
+
+    Returns:
+        dict — 최소 `analyzer_confidence` 키는 항상 float로 존재.
+    """
+    if not query or not query.strip():
+        return _fallback("empty_query")
+
+    if not ANALYZE_PROMPT:
+        return _fallback("prompt_not_loaded")
+
+    # cache hit 즉시 반환 (prewarm 재호출 방지)
+    cached = get_cached(query)
+    if cached is not None:
+        return cached
+
+    client_owned = False
+    if ai_client is None:
+        ai_client = AIClient()
+        client_owned = True
+
+    t_start = time.perf_counter()
+    semaphore = _get_llm_semaphore()
+    # ⚠️ 중요: semaphore 대기는 timeout 포함되면 안됨 (대기만 해도 timeout 발동)
+    #   timeout은 실제 LLM 호출 구간에만 적용.
+    try:
+        async with semaphore:
+            async with asyncio.timeout(LLM_TIMEOUT_MS / 1000):
+                raw = await ai_client._call_chat(
+                    ai_client.ai.primary,
+                    ANALYZE_PROMPT.replace("{query}", query),
+                )
+    except asyncio.TimeoutError:
+        elapsed = (time.perf_counter() - t_start) * 1000
+        logger.warning(
+            "query_analyze timeout query=%r elapsed_ms=%.0f (LLM_TIMEOUT_MS=%d)",
+            query[:80],
+            elapsed,
+            LLM_TIMEOUT_MS,
+        )
+        return _fallback("timeout")
+    except Exception as exc:
+        elapsed = (time.perf_counter() - t_start) * 1000
+        logger.warning(
+            "query_analyze LLM error query=%r elapsed_ms=%.0f err=%r",
+            query[:80],
+            elapsed,
+            exc,
+        )
+        return _fallback(f"llm_error:{type(exc).__name__}")
+    finally:
+        if client_owned:
+            try:
+                await ai_client.close()
+            except Exception:
+                pass
+
+    elapsed_ms = (time.perf_counter() - t_start) * 1000
+
+    parsed = parse_json_response(raw)
+    if not isinstance(parsed, dict):
+        logger.warning(
+            "query_analyze parse failed query=%r elapsed_ms=%.0f raw=%r",
+            query[:80],
+            elapsed_ms,
+            (raw or "")[:200],
+        )
+        return _fallback("parse_failed")
+
+    try:
+        conf = float(parsed.get("analyzer_confidence", 0.0) or 0.0)
+    except (TypeError, ValueError):
+        conf = 0.0
+    parsed["analyzer_confidence"] = conf
+    parsed = _normalize_weights(parsed)
+
+    logger.info(
+        "query_analyze ok query=%r conf=%.2f intent=%s domain=%s elapsed_ms=%.0f",
+        query[:80],
+        conf,
+        parsed.get("intent"),
+        parsed.get("domain_hint"),
+        elapsed_ms,
+    )
+
+    set_cached(query, parsed)
+    return parsed
+
+
+# ─── Background trigger (retrieval 경로에서 사용) ───────
+async def _background_analyze(query: str) -> None:
+    """Background task wrapper — inflight 집합 관리 + 예외 삼킴."""
+    try:
+        await analyze(query)
+    except Exception as exc:
+        logger.warning("background analyze crashed query=%r err=%r", query[:80], exc)
+    finally:
+        _INFLIGHT.discard(query)
+
+
+def trigger_background_analysis(query: str) -> bool:
+    """retrieval 경로에서 호출. cache miss 시 background task 생성.
+
+    - 동기 함수. 즉시 반환.
+    - 이미 inflight 또는 cache hit이면 아무 작업 X, False 반환.
+    - 새 task 생성 시 True 반환.
+
+    Returns:
+        bool — task 실제로 생성되었는지 여부
+    """
+    if not query or not query.strip():
+        return False
+    if query in _INFLIGHT:
+        return False
+    if get_cached(query) is not None:
+        return False
+
+    try:
+        loop = asyncio.get_running_loop()
+    except RuntimeError:
+        logger.warning("trigger_background_analysis called outside event loop")
+        return False
+
+    _INFLIGHT.add(query)
+    task = loop.create_task(_background_analyze(query))
+    _PENDING.add(task)
+    task.add_done_callback(_PENDING.discard)
+    return True
+
+
+# ─── Prewarm (app startup) ──────────────────────────────
+# 운영에서 자주 발생하는 쿼리 샘플. 통계 기반으로 확장 예정.
+DEFAULT_PREWARM_QUERIES: list[str] = [
+    # fixed 7 (Phase 2 평가셋 core)
+    "산업안전보건법 제6장",
+    "기계 사고 관련 법령",
+    "AI 산업 동향",
+    "Python async best practice",
+    "유해화학물질을 다루는 회사가 지켜야 할 안전 의무",
+    "recent AI safety news from Europe",
+    "이세상에 존재하지 않는 문서명",
+    # 법령 관련
+    "산업안전보건법 시행령",
+    "화학물질관리법",
+    "위험성평가 절차",
+    # 뉴스 관련
+    "EU AI Act",
+    "한국 AI 산업",
+    # 실무
+    "안전보건 교육 자료",
+    "사고 조사 보고서",
+    "MSDS 작성 방법",
+]
+
+
+async def prewarm_analyzer(
+    queries: list[str] | None = None,
+    delay_between: float = 0.2,
+) -> dict[str, Any]:
+    """app startup에서 호출. 대표 쿼리를 미리 분석해 cache에 적재.
+
+    Non-blocking으로 사용: `asyncio.create_task(prewarm_analyzer())`.
+
+    Args:
+        queries: 분석할 쿼리 리스트. None이면 DEFAULT_PREWARM_QUERIES 사용.
+        delay_between: 각 쿼리 간 대기 시간 (MLX 부하 완화).
+
+    Returns:
+        dict — {queries_total, success, failed, elapsed_ms, cache_size_after}
+    """
+    if not ANALYZE_PROMPT:
+        logger.warning("prewarm skipped — prompt not loaded")
+        return {"status": "skipped", "reason": "prompt_not_loaded"}
+
+    targets = queries if queries is not None else DEFAULT_PREWARM_QUERIES
+    total = len(targets)
+    success = 0
+    failed = 0
+    t_start = time.perf_counter()
+
+    logger.info("prewarm_analyzer start queries=%d timeout_ms=%d", total, LLM_TIMEOUT_MS)
+
+    client = AIClient()
+    try:
+        for i, q in enumerate(targets, 1):
+            if get_cached(q) is not None:
+                logger.info("prewarm skip (already cached) [%d/%d] %r", i, total, q[:40])
+                success += 1
+                continue
+            result = await analyze(q, ai_client=client)
+            conf = float(result.get("analyzer_confidence", 0.0) or 0.0)
+            if conf >= MIN_CACHE_CONFIDENCE:
+                success += 1
+                logger.info("prewarm ok [%d/%d] conf=%.2f q=%r", i, total, conf, q[:40])
+            else:
+                failed += 1
+                reason = result.get("_fallback_reason", "low_conf")
+                logger.warning(
+                    "prewarm fail [%d/%d] reason=%s q=%r", i, total, reason, q[:40]
+                )
+            if delay_between > 0 and i < total:
+                await asyncio.sleep(delay_between)
+    finally:
+        try:
+            await client.close()
+        except Exception:
+            pass
+
+    elapsed_ms = (time.perf_counter() - t_start) * 1000
+    stats = cache_stats()
+    logger.info(
+        "prewarm_analyzer done total=%d success=%d failed=%d elapsed_ms=%.0f cache_size=%d",
+        total,
+        success,
+        failed,
+        elapsed_ms,
+        stats["size"],
+    )
+    return {
+        "status": "complete",
+        "queries_total": total,
+        "success": success,
+        "failed": failed,
+        "elapsed_ms": elapsed_ms,
+        "cache_size_after": stats["size"],
+    }

app/services/search/rerank_service.py

@@ -134,7 +134,12 @@ async def rerank_chunks(
             if idx is None or sc is None or idx >= len(candidates):
                 continue
             chunk = candidates[idx]
-            chunk.score = float(sc)
+            score = float(sc)
+            chunk.score = score
+            # Phase 3.1: reranker raw 점수를 별도 필드에 보존.
+            # normalize_display_scores가 나중에 .score를 랭크 기반으로 덮어써도
+            # fast-path 판단에 쓸 수 있는 원본 신호 유지.
+            chunk.rerank_score = score
             chunk.match_reason = (chunk.match_reason or "") + "+rerank"
             reranked.append(chunk)
         return reranked[:limit]

app/services/search/retrieval_service.py

@@ -1,4 +1,4 @@
-"""검색 후보 수집 서비스 (Phase 1.2).
+"""검색 후보 수집 서비스 (Phase 1.2 + Phase 2.2 multilingual).
 
 text(documents FTS + trigram) + vector(documents.embedding + chunks.embedding hybrid) 후보를
 SearchResult 리스트로 반환.
@@ -10,27 +10,80 @@ Phase 1.2-G: doc + chunks hybrid retrieval 보강.
   - documents.embedding (recall robust, 자연어 매칭 강함)
   - document_chunks.embedding (precision, segment 매칭)
   - 두 SQL 동시 호출 후 doc_id 기준 merge (chunk 가중치 1.2, doc 1.0)
+
+Phase 2.2 추가:
+  - _QUERY_EMBED_CACHE: bge-m3 query embedding 캐시 (모듈 레벨 LRU, TTL 24h)
+  - search_vector_multilingual: normalized_queries (lang별 쿼리) 배열 지원
+    QueryAnalyzer cache hit + analyzer_tier >= merge 일 때만 호출.
+  - crosslingual_ko_en NDCG 0.53 → 0.65+ 목표
 """
 
 from __future__ import annotations
 
 import asyncio
-from typing import TYPE_CHECKING
+import hashlib
+import time
+from typing import TYPE_CHECKING, Any
 
 from sqlalchemy import text
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
 
 from ai.client import AIClient
 from core.database import engine
+from core.utils import setup_logger
 
 if TYPE_CHECKING:
     from api.search import SearchResult
 
 
+logger = setup_logger("retrieval_service")
+
 # Hybrid merge 가중치 (1.2-G)
 DOC_VECTOR_WEIGHT = 1.0
 CHUNK_VECTOR_WEIGHT = 1.2
 
+# ─── Phase 2.2: Query embedding cache ───────────────────
+# bge-m3 호출 비용 절반 감소 (동일 normalized_query 재호출 방지)
+_QUERY_EMBED_CACHE: dict[str, dict[str, Any]] = {}
+QUERY_EMBED_TTL = 86400  # 24h
+QUERY_EMBED_MAXSIZE = 500
+
+
+def _query_embed_key(text_: str) -> str:
+    return hashlib.sha256(f"{text_}|bge-m3".encode("utf-8")).hexdigest()
+
+
+async def _get_query_embedding(
+    client: AIClient, text_: str
+) -> list[float] | None:
+    """Query embedding with in-memory cache.
+
+    동일 텍스트 재호출 시 bge-m3 skip. fixed query 회귀 시 vector_ms 대폭 감소.
+    """
+    if not text_:
+        return None
+    key = _query_embed_key(text_)
+    entry = _QUERY_EMBED_CACHE.get(key)
+    if entry and time.time() - entry["ts"] < QUERY_EMBED_TTL:
+        return entry["emb"]
+    try:
+        emb = await client.embed(text_)
+    except Exception as exc:
+        logger.warning("query embed failed text=%r err=%r", text_[:40], exc)
+        return None
+    if len(_QUERY_EMBED_CACHE) >= QUERY_EMBED_MAXSIZE:
+        try:
+            oldest = next(iter(_QUERY_EMBED_CACHE))
+            _QUERY_EMBED_CACHE.pop(oldest, None)
+        except StopIteration:
+            pass
+    _QUERY_EMBED_CACHE[key] = {"emb": emb, "ts": time.time()}
+    return emb
+
+
+def query_embed_cache_stats() -> dict[str, int]:
+    return {"size": len(_QUERY_EMBED_CACHE), "maxsize": QUERY_EMBED_MAXSIZE}
+
 
 async def search_text(
     session: AsyncSession, query: str, limit: int
@@ -153,11 +206,16 @@ async def search_vector(
       list[SearchResult] — doc_id 중복 제거됨. compress_chunks_to_docs는 그대로 동작.
       chunks_by_doc은 search.py에서 group_by_doc으로 보존.
     """
-    try:
     client = AIClient()
-        query_embedding = await client.embed(query)
+    try:
+        query_embedding = await _get_query_embedding(client, query)
+    finally:
+        try:
             await client.close()
         except Exception:
+            pass
+
+    if query_embedding is None:
         return []
 
     embedding_str = str(query_embedding)
@@ -307,6 +365,100 @@ def _merge_doc_and_chunk_vectors(
     return sorted(by_doc_id.values(), key=lambda r: r.score, reverse=True)
 
 
+async def search_vector_multilingual(
+    session: AsyncSession,
+    normalized_queries: list[dict],
+    limit: int,
+) -> list["SearchResult"]:
+    """Phase 2.2 — 다국어 normalized_queries 배열로 vector retrieval.
+
+    각 language query에 대해 embedding을 병렬 생성(cache hit 활용),
+    각 embedding에 대해 기존 docs+chunks hybrid 호출,
+    결과를 weight 기반으로 merge.
+
+    ⚠️ 호출 조건:
+      - QueryAnalyzer cache hit 이어야 함 (async-only 룰)
+      - analyzer_confidence 높고 normalized_queries 존재해야 함
+      - search.py에서만 호출. retrieval 경로 동기 LLM 호출 금지 룰 준수.
+
+    Args:
+        session: AsyncSession (호출자 관리, 본 함수 내부는 sessionmaker로 별도 연결 사용)
+        normalized_queries: [{"lang": "ko", "text": "...", "weight": 0.56}, ...]
+            weight는 _normalize_weights로 이미 합=1.0 정규화된 상태.
+        limit: 상위 결과 개수
+
+    Returns:
+        list[SearchResult] — doc_id 중복 제거. merged score = sum(per-query score * lang_weight).
+    """
+    if not normalized_queries:
+        return []
+
+    # 1. 각 lang별 embedding 병렬 (cache hit 활용)
+    client = AIClient()
+    try:
+        embed_tasks = [
+            _get_query_embedding(client, q["text"]) for q in normalized_queries
+        ]
+        embeddings = await asyncio.gather(*embed_tasks)
+    finally:
+        try:
+            await client.close()
+        except Exception:
+            pass
+
+    # embedding 실패한 query는 skip (weight 재정규화 없이 조용히 drop)
+    per_query_plan: list[tuple[dict, str]] = []
+    for q, emb in zip(normalized_queries, embeddings):
+        if emb is None:
+            logger.warning("multilingual embed skipped lang=%s", q.get("lang"))
+            continue
+        per_query_plan.append((q, str(emb)))
+
+    if not per_query_plan:
+        return []
+
+    # 2. 각 embedding에 대해 doc + chunks 병렬 retrieval
+    Session = async_sessionmaker(engine)
+
+    async def _one_query(q_meta: dict, embedding_str: str) -> list["SearchResult"]:
+        async def _docs() -> list["SearchResult"]:
+            async with Session() as s:
+                return await _search_vector_docs(s, embedding_str, limit * 4)
+
+        async def _chunks() -> list["SearchResult"]:
+            async with Session() as s:
+                return await _search_vector_chunks(s, embedding_str, limit * 4)
+
+        doc_r, chunk_r = await asyncio.gather(_docs(), _chunks())
+        return _merge_doc_and_chunk_vectors(doc_r, chunk_r)
+
+    per_query_results = await asyncio.gather(
+        *(_one_query(q, emb_str) for q, emb_str in per_query_plan)
+    )
+
+    # 3. weight 기반 merge — doc_id 중복 시 weighted score 합산
+    merged: dict[int, "SearchResult"] = {}
+    for (q_meta, _emb_str), results in zip(per_query_plan, per_query_results):
+        weight = float(q_meta.get("weight", 1.0) or 1.0)
+        for r in results:
+            weighted = r.score * weight
+            prev = merged.get(r.id)
+            if prev is None:
+                # 첫 방문: 원본을 shallow copy 대신 직접 wrap
+                r.score = weighted
+                r.match_reason = f"ml_{q_meta.get('lang', '?')}"
+                merged[r.id] = r
+            else:
+                # 중복: score 누적, 가장 높은 weight 소스로 match_reason 표시
+                prev.score += weighted
+                # match_reason 병합 (가독성)
+                if q_meta.get("lang") and q_meta.get("lang") not in (prev.match_reason or ""):
+                    prev.match_reason = (prev.match_reason or "ml") + f"+{q_meta['lang']}"
+
+    sorted_results = sorted(merged.values(), key=lambda r: r.score, reverse=True)
+    return sorted_results[: limit * 4]  # rerank 후보로 넉넉히
+
+
 def compress_chunks_to_docs(
     chunks: list["SearchResult"], limit: int
 ) -> tuple[list["SearchResult"], dict[int, list["SearchResult"]]]:

app/services/search/search_pipeline.py

@@ -0,0 +1,335 @@
+"""검색 파이프라인 오케스트레이션 (Phase 3.1).
+
+`/api/search/` 와 `/api/search/ask` 가 공유하는 단일 진실 소스.
+
+## 순수성 규칙 (영구)
+
+`run_search()`는 wrapper(endpoint)에서 side effect를 최대한 분리한다:
+- ❌ **금지**: `BackgroundTasks` 파라미터, `logger.info(...)` 직접 호출,
+  `record_search_event()` 호출, `SearchResponse`/`AskResponse` 직렬화
+- ✅ **허용**: `trigger_background_analysis()` (analyzer cache miss 시
+  fire-and-forget task — retrieval 전략의 일부, 자가 완결됨)
+- ✅ **허용**: retrieval / fusion / rerank / diversity / display 정규화 /
+  confidence 계산 같은 내부 서비스 호출
+
+반환값은 `PipelineResult` 하나. wrapper가 그 안에서 필요한 필드를 꺼내
+logger / telemetry / 응답 직렬화를 수행한다.
+
+## Phase 2 호환
+
+본 모듈은 기존 `app/api/search.py::search()` 함수 본문을 lift-and-shift 한
+것이다. 변수명 / notes 문자열 / timing 키 / logger 포맷 은 wrapper 쪽에서
+완전히 동일하게 재구성된다. refactor 전후 `/search?debug=true` 응답은
+byte-level 에 가깝게 일치해야 한다.
+"""
+
+from __future__ import annotations
+
+import time
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING, Literal
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from . import query_analyzer
+from .fusion_service import (
+    DEFAULT_FUSION,
+    apply_soft_filter_boost,
+    get_strategy,
+    normalize_display_scores,
+)
+from .rerank_service import (
+    MAX_CHUNKS_PER_DOC,
+    MAX_RERANK_INPUT,
+    apply_diversity,
+    rerank_chunks,
+)
+from .retrieval_service import (
+    compress_chunks_to_docs,
+    search_text,
+    search_vector,
+    search_vector_multilingual,
+)
+from services.search_telemetry import (
+    compute_confidence,
+    compute_confidence_hybrid,
+    compute_confidence_reranked,
+)
+
+if TYPE_CHECKING:
+    from api.search import SearchResult
+
+
+# ─── Phase 2.1: analyzer_confidence 3단계 게이트 ──────────
+# search.py 에서 이동. search.py 의 /search wrapper 는 이 상수들을
+# 노출할 필요 없으므로 파이프라인 모듈에만 둔다.
+ANALYZER_TIER_IGNORE = 0.5  # < 0.5 → analyzer 완전 무시, soft_filter 비활성
+ANALYZER_TIER_ORIGINAL = 0.7  # < 0.7 → original query fallback
+ANALYZER_TIER_MERGE = 0.85  # < 0.85 → original + analyzed merge
+
+
+def _analyzer_tier(confidence: float) -> str:
+    """analyzer_confidence → 사용 tier 문자열. Phase 2.2/2.3에서 실제 분기용."""
+    if confidence < ANALYZER_TIER_IGNORE:
+        return "ignore"
+    if confidence < ANALYZER_TIER_ORIGINAL:
+        return "original_fallback"
+    if confidence < ANALYZER_TIER_MERGE:
+        return "merge"
+    return "analyzed"
+
+
+# ─── 반환 타입 ─────────────────────────────────────────────
+
+
+@dataclass(slots=True)
+class PipelineResult:
+    """run_search() 반환 — wrapper 가 필요한 모든 state 를 담는다."""
+
+    # ── 최종 결과 (API 노출) ──
+    results: "list[SearchResult]"
+    mode: str
+    confidence_signal: float
+
+    # ── 중간 단계 (evidence 입력 + debug) ──
+    text_results: "list[SearchResult]"
+    vector_results: "list[SearchResult]"  # doc 압축 후
+    raw_chunks: "list[SearchResult]"  # chunk 원본 (rerank/evidence용)
+    chunks_by_doc: "dict[int, list[SearchResult]]"
+
+    # ── 쿼리 분석 메타 ──
+    query_analysis: dict | None
+    analyzer_cache_hit: bool
+    analyzer_confidence: float  # 항상 float (None 금지)
+    analyzer_tier: str
+
+    # ── 관측 ──
+    timing_ms: dict[str, float] = field(default_factory=dict)
+    notes: list[str] = field(default_factory=list)
+
+
+# ─── 메인 파이프라인 ───────────────────────────────────────
+
+
+async def run_search(
+    session: AsyncSession,
+    q: str,
+    *,
+    mode: Literal["fts", "trgm", "vector", "hybrid"] = "hybrid",
+    limit: int = 20,
+    fusion: str = DEFAULT_FUSION,
+    rerank: bool = True,
+    analyze: bool = False,
+) -> PipelineResult:
+    """검색 파이프라인 실행.
+
+    retrieval → fusion → rerank → diversity → display 정규화 → confidence 계산
+    까지 수행하고 `PipelineResult` 를 반환한다. logging / BackgroundTasks /
+    응답 직렬화는 절대 수행하지 않는다 (wrapper 책임).
+
+    Args:
+        session: AsyncSession (caller 가 관리)
+        q: 사용자 쿼리 원문
+        mode: fts | trgm | vector | hybrid
+        limit: 최종 결과 수 (hybrid 에서는 fusion 입력 후보 수는 이보다 넓음)
+        fusion: legacy | rrf | rrf_boost
+        rerank: bge-reranker-v2-m3 활성화 (hybrid 전용)
+        analyze: QueryAnalyzer 활성화 (cache hit 조건부 멀티링구얼 / soft filter)
+
+    Returns:
+        PipelineResult
+    """
+    # 로컬 import — circular 방지 (SearchResult 는 api.search 에 inline 선언)
+    from api.search import SearchResult  # noqa: F401 — TYPE_CHECKING 실런타임 반영
+
+    timing: dict[str, float] = {}
+    notes: list[str] = []
+    text_results: list["SearchResult"] = []
+    vector_results: list["SearchResult"] = []  # doc-level (압축 후, fusion 입력)
+    raw_chunks: list["SearchResult"] = []  # chunk-level (raw, Phase 1.3 reranker용)
+    chunks_by_doc: dict[int, list["SearchResult"]] = {}  # Phase 1.3 reranker용 보존
+    query_analysis: dict | None = None
+    analyzer_confidence: float = 0.0
+    analyzer_tier: str = "disabled"
+
+    t_total = time.perf_counter()
+
+    # Phase 2.1 (async 구조): QueryAnalyzer는 동기 호출 금지.
+    #   - cache hit → query_analysis 활용 (Phase 2.2/2.3 파이프라인 조건부)
+    #   - cache miss → 기존 경로 유지 + background task 트리거 (fire-and-forget)
+    # 실측(gemma-4 10초+) 기반 결정. memory: feedback_analyzer_async_only.md
+    analyzer_cache_hit: bool = False
+    if analyze:
+        query_analysis = query_analyzer.get_cached(q)
+        if query_analysis is not None:
+            analyzer_cache_hit = True
+            try:
+                analyzer_confidence = float(
+                    query_analysis.get("analyzer_confidence", 0.0) or 0.0
+                )
+            except (TypeError, ValueError):
+                analyzer_confidence = 0.0
+            analyzer_tier = _analyzer_tier(analyzer_confidence)
+            notes.append(
+                f"analyzer cache_hit conf={analyzer_confidence:.2f} tier={analyzer_tier}"
+            )
+        else:
+            # cache miss → background analyzer 트리거 (retrieval 차단 X)
+            triggered = query_analyzer.trigger_background_analysis(q)
+            analyzer_tier = "cache_miss"
+            notes.append(
+                "analyzer cache_miss"
+                + (" (bg triggered)" if triggered else " (bg inflight)")
+            )
+
+    # Phase 2.2: multilingual vector search 활성 조건 (보수적)
+    #   - cache hit + analyzer_tier == "analyzed" (≥0.85 고신뢰)
+    #   - normalized_queries 2개 이상 (lang 다양성 있음)
+    #   - domain_hint == "news" 또는 language_scope == "global"
+    #   ↑ 1차 측정 결과: document 도메인에서 multilingual이 natural_language_ko
+    #     -0.10 악화시킴. 영어 번역이 한국어 법령 검색에서 noise로 작용.
+    #     news / global 영역에서만 multilingual 활성 (news_crosslingual +0.10 개선 확인).
+    use_multilingual: bool = False
+    normalized_queries: list[dict] = []
+    if analyzer_cache_hit and analyzer_tier == "analyzed" and query_analysis:
+        domain_hint = query_analysis.get("domain_hint", "mixed")
+        language_scope = query_analysis.get("language_scope", "limited")
+        is_multilingual_candidate = (
+            domain_hint == "news" or language_scope == "global"
+        )
+        if is_multilingual_candidate:
+            raw_nq = query_analysis.get("normalized_queries") or []
+            if isinstance(raw_nq, list) and len(raw_nq) >= 2:
+                normalized_queries = [
+                    nq for nq in raw_nq if isinstance(nq, dict) and nq.get("text")
+                ]
+                if len(normalized_queries) >= 2:
+                    use_multilingual = True
+                    notes.append(
+                        f"multilingual langs={[nq.get('lang') for nq in normalized_queries]}"
+                        f" hint={domain_hint}/{language_scope}"
+                    )
+
+    if mode == "vector":
+        t0 = time.perf_counter()
+        if use_multilingual:
+            raw_chunks = await search_vector_multilingual(session, normalized_queries, limit)
+        else:
+            raw_chunks = await search_vector(session, q, limit)
+        timing["vector_ms"] = (time.perf_counter() - t0) * 1000
+        if not raw_chunks:
+            notes.append("vector_search_returned_empty (AI client error or no embeddings)")
+        # vector 단독 모드도 doc 압축해서 다양성 확보 (chunk 중복 방지)
+        vector_results, chunks_by_doc = compress_chunks_to_docs(raw_chunks, limit)
+        results = vector_results
+    else:
+        t0 = time.perf_counter()
+        text_results = await search_text(session, q, limit)
+        timing["text_ms"] = (time.perf_counter() - t0) * 1000
+
+        if mode == "hybrid":
+            t1 = time.perf_counter()
+            if use_multilingual:
+                raw_chunks = await search_vector_multilingual(session, normalized_queries, limit)
+            else:
+                raw_chunks = await search_vector(session, q, limit)
+            timing["vector_ms"] = (time.perf_counter() - t1) * 1000
+
+            # chunk-level → doc-level 압축 (raw chunks는 chunks_by_doc에 보존)
+            t1b = time.perf_counter()
+            vector_results, chunks_by_doc = compress_chunks_to_docs(raw_chunks, limit)
+            timing["compress_ms"] = (time.perf_counter() - t1b) * 1000
+
+            if not vector_results:
+                notes.append("vector_search_returned_empty — text-only fallback")
+
+            t2 = time.perf_counter()
+            strategy = get_strategy(fusion)
+            # fusion은 doc 기준 — 더 넓게 가져옴 (rerank 후보용)
+            fusion_limit = max(limit * 5, 100) if rerank else limit
+            fused_docs = strategy.fuse(text_results, vector_results, q, fusion_limit)
+            timing["fusion_ms"] = (time.perf_counter() - t2) * 1000
+            notes.append(f"fusion={strategy.name}")
+            notes.append(
+                f"chunks raw={len(raw_chunks)} compressed={len(vector_results)} "
+                f"unique_docs={len(chunks_by_doc)}"
+            )
+
+            # Phase 2.3: soft_filter boost (cache hit + tier != ignore 일 때만)
+            # analyzer_confidence < 0.5 (tier=ignore)는 비활성.
+            if (
+                analyzer_cache_hit
+                and analyzer_tier != "ignore"
+                and query_analysis
+            ):
+                soft_filters = query_analysis.get("soft_filters") or {}
+                if soft_filters:
+                    boosted = apply_soft_filter_boost(fused_docs, soft_filters)
+                    if boosted > 0:
+                        notes.append(f"soft_filter_boost applied={boosted}")
+
+            if rerank:
+                # Phase 1.3: reranker — chunk 기준 입력
+                # fusion 결과 doc_id로 chunks_by_doc에서 raw chunks 회수
+                t3 = time.perf_counter()
+                rerank_input: list["SearchResult"] = []
+                for doc in fused_docs:
+                    chunks = chunks_by_doc.get(doc.id, [])
+                    if chunks:
+                        # doc당 max 2 chunk (latency/VRAM 보호)
+                        rerank_input.extend(chunks[:MAX_CHUNKS_PER_DOC])
+                    else:
+                        # text-only 매치 doc → doc 자체를 chunk처럼 wrap
+                        rerank_input.append(doc)
+                    if len(rerank_input) >= MAX_RERANK_INPUT:
+                        break
+                rerank_input = rerank_input[:MAX_RERANK_INPUT]
+                notes.append(f"rerank input={len(rerank_input)}")
+
+                reranked = await rerank_chunks(q, rerank_input, limit * 3)
+                timing["rerank_ms"] = (time.perf_counter() - t3) * 1000
+
+                # diversity (chunk → doc 압축, max_per_doc=2, top score>0.90 unlimited)
+                t4 = time.perf_counter()
+                results = apply_diversity(reranked, max_per_doc=MAX_CHUNKS_PER_DOC)[:limit]
+                timing["diversity_ms"] = (time.perf_counter() - t4) * 1000
+            else:
+                # rerank 비활성: fused_docs를 그대로 (limit 적용)
+                results = fused_docs[:limit]
+        else:
+            results = text_results
+
+    # display score 정규화 — 프론트엔드는 score*100을 % 표시.
+    # fusion 내부 score(RRF는 0.01~0.05 범위)를 그대로 노출하면 표시가 깨짐.
+    # Phase 3.1: rerank_score 필드는 여기서 건드리지 않음 (raw 보존).
+    normalize_display_scores(results)
+
+    timing["total_ms"] = (time.perf_counter() - t_total) * 1000
+
+    # confidence는 fusion 적용 전 raw 신호로 계산 (Phase 0.5 이후 fused score는 절대값 의미 없음)
+    # rerank 활성 시 reranker score가 가장 신뢰할 수 있는 신호 → 우선 사용
+    if mode == "hybrid":
+        if rerank and "rerank_ms" in timing:
+            confidence_signal = compute_confidence_reranked(results)
+        else:
+            confidence_signal = compute_confidence_hybrid(text_results, vector_results)
+    elif mode == "vector":
+        confidence_signal = compute_confidence(vector_results, "vector")
+    else:
+        confidence_signal = compute_confidence(text_results, mode)
+
+    return PipelineResult(
+        results=results,
+        mode=mode,
+        confidence_signal=confidence_signal,
+        text_results=text_results,
+        vector_results=vector_results,
+        raw_chunks=raw_chunks,
+        chunks_by_doc=chunks_by_doc,
+        query_analysis=query_analysis,
+        analyzer_cache_hit=analyzer_cache_hit,
+        analyzer_confidence=analyzer_confidence,
+        analyzer_tier=analyzer_tier,
+        timing_ms=timing,
+        notes=notes,
+    )

app/services/search/synthesis_service.py

@@ -1,6 +1,422 @@
-"""Grounded answer synthesis 서비스 (Phase 3).
+"""Grounded answer synthesis 서비스 (Phase 3.3).
 
-evidence span을 Gemma 4에 전달해 인용 기반 답변 생성.
-3~4초 soft timeout, 타임아웃 시 결과만 반환 fallback.
-구현은 Phase 3에서 채움.
+evidence span 을 Gemma 4 에 전달해 citation 기반 답변을 생성한다.
+캐시 / timeout / citation 검증 / refused 처리 포함.
+
+## 영구 룰
+
+- **span-only 입력**: `_render_prompt()` 는 `EvidenceItem.span_text` 만 참조한다.
+  `EvidenceItem.full_snippet` 을 프롬프트에 포함하면 LLM 이 span 밖 내용을
+  hallucinate 한다. 이 규칙이 깨지면 시스템 무너짐 → docstring + 코드 패턴으로
+  방어 (함수 상단에서 제한 뷰만 만든다).
+- **cache 는 성공 + 고신뢰에만**: 실패 (timeout/parse_failed/llm_error) 와
+  low confidence / refused 는 캐시 금지. 잘못된 답변 고정 방지.
+- **MLX gate 공유**: `get_mlx_gate()` 경유. analyzer / evidence 와 동일 semaphore.
+- **timeout 15s**: `asyncio.timeout` 은 gate 안쪽에서만 적용. 바깥에 두면 gate
+  대기만으로 timeout 발동.
+- **citation 검증**: 본문 `[n]` 범위 초과는 제거 + `hallucination_flags` 기록.
+  answer 수정본을 반환하되 status 는 completed 유지 (silent fix + observable).
 """
+
+from __future__ import annotations
+
+import asyncio
+import hashlib
+import re
+import time
+from dataclasses import dataclass, field
+from typing import TYPE_CHECKING, Literal
+
+from ai.client import AIClient, _load_prompt, parse_json_response
+from core.config import settings
+from core.utils import setup_logger
+
+from .llm_gate import get_mlx_gate
+
+if TYPE_CHECKING:
+    from .evidence_service import EvidenceItem
+
+logger = setup_logger("synthesis")
+
+# ─── 상수 (plan 영구 룰) ─────────────────────────────────
+PROMPT_VERSION = "v1"
+LLM_TIMEOUT_MS = 15000
+CACHE_TTL = 3600  # 1h (answer 는 원문 변경에 민감 → query_analyzer 24h 보다 짧게)
+CACHE_MAXSIZE = 300
+MAX_ANSWER_CHARS = 400
+
+SynthesisStatus = Literal[
+    "completed",
+    "timeout",
+    "skipped",
+    "no_evidence",
+    "parse_failed",
+    "llm_error",
+]
+
+
+# ─── 반환 타입 ───────────────────────────────────────────
+
+
+@dataclass(slots=True)
+class SynthesisResult:
+    """synthesize() 반환. cache dict 에 들어가는 payload 이기도 함."""
+
+    status: SynthesisStatus
+    answer: str | None
+    used_citations: list[int]  # 검증 후 실제로 본문에 등장한 n
+    confidence: Literal["high", "medium", "low"] | None
+    refused: bool
+    refuse_reason: str | None
+    elapsed_ms: float
+    cache_hit: bool
+    hallucination_flags: list[str] = field(default_factory=list)
+    raw_preview: str | None = None  # debug=true 일 때 LLM raw 500자
+
+
+# ─── 프롬프트 로딩 (module 초기화 1회) ──────────────────
+try:
+    SYNTHESIS_PROMPT = _load_prompt("search_synthesis.txt")
+except FileNotFoundError:
+    SYNTHESIS_PROMPT = ""
+    logger.warning(
+        "search_synthesis.txt not found — synthesis will always return llm_error"
+    )
+
+
+# ─── in-memory LRU (FIFO 근사, query_analyzer 패턴 복제) ─
+_CACHE: dict[str, SynthesisResult] = {}
+
+
+def _model_version() -> str:
+    """현재 primary 모델 ID — 캐시 키에 반영."""
+    if settings.ai and settings.ai.primary:
+        return settings.ai.primary.model
+    return "unknown-model"
+
+
+def _cache_key(query: str, chunk_ids: list[int]) -> str:
+    """(query + sorted chunk_ids + PROMPT_VERSION + model) sha256."""
+    sorted_ids = ",".join(str(c) for c in sorted(chunk_ids))
+    raw = f"{query}|{sorted_ids}|{PROMPT_VERSION}|{_model_version()}"
+    return hashlib.sha256(raw.encode("utf-8")).hexdigest()
+
+
+def get_cached(query: str, chunk_ids: list[int]) -> SynthesisResult | None:
+    """캐시 조회. TTL 경과는 자동 삭제."""
+    key = _cache_key(query, chunk_ids)
+    entry = _CACHE.get(key)
+    if entry is None:
+        return None
+    # TTL 체크는 elapsed_ms 를 악용할 수 없으므로 별도 저장
+    # 여기서는 단순 policy 로 처리: entry 가 있으면 반환 (eviction 은 FIFO 시점)
+    # 정확한 TTL 이 필요하면 (ts, result) tuple 로 저장해야 함.
+    return entry
+
+
+def _should_cache(result: SynthesisResult) -> bool:
+    """실패/저신뢰/refused 는 캐시 금지."""
+    return (
+        result.status == "completed"
+        and result.confidence in ("high", "medium")
+        and not result.refused
+        and result.answer is not None
+    )
+
+
+def set_cached(query: str, chunk_ids: list[int], result: SynthesisResult) -> None:
+    """조건부 저장 + FIFO eviction."""
+    if not _should_cache(result):
+        return
+    key = _cache_key(query, chunk_ids)
+    if key in _CACHE:
+        _CACHE[key] = result
+        return
+    if len(_CACHE) >= CACHE_MAXSIZE:
+        try:
+            oldest = next(iter(_CACHE))
+            _CACHE.pop(oldest, None)
+        except StopIteration:
+            pass
+    _CACHE[key] = result
+
+
+def cache_stats() -> dict[str, int]:
+    """debug/운영용."""
+    return {"size": len(_CACHE), "maxsize": CACHE_MAXSIZE}
+
+
+# ─── Prompt rendering (🔒 span_text ONLY) ───────────────
+
+
+def _render_prompt(query: str, evidence: list["EvidenceItem"]) -> str:
+    """{query} / {numbered_evidence} 치환.
+
+    ⚠ **MUST NOT access `item.full_snippet`**. Use `span_text` ONLY.
+    Rationale: 프롬프트에 full_snippet 을 넣으면 LLM 이 span 밖 내용으로
+    hallucinate 한다. full_snippet 은 debug / citation 원문 전용.
+
+    제한 뷰만 만들어서 full_snippet 접근을 문법적으로 어렵게 만든다.
+    """
+    # 제한 뷰 — 이 튜플에는 span_text 외의 snippet 필드가 없다
+    spans: list[tuple[int, str, str]] = [
+        (i.n, (i.title or "").strip(), i.span_text) for i in evidence
+    ]
+    lines = [f"[{n}] {title}\n{span}" for n, title, span in spans]
+    numbered_block = "\n\n".join(lines)
+    return SYNTHESIS_PROMPT.replace("{query}", query).replace(
+        "{numbered_evidence}", numbered_block
+    )
+
+
+# ─── Citation 검증 ──────────────────────────────────────
+
+_CITATION_RE = re.compile(r"\[(\d+)\]")
+
+
+def _validate_citations(
+    answer: str,
+    n_max: int,
+) -> tuple[str, list[int], list[str]]:
+    """본문 `[n]` 범위 초과 제거 + used_citations 추출 + flags.
+
+    Returns:
+        (corrected_answer, used_citations, hallucination_flags)
+    """
+    flags: list[str] = []
+    seen: set[int] = set()
+    used: list[int] = []
+    corrected = answer
+
+    for match in _CITATION_RE.findall(answer):
+        try:
+            n = int(match)
+        except ValueError:
+            continue
+        if n < 1 or n > n_max:
+            # 범위 초과 → 본문에서 제거 + flag
+            corrected = corrected.replace(f"[{n}]", "")
+            flags.append(f"removed_n_{n}")
+            continue
+        if n not in seen:
+            seen.add(n)
+            used.append(n)
+
+    used.sort()
+
+    if len(corrected) > MAX_ANSWER_CHARS:
+        corrected = corrected[:MAX_ANSWER_CHARS]
+        flags.append("length_clipped")
+
+    return corrected, used, flags
+
+
+# ─── Core: synthesize ───────────────────────────────────
+
+
+async def synthesize(
+    query: str,
+    evidence: list["EvidenceItem"],
+    ai_client: AIClient | None = None,
+    debug: bool = False,
+) -> SynthesisResult:
+    """evidence → grounded answer.
+
+    Failure modes 는 모두 SynthesisResult 로 반환한다 (예외는 외부로 전파되지
+    않음). 호출자 (`/ask` wrapper) 가 status 를 보고 user-facing 메시지를
+    결정한다.
+    """
+    t_start = time.perf_counter()
+
+    # ── evidence 비면 즉시 no_evidence ─────────────────
+    if not evidence:
+        return SynthesisResult(
+            status="no_evidence",
+            answer=None,
+            used_citations=[],
+            confidence=None,
+            refused=False,
+            refuse_reason=None,
+            elapsed_ms=(time.perf_counter() - t_start) * 1000,
+            cache_hit=False,
+            hallucination_flags=[],
+            raw_preview=None,
+        )
+
+    # ── cache lookup ───────────────────────────────────
+    # chunk_id 가 None 인 text-only wrap 은 음수 doc_id 로 구분 → key 안정화
+    chunk_ids = [
+        (e.chunk_id if e.chunk_id is not None else -e.doc_id) for e in evidence
+    ]
+    cached = get_cached(query, chunk_ids)
+    if cached is not None:
+        return SynthesisResult(
+            status=cached.status,
+            answer=cached.answer,
+            used_citations=list(cached.used_citations),
+            confidence=cached.confidence,
+            refused=cached.refused,
+            refuse_reason=cached.refuse_reason,
+            elapsed_ms=(time.perf_counter() - t_start) * 1000,
+            cache_hit=True,
+            hallucination_flags=list(cached.hallucination_flags),
+            raw_preview=cached.raw_preview if debug else None,
+        )
+
+    # ── prompt 준비 ─────────────────────────────────────
+    if not SYNTHESIS_PROMPT:
+        return SynthesisResult(
+            status="llm_error",
+            answer=None,
+            used_citations=[],
+            confidence=None,
+            refused=False,
+            refuse_reason=None,
+            elapsed_ms=(time.perf_counter() - t_start) * 1000,
+            cache_hit=False,
+            hallucination_flags=["prompt_not_loaded"],
+            raw_preview=None,
+        )
+
+    prompt = _render_prompt(query, evidence)
+    prompt_preview = prompt[:500] if debug else None
+
+    # ── LLM 호출 ───────────────────────────────────────
+    client_owned = False
+    if ai_client is None:
+        ai_client = AIClient()
+        client_owned = True
+
+    raw: str | None = None
+    llm_error: str | None = None
+
+    try:
+        async with get_mlx_gate():
+            async with asyncio.timeout(LLM_TIMEOUT_MS / 1000):
+                raw = await ai_client._call_chat(ai_client.ai.primary, prompt)
+    except asyncio.TimeoutError:
+        llm_error = "timeout"
+    except Exception as exc:
+        llm_error = f"llm_error:{type(exc).__name__}"
+    finally:
+        if client_owned:
+            try:
+                await ai_client.close()
+            except Exception:
+                pass
+
+    elapsed_ms = (time.perf_counter() - t_start) * 1000
+
+    if llm_error is not None:
+        status: SynthesisStatus = "timeout" if llm_error == "timeout" else "llm_error"
+        logger.warning(
+            "synthesis %s query=%r evidence_n=%d elapsed_ms=%.0f",
+            llm_error, query[:80], len(evidence), elapsed_ms,
+        )
+        return SynthesisResult(
+            status=status,
+            answer=None,
+            used_citations=[],
+            confidence=None,
+            refused=False,
+            refuse_reason=None,
+            elapsed_ms=elapsed_ms,
+            cache_hit=False,
+            hallucination_flags=[llm_error],
+            raw_preview=None,
+        )
+
+    parsed = parse_json_response(raw or "")
+    if not isinstance(parsed, dict):
+        logger.warning(
+            "synthesis parse_failed query=%r raw=%r elapsed_ms=%.0f",
+            query[:80], (raw or "")[:200], elapsed_ms,
+        )
+        return SynthesisResult(
+            status="parse_failed",
+            answer=None,
+            used_citations=[],
+            confidence=None,
+            refused=False,
+            refuse_reason=None,
+            elapsed_ms=elapsed_ms,
+            cache_hit=False,
+            hallucination_flags=["parse_failed"],
+            raw_preview=(raw or "")[:500] if debug else None,
+        )
+
+    # ── JSON 필드 검증 ──────────────────────────────────
+    answer_raw = parsed.get("answer", "")
+    if not isinstance(answer_raw, str):
+        answer_raw = ""
+
+    conf_raw = parsed.get("confidence", "low")
+    if conf_raw not in ("high", "medium", "low"):
+        conf_raw = "low"
+
+    refused_raw = bool(parsed.get("refused", False))
+    refuse_reason_raw = parsed.get("refuse_reason")
+    if refuse_reason_raw is not None and not isinstance(refuse_reason_raw, str):
+        refuse_reason_raw = None
+
+    # refused 면 answer 무시 + citations 비움
+    if refused_raw:
+        result = SynthesisResult(
+            status="completed",
+            answer=None,
+            used_citations=[],
+            confidence=conf_raw,  # type: ignore[arg-type]
+            refused=True,
+            refuse_reason=refuse_reason_raw,
+            elapsed_ms=elapsed_ms,
+            cache_hit=False,
+            hallucination_flags=[],
+            raw_preview=(raw or "")[:500] if debug else None,
+        )
+        logger.info(
+            "synthesis refused query=%r evidence_n=%d conf=%s elapsed_ms=%.0f reason=%r",
+            query[:80], len(evidence), conf_raw, elapsed_ms, (refuse_reason_raw or "")[:80],
+        )
+        # refused 는 캐시 금지 (_should_cache)
+        return result
+
+    # ── citation 검증 ───────────────────────────────────
+    corrected_answer, used_citations, flags = _validate_citations(
+        answer_raw, n_max=len(evidence)
+    )
+
+    # answer 가 공백만 남으면 low confidence 로 강등
+    if not corrected_answer.strip():
+        corrected_answer_final: str | None = None
+        conf_raw = "low"
+        flags.append("empty_after_validation")
+    else:
+        corrected_answer_final = corrected_answer
+
+    result = SynthesisResult(
+        status="completed",
+        answer=corrected_answer_final,
+        used_citations=used_citations,
+        confidence=conf_raw,  # type: ignore[arg-type]
+        refused=False,
+        refuse_reason=None,
+        elapsed_ms=elapsed_ms,
+        cache_hit=False,
+        hallucination_flags=flags,
+        raw_preview=(raw or "")[:500] if debug else None,
+    )
+
+    logger.info(
+        "synthesis ok query=%r evidence_n=%d answer_len=%d citations=%d conf=%s flags=%s elapsed_ms=%.0f",
+        query[:80],
+        len(evidence),
+        len(corrected_answer_final or ""),
+        len(used_citations),
+        conf_raw,
+        ",".join(flags) if flags else "-",
+        elapsed_ms,
+    )
+
+    # 조건부 캐시 저장
+    set_cached(query, chunk_ids, result)
+    return result

app/services/search_telemetry.py

@@ -244,6 +244,7 @@ async def record_search_event(
     results: list[Any],
     mode: str,
     confidence: float | None = None,
+    analyzer_confidence: float | None = None,
 ) -> None:
     """검색 응답 직후 호출. 실패 트리거에 해당하면 로그 INSERT.
 
@@ -253,6 +254,13 @@ async def record_search_event(
     confidence 파라미터:
       - None이면 results 기준으로 자체 계산 (legacy 호출용).
       - 명시적으로 전달되면 그 값 사용 (Phase 0.5+: fusion 적용 전 raw 신호 기준).
+
+    analyzer_confidence (Phase 2.1):
+      - QueryAnalyzer의 쿼리 분석 신뢰도 (result confidence와 다른 축).
+      - `result.confidence` 가 낮더라도 `analyzer_confidence` 가 높으면
+        "retrieval failure" (corpus에 정답 없음)로 해석 가능.
+      - 반대로 analyzer_confidence < 0.5 이면 "query understanding failure" 해석.
+      - Phase 2.1에서는 context에만 기록 (failure_reason 분류는 Phase 2.2+에서).
     """
     if user_id is None:
         return
@@ -260,7 +268,10 @@ async def record_search_event(
     if confidence is None:
         confidence = compute_confidence(results, mode)
     result_count = len(results)
-    base_ctx = _build_context(results, mode, extra={"confidence": confidence})
+    extra_ctx: dict[str, Any] = {"confidence": confidence}
+    if analyzer_confidence is not None:
+        extra_ctx["analyzer_confidence"] = float(analyzer_confidence)
+    base_ctx = _build_context(results, mode, extra=extra_ctx)
 
     # ── 1) reformulation 체크 (이전 쿼리가 있으면 그걸 로깅) ──
     prior = await _record_and_get_prior(user_id, query)

app/workers/digest_worker.py

@@ -0,0 +1,44 @@
+"""Phase 4: Global Digest 워커.
+
+7일 뉴스를 country × topic 으로 묶어 cluster-level LLM 요약을 생성하고
+global_digests / digest_topics 테이블에 저장한다.
+
+- APScheduler cron (매일 04:00 KST) + 수동 호출 공용 진입점
+- PIPELINE_HARD_CAP = 600초 hard cap 으로 cron stuck 절대 방지
+- 단독 실행: `python -m workers.digest_worker`
+"""
+
+import asyncio
+
+from core.utils import setup_logger
+from services.digest.pipeline import run_digest_pipeline
+
+logger = setup_logger("digest_worker")
+
+PIPELINE_HARD_CAP = 600  # 10분 hard cap
+
+
+async def run() -> None:
+    """APScheduler + 수동 호출 공용 진입점.
+
+    pipeline 자체는 timeout 으로 감싸지 않음 (per-call timeout 은 summarizer 가 처리).
+    여기서는 전체 hard cap 만 강제.
+    """
+    try:
+        result = await asyncio.wait_for(
+            run_digest_pipeline(),
+            timeout=PIPELINE_HARD_CAP,
+        )
+        logger.info(f"[global_digest] 워커 완료: {result}")
+    except asyncio.TimeoutError:
+        logger.error(
+            f"[global_digest] HARD CAP {PIPELINE_HARD_CAP}s 초과 — 워커 강제 중단. "
+            f"기존 digest 는 commit 시점에만 갱신되므로 그대로 유지됨. "
+            f"다음 cron 실행에서 재시도."
+        )
+    except Exception as e:
+        logger.exception(f"[global_digest] 워커 실패: {e}")
+
+
+if __name__ == "__main__":
+    asyncio.run(run())

app/workers/embed_worker.py

@@ -1,4 +1,19 @@
-"""벡터 임베딩 워커 — GPU 서버 bge-m3 호출"""
+"""벡터 임베딩 워커 — GPU 서버 bge-m3 호출 (doc-level recall vector)
+
+## 구조 원칙 (영구)
+
+doc-level embedding 은 "요약 벡터" (recall 담당). chunk-level embedding (chunk_worker)
+이 precision 을 담당하는 hybrid 구조 (`retrieval_service._search_vector_docs` 참조).
+
+**본문 일부를 임베딩 입력으로 쓰면 안 된다**. 500k자 교재의 앞 6000자는 표지+목차 —
+임베딩 품질이 쓰레기가 된다. 대신 AI 가 이미 생성한 `ai_summary` 를 중심으로 한
+metadata (title + summary + tags) 를 입력으로 사용한다.
+
+이 선택의 이점:
+- 입력 길이 ~1500자 이하 → Ollama 기본 context 안전 (num_ctx 조정 불필요)
+- AI 요약은 "전체 문서의 압축 의미" → doc-level 역할에 정확히 부합
+- 태그는 상위 semantic signal → noise 없음
+"""
 
 from datetime import datetime, timezone
 
@@ -10,27 +25,59 @@ from models.document import Document
 
 logger = setup_logger("embed_worker")
 
-# 임베딩용 텍스트 최대 길이 (bge-m3: 8192 토큰)
-MAX_EMBED_TEXT = 6000
+# ─── 품질 가드 상수 ──────────────────────────────────
+MIN_SUMMARY_CHARS = 50       # 너무 짧은 요약은 저품질 — 본문 fallback 사용
+MAX_TAGS = 5                 # 상위 N개만 (과도한 태그는 임베딩 노이즈)
+FALLBACK_PREFIX_CHARS = 800  # ai_summary 누락/저품질 시 본문 프리픽스
+
 EMBED_MODEL_VERSION = "bge-m3"
 
 
+def _build_embed_input(doc: Document) -> str:
+    """doc-level recall vector 용 metadata 입력 빌더.
+
+    Returns:
+        임베딩 모델에 보낼 문자열. 평균 ~500~1500자.
+
+    품질 가드:
+    - ai_summary 가 MIN_SUMMARY_CHARS 미만이면 저품질로 보고 본문 fallback
+    - tags 는 상위 MAX_TAGS 개만 (과도한 태그는 임베딩에 노이즈)
+    - ai_domain 은 현 단계에서 제외 (taxonomy 품질이 안정화될 때까지)
+    """
+    parts = [f"제목: {(doc.title or '').strip()}"]
+
+    summary = (doc.ai_summary or "").strip()
+    use_summary = len(summary) >= MIN_SUMMARY_CHARS
+    if use_summary:
+        parts.append(f"요약: {summary}")
+
+    # tags: 리스트면 상위 MAX_TAGS, 문자열이면 그대로 (이상 케이스)
+    if doc.ai_tags:
+        if isinstance(doc.ai_tags, list):
+            tags_list = [str(t).strip() for t in doc.ai_tags[:MAX_TAGS] if t]
+            tags_str = ", ".join(tags_list)
+        else:
+            tags_str = str(doc.ai_tags)
+        if tags_str:
+            parts.append(f"키워드: {tags_str}")
+
+    # ai_summary 품질 미달 시 본문 프리픽스 fallback (최소 recall 확보)
+    if not use_summary and doc.extracted_text:
+        parts.append(f"본문: {doc.extracted_text[:FALLBACK_PREFIX_CHARS]}")
+
+    return "\n".join(p for p in parts if p).strip()
+
+
 async def process(document_id: int, session: AsyncSession) -> None:
-    """문서 벡터 임베딩 생성"""
+    """문서 벡터 임베딩 생성 (doc-level recall vector)"""
     doc = await session.get(Document, document_id)
     if not doc:
         raise ValueError(f"문서 ID {document_id}를 찾을 수 없음")
 
-    if not doc.extracted_text:
-        raise ValueError(f"문서 ID {document_id}: extracted_text가 비어있음")
-
-    # title + 본문 앞부분을 결합하여 임베딩 입력 생성
-    title_part = doc.title or ""
-    text_part = doc.extracted_text[:MAX_EMBED_TEXT]
-    embed_input = f"{title_part}\n\n{text_part}".strip()
+    embed_input = _build_embed_input(doc)
 
     if not embed_input:
-        logger.warning(f"[임베딩] document_id={document_id}: 빈 텍스트, 스킵")
+        logger.warning(f"[임베딩] document_id={document_id}: 빈 입력, 스킵")
         return
 
     client = AIClient()
@@ -39,6 +86,9 @@ async def process(document_id: int, session: AsyncSession) -> None:
         doc.embedding = vector
         doc.embed_model_version = EMBED_MODEL_VERSION
         doc.embedded_at = datetime.now(timezone.utc)
-        logger.info(f"[임베딩] document_id={document_id}: {len(vector)}차원 벡터 생성")
+        logger.info(
+            f"[임베딩] document_id={document_id}: {len(vector)}차원 벡터 "
+            f"(input_len={len(embed_input)}, has_summary={bool(doc.ai_summary)})"
+        )
     finally:
         await client.close()

app/workers/extract_worker.py

@@ -39,7 +39,8 @@ async def process(document_id: int, session: AsyncSession) -> None:
         if not full_path.exists():
             raise FileNotFoundError(f"파일 없음: {full_path}")
         text = full_path.read_text(encoding="utf-8", errors="replace")
-        doc.extracted_text = text
+        # NUL 바이트 제거 (Postgres TEXT 저장 시 CharacterNotInRepertoireError 방지)
+        doc.extracted_text = text.replace("\x00", "")
         doc.extracted_at = datetime.now(timezone.utc)
         doc.extractor_version = "direct_read"
         logger.info(f"[텍스트] {doc.file_path} ({len(text)}자)")
@@ -70,7 +71,8 @@ async def process(document_id: int, session: AsyncSession) -> None:
         resp.raise_for_status()
 
         data = resp.json()
-        doc.extracted_text = data.get("markdown", "")
+        # NUL 바이트 제거 (Postgres TEXT 저장 시 CharacterNotInRepertoireError 방지)
+        doc.extracted_text = data.get("markdown", "").replace("\x00", "")
         doc.extracted_at = datetime.now(timezone.utc)
         doc.extractor_version = EXTRACTOR_VERSION
         logger.info(f"[kordoc] {doc.file_path} ({len(doc.extracted_text)}자)")
@@ -106,7 +108,8 @@ async def process(document_id: int, session: AsyncSession) -> None:
             out_file = tmp_dir / f"input_{document_id}.{out_ext}"
             if out_file.exists():
                 text = out_file.read_text(encoding="utf-8", errors="replace")
-                doc.extracted_text = text[:15000]
+                # NUL 바이트 제거 (Postgres TEXT 저장 시 CharacterNotInRepertoireError 방지)
+                doc.extracted_text = text.replace("\x00", "")[:15000]
                 doc.extracted_at = datetime.now(timezone.utc)
                 doc.extractor_version = "libreoffice"
                 out_file.unlink()

app/workers/queue_consumer.py

@@ -133,7 +133,9 @@ async def consume_queue():
                     if not item:
                         logger.warning(f"[{stage}] queue_id={queue_id} 없음 (삭제됨?), skip")
                         continue
-                    item.error_message = str(e)[:500]
+                    # 빈 메시지 방어: str → repr → 클래스명 순 fallback
+                    err_text = str(e) or repr(e) or type(e).__name__
+                    item.error_message = err_text[:500]
                     if item.attempts >= item.max_attempts:
                         item.status = "failed"
                         logger.error(f"[{stage}] document_id={document_id} 영구 실패: {e}")

config.yaml

@@ -6,8 +6,8 @@ ai:
 
   models:
     primary:
-      endpoint: "http://100.76.254.116:8800/v1/chat/completions"
-      model: "mlx-community/Qwen3.5-35B-A3B-4bit"
+      endpoint: "http://100.76.254.116:8801/v1/chat/completions"
+      model: "mlx-community/gemma-4-26b-a4b-it-8bit"
       max_tokens: 4096
       timeout: 60
 

docker-compose.yml

@@ -89,6 +89,7 @@ services:
       - ./config.yaml:/app/config.yaml:ro
       - ./scripts:/app/scripts:ro
       - ./logs:/app/logs
+      - ./migrations:/app/migrations:ro
     depends_on:
       postgres:
         condition: service_healthy

frontend/src/lib/components/UploadDropzone.svelte

@@ -6,6 +6,11 @@
 
   let { onupload = () => {} } = $props();
 
+  // home-caddy `request_body max_size 100MB` (infra_inventory.md D8 / Cloudflare 섹션 참조).
+  // 100MB 초과 파일은 NAS PKM 폴더 직접 마운트 → file_watcher 5분 간격 자동 인덱싱 경로 사용.
+  const MAX_UPLOAD_BYTES = 100 * 1024 * 1024;
+  const NAS_FALLBACK_HINT = '대용량 파일은 NAS의 PKM 폴더에 직접 두면 file_watcher 가 5분 이내에 자동 인덱싱합니다.';
+
   let dragging = $state(false);
   let uploading = $state(false);
   let uploadFiles = $state([]);
@@ -56,7 +61,24 @@
   });
 
   async function handleFiles(fileList) {
-    const files = Array.from(fileList || []);
+    const allFiles = Array.from(fileList || []);
+    if (allFiles.length === 0) return;
+
+    // 사전 크기 검사 — 100MB 초과는 즉시 차단 + NAS file_watcher 안내
+    const tooLarge = allFiles.filter(f => f.size > MAX_UPLOAD_BYTES);
+    const files = allFiles.filter(f => f.size <= MAX_UPLOAD_BYTES);
+
+    if (tooLarge.length > 0) {
+      const names = tooLarge
+        .map(f => `${f.name} (${(f.size / 1024 / 1024).toFixed(1)}MB)`)
+        .join(', ');
+      addToast(
+        'error',
+        `100MB 초과 파일은 업로드 불가 (${tooLarge.length}건: ${names}). ${NAS_FALLBACK_HINT}`,
+        10000
+      );
+    }
+
     if (files.length === 0) return;
 
     uploading = true;
@@ -78,6 +100,14 @@
       } catch (err) {
         uploadFiles[i].status = 'failed';
         failed++;
+        // 서버 측 413 (사전 검사 통과했지만 인프라 한도에 걸린 경우)
+        if (err && err.status === 413) {
+          addToast(
+            'error',
+            `${files[i].name}: 서버 거절 (Payload Too Large). ${NAS_FALLBACK_HINT}`,
+            10000
+          );
+        }
       }
       uploadFiles = [...uploadFiles];
     }

frontend/src/lib/components/ask/AskAnswer.svelte

@@ -0,0 +1,144 @@
+<!--
+  AskAnswer.svelte — /ask 페이지 상단 패널.
+
+  Answer 본문 + clickable [n] citations + 신뢰도/상태 Badge.
+  status != completed 또는 refused=true → warning empty state +
+  no_results_reason + "검색 결과 확인하기" 역링크.
+-->
+<script lang="ts">
+  import Badge from '$lib/components/ui/Badge.svelte';
+  import Button from '$lib/components/ui/Button.svelte';
+  import EmptyState from '$lib/components/ui/EmptyState.svelte';
+  import Skeleton from '$lib/components/ui/Skeleton.svelte';
+  import { AlertTriangle, Sparkles } from 'lucide-svelte';
+  import type { AskResponse, Confidence, SynthesisStatus } from '$lib/types/ask';
+
+  interface Props {
+    data: AskResponse | null;
+    loading: boolean;
+    onCitationClick: (n: number) => void;
+  }
+
+  let { data, loading, onCitationClick }: Props = $props();
+
+  type Token =
+    | { type: 'text'; value: string }
+    | { type: 'cite'; n: number; raw: string };
+
+  function splitAnswer(text: string): Token[] {
+    return text
+      .split(/(\[\d+\])/g)
+      .filter(Boolean)
+      .map((tok): Token => {
+        const m = tok.match(/^\[(\d+)\]$/);
+        return m
+          ? { type: 'cite', n: Number(m[1]), raw: tok }
+          : { type: 'text', value: tok };
+      });
+  }
+
+  function confidenceTone(
+    c: Confidence | null,
+  ): 'success' | 'warning' | 'error' | 'neutral' {
+    if (c === 'high') return 'success';
+    if (c === 'medium') return 'warning';
+    if (c === 'low') return 'error';
+    return 'neutral';
+  }
+
+  function confidenceLabel(c: Confidence | null): string {
+    if (c === 'high') return '높음';
+    if (c === 'medium') return '중간';
+    if (c === 'low') return '낮음';
+    return '없음';
+  }
+
+  const STATUS_LABEL: Record<SynthesisStatus, string> = {
+    completed: '답변 완료',
+    timeout: '답변 지연',
+    skipped: '답변 생략',
+    no_evidence: '근거 없음',
+    parse_failed: '형식 오류',
+    llm_error: 'AI 오류',
+  };
+
+  let tokens = $derived(data?.ai_answer ? splitAnswer(data.ai_answer) : []);
+  let showAnswer = $derived(
+    !!data && !!data.ai_answer && data.synthesis_status === 'completed' && !data.refused,
+  );
+  let showWarning = $derived(!!data && !showAnswer);
+</script>
+
+<section class="bg-surface border border-default rounded-card p-5">
+  <!-- 헤더 -->
+  <div class="flex items-start justify-between gap-3 mb-4">
+    <div>
+      <p class="text-[10px] font-semibold tracking-wider uppercase text-dim flex items-center gap-1.5">
+        <Sparkles size={12} /> AI Answer
+      </p>
+      <h2 class="mt-1 text-base font-semibold text-text">근거 기반 답변</h2>
+    </div>
+
+    {#if data && !loading}
+      <div class="flex flex-wrap gap-1.5">
+        <Badge tone={confidenceTone(data.confidence)} size="sm">
+          신뢰도 {confidenceLabel(data.confidence)}
+        </Badge>
+        <Badge tone="neutral" size="sm">
+          {STATUS_LABEL[data.synthesis_status]}
+        </Badge>
+        {#if data.synthesis_ms > 0}
+          <Badge tone="neutral" size="sm">
+            {Math.round(data.synthesis_ms)}ms
+          </Badge>
+        {/if}
+      </div>
+    {/if}
+  </div>
+
+  <!-- 본문 -->
+  {#if loading}
+    <div class="space-y-3">
+      <Skeleton w="w-3/4" h="h-4" />
+      <Skeleton w="w-full" h="h-4" />
+      <Skeleton w="w-5/6" h="h-4" />
+      <p class="mt-4 text-xs text-dim flex items-center gap-2">
+        <span class="inline-block w-3 h-3 rounded-full border-2 border-dim border-t-accent animate-spin"></span>
+        근거 기반 답변 생성 중… 약 15초 소요
+      </p>
+    </div>
+  {:else if showAnswer && data}
+    <div class="text-sm leading-7 text-text">
+      {#each tokens as tok}
+        {#if tok.type === 'cite'}
+          <button
+            type="button"
+            class="inline-block align-baseline text-accent font-semibold hover:underline focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-accent-ring rounded px-0.5"
+            onclick={() => onCitationClick(tok.n)}
+            aria-label={`인용 ${tok.n}번 보기`}
+          >
+            {tok.raw}
+          </button>
+        {:else}
+          <span>{tok.value}</span>
+        {/if}
+      {/each}
+    </div>
+  {:else if showWarning && data}
+    <EmptyState
+      icon={AlertTriangle}
+      title={data.refused && data.no_results_reason
+        ? data.no_results_reason
+        : (data.no_results_reason ?? '관련 근거를 찾지 못했습니다.')}
+      description="검색 결과를 직접 확인해 보세요."
+    >
+      <Button
+        variant="secondary"
+        size="sm"
+        href={`/documents?q=${encodeURIComponent(data.query)}`}
+      >
+        검색 결과 확인하기
+      </Button>
+    </EmptyState>
+  {/if}
+</section>

frontend/src/lib/components/ask/AskEvidence.svelte

@@ -0,0 +1,91 @@
+<!--
+  AskEvidence.svelte — /ask 페이지 우측 sticky 패널.
+
+  ⚠ 영구 룰 (Phase 3.4 plan):
+    `citation.full_snippet` 은 UI 에 직접 렌더 금지. debug 모드(`?debug=1`)
+    에서 hover tooltip 으로만 조건부 노출 가능.
+
+    이 규칙이 깨지면 backend span-precision UX 가치가 사라진다. 코드 리뷰에서
+    반드시 reject. span_text 만 본문으로 노출한다.
+-->
+<script lang="ts">
+  import Badge from '$lib/components/ui/Badge.svelte';
+  import EmptyState from '$lib/components/ui/EmptyState.svelte';
+  import Skeleton from '$lib/components/ui/Skeleton.svelte';
+  import { BookOpen } from 'lucide-svelte';
+  import type { AskResponse } from '$lib/types/ask';
+
+  interface Props {
+    data: AskResponse | null;
+    loading: boolean;
+    activeCitation: number | null;
+    registerCitation: (n: number, node: HTMLElement) => { destroy: () => void };
+  }
+
+  let { data, loading, activeCitation, registerCitation }: Props = $props();
+
+  let citations = $derived(data?.citations ?? []);
+</script>
+
+<section class="bg-surface border border-default rounded-card p-5">
+  <div class="flex items-start justify-between gap-3 mb-4">
+    <div>
+      <p class="text-[10px] font-semibold tracking-wider uppercase text-dim flex items-center gap-1.5">
+        <BookOpen size={12} /> Evidence Highlights
+      </p>
+      <h3 class="mt-1 text-sm font-semibold text-text">인용 근거</h3>
+    </div>
+    {#if data && !loading}
+      <Badge tone="neutral" size="sm">{citations.length}개</Badge>
+    {/if}
+  </div>
+
+  {#if loading}
+    <div class="space-y-3">
+      {#each Array(2) as _}
+        <div class="border border-default rounded-card p-4 space-y-2">
+          <Skeleton w="w-24" h="h-3" />
+          <Skeleton w="w-full" h="h-3" />
+          <Skeleton w="w-5/6" h="h-3" />
+          <Skeleton w="w-3/4" h="h-3" />
+        </div>
+      {/each}
+    </div>
+  {:else if citations.length === 0}
+    <EmptyState title="표시할 근거가 없습니다." class="py-6" />
+  {:else}
+    <div class="space-y-3">
+      {#each citations as citation (citation.n)}
+        {@const isActive = activeCitation === citation.n}
+        <article
+          class="border rounded-card p-4 transition-colors {isActive
+            ? 'border-accent ring-2 ring-accent/20 bg-accent/5'
+            : 'border-default'}"
+          use:registerCitation={citation.n}
+        >
+          <div class="flex items-start gap-2">
+            <span class="text-accent font-bold text-sm shrink-0">[{citation.n}]</span>
+            <div class="flex-1 min-w-0">
+              <strong class="block text-sm text-text truncate">
+                {citation.title ?? `문서 ${citation.doc_id}`}
+              </strong>
+              {#if citation.section_title}
+                <p class="mt-0.5 text-xs text-dim truncate">{citation.section_title}</p>
+              {/if}
+            </div>
+          </div>
+
+          <!-- ⚠ span_text 만 렌더. full_snippet 금지 -->
+          <p class="mt-3 text-sm leading-relaxed text-text whitespace-pre-wrap">
+            {citation.span_text}
+          </p>
+
+          <div class="mt-3 flex gap-2 text-[10px] text-dim">
+            <span>relevance {citation.relevance.toFixed(2)}</span>
+            <span>rerank {citation.rerank_score.toFixed(2)}</span>
+          </div>
+        </article>
+      {/each}
+    </div>
+  {/if}
+</section>

frontend/src/lib/components/ask/AskResults.svelte

@@ -0,0 +1,78 @@
+<!--
+  AskResults.svelte — /ask 페이지 하단 패널.
+
+  검색 결과 리스트. DocumentCard 재사용 X — SearchResult 필드 셋이 달라서
+  의존성 리스크 회피. inline 간단 카드로 title/score/snippet/section_title 표시.
+  클릭 시 `/documents/{id}` 로 이동.
+-->
+<script lang="ts">
+  import Badge from '$lib/components/ui/Badge.svelte';
+  import EmptyState from '$lib/components/ui/EmptyState.svelte';
+  import Skeleton from '$lib/components/ui/Skeleton.svelte';
+  import { FileText } from 'lucide-svelte';
+  import type { AskResponse } from '$lib/types/ask';
+
+  interface Props {
+    data: AskResponse | null;
+    loading: boolean;
+  }
+
+  let { data, loading }: Props = $props();
+
+  let results = $derived(data?.results ?? []);
+</script>
+
+<section class="bg-surface border border-default rounded-card p-5">
+  <div class="flex items-start justify-between gap-3 mb-4">
+    <div>
+      <p class="text-[10px] font-semibold tracking-wider uppercase text-dim flex items-center gap-1.5">
+        <FileText size={12} /> Search Results
+      </p>
+      <h3 class="mt-1 text-sm font-semibold text-text">검색 결과</h3>
+    </div>
+    {#if data && !loading}
+      <Badge tone="neutral" size="sm">{data.total}개</Badge>
+    {/if}
+  </div>
+
+  {#if loading}
+    <div class="space-y-3">
+      {#each Array(5) as _}
+        <div class="border border-default rounded-card p-4 space-y-2">
+          <Skeleton w="w-2/3" h="h-4" />
+          <Skeleton w="w-full" h="h-3" />
+          <Skeleton w="w-4/5" h="h-3" />
+        </div>
+      {/each}
+    </div>
+  {:else if results.length === 0}
+    <EmptyState title="검색 결과가 없습니다." class="py-6" />
+  {:else}
+    <div class="space-y-3">
+      {#each results as result (result.id)}
+        <a
+          href={`/documents/${result.id}`}
+          class="block border border-default rounded-card p-4 hover:border-accent hover:bg-surface-hover transition-colors"
+        >
+          <div class="flex items-start justify-between gap-3">
+            <strong class="text-sm text-text flex-1 min-w-0 truncate">
+              {result.title ?? `문서 ${result.id}`}
+            </strong>
+            <div class="flex gap-1.5 text-[10px] text-dim shrink-0">
+              <span>score {result.score.toFixed(2)}</span>
+              {#if result.rerank_score != null}
+                <span>rerank {result.rerank_score.toFixed(2)}</span>
+              {/if}
+            </div>
+          </div>
+          {#if result.section_title}
+            <p class="mt-1 text-xs text-dim truncate">{result.section_title}</p>
+          {/if}
+          {#if result.snippet}
+            <p class="mt-2 text-xs text-dim line-clamp-2">{result.snippet}</p>
+          {/if}
+        </a>
+      {/each}
+    </div>
+  {/if}
+</section>

frontend/src/lib/types/ask.ts

@@ -0,0 +1,64 @@
+/**
+ * Phase 3.4: `/api/search/ask` 응답 타입.
+ *
+ * Backend Pydantic 모델 (`app/api/search.py::AskResponse`) 과 1:1 매칭.
+ * 필드 변경 시 양쪽 동시 수정 필수.
+ */
+
+export type SynthesisStatus =
+  | 'completed'
+  | 'timeout'
+  | 'skipped'
+  | 'no_evidence'
+  | 'parse_failed'
+  | 'llm_error';
+
+export type Confidence = 'high' | 'medium' | 'low';
+
+export interface Citation {
+  n: number;
+  chunk_id: number | null;
+  doc_id: number;
+  title: string | null;
+  section_title: string | null;
+  /** LLM이 추출한 50~300자 핵심 span. UI에서 이것만 노출. */
+  span_text: string;
+  /**
+   * 원본 800자 window.
+   *
+   * ⚠ UI 기본 경로에서 절대 렌더 금지. debug 모드에서 hover tooltip 용도로만
+   * 조건부 노출 가능. full_snippet을 보여주면 backend span-precision UX
+   * 가치가 사라진다 (plan §Evidence 표시 규칙).
+   */
+  full_snippet: string;
+  relevance: number;
+  rerank_score: number;
+}
+
+export interface SearchResult {
+  id: number;
+  title: string | null;
+  ai_domain: string | null;
+  ai_summary: string | null;
+  file_format: string;
+  score: number;
+  snippet: string | null;
+  match_reason: string | null;
+  chunk_id: number | null;
+  chunk_index: number | null;
+  section_title: string | null;
+  rerank_score: number | null;
+}
+
+export interface AskResponse {
+  results: SearchResult[];
+  ai_answer: string | null;
+  citations: Citation[];
+  synthesis_status: SynthesisStatus;
+  synthesis_ms: number;
+  confidence: Confidence | null;
+  refused: boolean;
+  no_results_reason: string | null;
+  query: string;
+  total: number;
+}

frontend/src/routes/+layout.svelte

@@ -80,6 +80,7 @@
           <SystemStatusDot />
         </div>
         <div class="flex items-center gap-1">
+          <Button variant="ghost" size="sm" href="/ask">질문</Button>
           <Button variant="ghost" size="sm" href="/news">뉴스</Button>
           <Button variant="ghost" size="sm" href="/inbox">Inbox</Button>
           <Button variant="ghost" size="sm" href="/settings">설정</Button>

frontend/src/routes/ask/+page.svelte

@@ -0,0 +1,150 @@
+<!--
+  /ask — Phase 3.4 Ask Pipeline Frontend.
+
+  URL-driven: `/ask?q=<encoded>` 가 진입점. $effect 로 q 변화 감지 →
+  `/api/search/ask` 호출 → 3-panel 렌더 (Answer / Evidence / Results).
+
+  중복 호출 방지: lastQuery 가드 (hydration + reactive trigger 시 같은 q 2번 발동 방지).
+-->
+<script lang="ts">
+  import { page } from '$app/stores';
+  import { goto } from '$app/navigation';
+  import { api, type ApiError } from '$lib/api';
+  import { addToast } from '$lib/stores/toast';
+  import EmptyState from '$lib/components/ui/EmptyState.svelte';
+  import AskAnswer from '$lib/components/ask/AskAnswer.svelte';
+  import AskEvidence from '$lib/components/ask/AskEvidence.svelte';
+  import AskResults from '$lib/components/ask/AskResults.svelte';
+  import { Sparkles, Search } from 'lucide-svelte';
+  import type { AskResponse } from '$lib/types/ask';
+
+  // ── state ───────────────────────────────────────────
+  let queryInput = $state('');
+  let data = $state<AskResponse | null>(null);
+  let loading = $state(false);
+
+  // 중복 호출 방지 가드 (hydration + reactive trigger 이중 발동 방지)
+  let lastQuery = '';
+
+  // citation scroll 연동: Answer 가 [n] 클릭 → Evidence 카드로 이동 + highlight
+  const citationNodes = new Map<number, HTMLElement>();
+  let activeCitation = $state<number | null>(null);
+
+  function registerCitation(n: number, node: HTMLElement) {
+    citationNodes.set(n, node);
+    return {
+      destroy() {
+        citationNodes.delete(n);
+      },
+    };
+  }
+
+  function scrollToCitation(n: number) {
+    activeCitation = n;
+    const node = citationNodes.get(n);
+    node?.scrollIntoView({ behavior: 'smooth', block: 'center' });
+  }
+
+  // ── submit (URL-driven, back 자동) ──────────────────
+  function submit() {
+    const q = queryInput.trim();
+    if (!q) return;
+    goto(`/ask?q=${encodeURIComponent(q)}`);
+  }
+
+  function handleKeydown(e: KeyboardEvent) {
+    if (e.key === 'Enter' && !e.isComposing) {
+      e.preventDefault();
+      submit();
+    }
+  }
+
+  // ── API 호출 ───────────────────────────────────────
+  async function runAsk(q: string) {
+    loading = true;
+    activeCitation = null;
+    try {
+      data = await api<AskResponse>(
+        `/search/ask?q=${encodeURIComponent(q)}&limit=10`,
+      );
+    } catch (err) {
+      const apiErr = err as ApiError;
+      addToast('error', apiErr.detail || '답변 생성 실패');
+      data = null;
+    } finally {
+      loading = false;
+    }
+  }
+
+  // ── URL → runAsk (중복 가드) ────────────────────────
+  $effect(() => {
+    const q = $page.url.searchParams.get('q') ?? '';
+    queryInput = q;
+    if (!q) {
+      data = null;
+      loading = false;
+      lastQuery = '';
+      return;
+    }
+    if (q === lastQuery) return;
+    lastQuery = q;
+    runAsk(q);
+  });
+</script>
+
+<svelte:head>
+  <title>질문 - PKM</title>
+</svelte:head>
+
+<div class="h-full overflow-auto">
+  <!-- 상단 검색바 (sticky) -->
+  <div class="sticky top-0 z-10 bg-bg/80 backdrop-blur border-b border-default px-4 py-3">
+    <div class="flex items-center gap-2 max-w-5xl mx-auto">
+      <div class="relative flex-1">
+        <Search
+          size={14}
+          class="absolute left-3 top-1/2 -translate-y-1/2 text-dim pointer-events-none"
+        />
+        <input
+          data-search-input
+          type="text"
+          bind:value={queryInput}
+          onkeydown={handleKeydown}
+          placeholder="질문을 입력하세요 (/ 키로 포커스)"
+          class="w-full pl-9 pr-3 py-2 bg-surface border border-default rounded-lg text-text text-sm focus:border-accent outline-none"
+        />
+      </div>
+    </div>
+  </div>
+
+  <!-- 본문 -->
+  <div class="max-w-5xl mx-auto p-4">
+    {#if !queryInput && !loading && !data}
+      <div class="py-16">
+        <EmptyState
+          icon={Sparkles}
+          title="근거 기반 답변을 받아보세요"
+          description="질문을 입력하면 문서에서 근거를 찾아 인용 기반 답변을 생성합니다."
+        />
+      </div>
+    {:else}
+      <div class="grid gap-4 lg:grid-cols-[1.2fr_0.9fr] items-start">
+        <!-- 좌: Answer + Results -->
+        <div class="flex flex-col gap-4 min-w-0">
+          <AskAnswer {data} {loading} onCitationClick={scrollToCitation} />
+          <AskResults {data} {loading} />
+        </div>
+
+        <!-- 우: Evidence (lg 이상 sticky) -->
+        <div class="lg:sticky lg:top-20 lg:self-start min-w-0">
+          <AskEvidence
+            {data}
+            {loading}
+            {activeCitation}
+            {registerCitation}
+          />
+        </div>
+      </div>
+    {/if}
+  </div>
+</div>

frontend/src/routes/documents/+page.svelte

@@ -3,7 +3,7 @@
   import { goto } from '$app/navigation';
   import { api } from '$lib/api';
   import { addToast } from '$lib/stores/toast';
-  import { Info, List, LayoutGrid, ChevronLeft, X, Plus, Trash2, Tag, FolderTree, Rows3, Rows2 } from 'lucide-svelte';
+  import { Info, List, LayoutGrid, ChevronLeft, X, Plus, Trash2, Tag, FolderTree, Rows3, Rows2, Sparkles } from 'lucide-svelte';
   import DocumentCard from '$lib/components/DocumentCard.svelte';
   import DocumentTable from '$lib/components/DocumentTable.svelte';
   import DocumentViewer from '$lib/components/DocumentViewer.svelte';
@@ -441,6 +441,15 @@
         <option value="trgm">부분매칭</option>
         <option value="vector">의미검색</option>
       </select>
+      {#if searchQuery.trim()}
+        <a
+          href={`/ask?q=${encodeURIComponent(searchQuery.trim())}`}
+          class="flex items-center gap-1 px-2.5 py-1.5 rounded-lg border border-default text-dim hover:text-accent hover:border-accent transition-colors text-xs"
+          title="이 쿼리로 AI 답변 보기"
+        >
+          <Sparkles size={14} /> AI 답변
+        </a>
+      {/if}
       <button
         onclick={toggleViewMode}
         class="p-1.5 rounded-lg border border-default text-dim hover:text-accent hover:border-accent transition-colors"

frontend/src/routes/inbox/+page.svelte

@@ -59,9 +59,9 @@
   async function loadInbox() {
     loading = true;
     try {
-      // TODO(backend): /documents/?review_status=pending 서버 필터 지원 시 page_size 축소
-      const data = await api('/documents/?page_size=200');
-      documents = (data.items || []).filter((d) => d.review_status === 'pending');
+      // 서버 필터 review_status=pending 적용 — page_size 100 이내 안전
+      const data = await api('/documents/?review_status=pending&page_size=100');
+      documents = data.items || [];
     } catch (err) {
       addToast('error', 'Inbox 로딩 실패');
     } finally {

migrations/101_global_digests.sql

@@ -0,0 +1,57 @@
+-- Phase 4 Global News Digest
+-- 7일 rolling window 뉴스를 country × topic 2-level로 묶어 매일 새벽 4시 KST 배치 생성
+-- 검색 파이프라인 미사용. documents → clustering → cluster-level LLM summarization → digest
+-- 사용자 결정: country→topic 2-level, cluster-level LLM only, drop 금지 fallback,
+--             adaptive threshold, EMA centroid, time-decay (λ=ln(2)/3 ≈ 0.231)
+
+-- 부모 테이블: 하루 단위 digest run 메타데이터
+CREATE TABLE global_digests (
+    id              BIGSERIAL PRIMARY KEY,
+    digest_date     DATE NOT NULL,                    -- KST 기준 생성일
+    window_start    TIMESTAMPTZ NOT NULL,             -- rolling window 시작 (UTC)
+    window_end      TIMESTAMPTZ NOT NULL,             -- 생성 시점 (UTC)
+    decay_lambda    DOUBLE PRECISION NOT NULL,        -- 실제 사용된 time-decay λ
+
+    total_articles  INTEGER NOT NULL DEFAULT 0,
+    total_countries INTEGER NOT NULL DEFAULT 0,
+    total_topics    INTEGER NOT NULL DEFAULT 0,
+
+    generation_ms   INTEGER,                          -- 워커 실행 시간 (성능 회귀 감지)
+    llm_calls       INTEGER NOT NULL DEFAULT 0,
+    llm_failures    INTEGER NOT NULL DEFAULT 0,       -- = fallback 사용 횟수
+    status          VARCHAR(20) NOT NULL DEFAULT 'success',  -- success | partial | failed
+
+    created_at      TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+
+    UNIQUE (digest_date)   -- idempotency: 같은 날짜 재실행 시 DELETE+INSERT
+);
+
+CREATE INDEX idx_global_digests_date ON global_digests (digest_date DESC);
+
+-- 자식 테이블: country × topic 단위
+CREATE TABLE digest_topics (
+    id                BIGSERIAL PRIMARY KEY,
+    digest_id         BIGINT NOT NULL REFERENCES global_digests(id) ON DELETE CASCADE,
+
+    country           VARCHAR(10) NOT NULL,           -- KR | US | JP | CN | FR | DE | ...
+    topic_rank        INTEGER NOT NULL,               -- country 내 1..N (importance_score 내림차순)
+
+    topic_label       TEXT NOT NULL,                  -- LLM 생성 5~10 단어 한국어 (또는 fallback 시 "주요 뉴스 묶음")
+    summary           TEXT NOT NULL,                  -- LLM 생성 1~2 문장 factual (또는 fallback 시 top member ai_summary 첫 200자)
+
+    article_ids       JSONB NOT NULL,                 -- [doc_id, ...] 코드가 주입 (LLM 생성 금지)
+    article_count     INTEGER NOT NULL,               -- = jsonb_array_length(article_ids)
+
+    importance_score  DOUBLE PRECISION NOT NULL,      -- batch 내 country별 0~1 normalized (cross-country 비교)
+    raw_weight_sum    DOUBLE PRECISION NOT NULL,      -- 정규화 전 decay 가중합 (디버그 + day-over-day 트렌드)
+
+    centroid_sample   JSONB,                          -- 디버그: LLM 입력 doc id 목록 + summary hash
+    llm_model         VARCHAR(100),                   -- 사용된 모델 (primary/fallback 추적)
+    llm_fallback_used BOOLEAN NOT NULL DEFAULT FALSE, -- LLM 실패 시 minimal fallback 적용 여부
+
+    created_at        TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE INDEX idx_digest_topics_digest ON digest_topics (digest_id);
+CREATE INDEX idx_digest_topics_country ON digest_topics (country);
+CREATE INDEX idx_digest_topics_rank ON digest_topics (digest_id, country, topic_rank);

reports/phase2_final.md

@@ -0,0 +1,125 @@
+# Phase 2 최종 측정 보고서
+
+**측정일**: 2026-04-08
+**대상**: Document Server 검색 v2, Phase 2.1~2.3 통합
+**평가셋**: `tests/search_eval/queries.yaml` v0.1 (23 쿼리, 8 카테고리)
+**인프라 기준**: `memory/infra_inventory.md` (2026-04-08 실측)
+
+## A/B 결과
+
+| metric | Phase 1.3 baseline (A) | Phase 2 final (B) | Δ |
+|---|---|---|---|
+| Recall@10 | 0.730 | **0.737** | +0.007 ✓ |
+| MRR@10 | 0.795 | 0.797 | +0.002 |
+| NDCG@10 | 0.663 | **0.668** | +0.005 ✓ |
+| Top-3 hit | 0.900 | 0.900 | 0 |
+| Latency p50 | 114 ms | 109 ms | -5 |
+| Latency p95 | 171 ms | **256 ms** | +85 |
+
+## 카테고리별
+
+| category | A NDCG | B NDCG | Δ | 비고 |
+|---|---|---|---|---|
+| exact_keyword | 0.96 | 0.96 | 0 | 회귀 0 ✓ |
+| natural_language_ko | 0.73 | 0.73 | 0 | 회귀 0 ✓ (narrowed multilingual 덕) |
+| crosslingual_ko_en | 0.53 | 0.53 | 0 | bge-m3 한계 — multilingual 효과 0 |
+| **news_crosslingual** | 0.27 | **0.37** | **+0.10** | 개선 ✓ |
+| news_ko | 0.36 | 0.37 | +0.01 | 미세 |
+| news_en | 0.00 | 0.00 | 0 | 여전히 0 |
+| news_fr | 0.46 | 0.46 | 0 | |
+| other_domain | 0.88 | 0.88 | 0 | |
+
+## Phase 2 게이트 검증
+
+| 게이트 | 목표 | 실제 | 상태 |
+|---|---|---|---|
+| Recall@10 | ≥ 0.78 | 0.737 | ❌ (-0.043) |
+| Top-3 hit | ≥ 0.93 | 0.900 | ❌ (-0.030) |
+| crosslingual_ko_en NDCG | ≥ 0.65 | 0.53 | ❌ (-0.12) |
+| news_crosslingual NDCG | ≥ 0.30 | 0.37 | ✓ |
+| latency p95 | < 400 ms | 256 ms | ✓ |
+| 평가셋 v0.2 완료 | - | v0.1만 | ❌ (후속) |
+
+**2/6 통과** — 목표 미달. 단 회귀 0 + 일부 영역 개선.
+
+## Phase 2에서 실제로 달성한 것
+
+### 1. 아키텍처 — QueryAnalyzer async-only 구조 확립
+실측 기반 철학 수정 (memory `feedback_analyzer_async_only.md`):
+- `query → retrieval (즉시)` + `→ analyzer (async) → cache`
+- retrieval 경로에 LLM 동기 호출 0
+- background semaphore=1 (MLX single-inference 큐 폭발 방지)
+- prewarm 15개 startup 시 자동 실행
+- cache hit rate 첫 사용자 요청부터 70%+
+
+### 2. 실측 데이터 — MLX 한계
+gemma-4-26b-a4b-it-8bit MLX:
+- full prompt (prompt_tok=2406) → **10.5초**
+- 축소 prompt (prompt_tok=802) → **7~11초**
+- concurrency >1 시 → **timeout 폭발** (semaphore=1 필수)
+- 결론: analyzer는 **즉시 쓸 수 없는 자원**
+
+### 3. multilingual narrowing — domain별 효과 차등
+- 전 도메인 multilingual: natural_language_ko **-0.10 악화** ❌
+- `domain_hint == news OR language_scope == global` 한정: 회귀 0 + news_crosslingual **+0.10** ✓
+- 룰: 한국어 법령 검색에 영어 번역 쿼리 섞으면 noise
+
+### 4. soft_filter boost — 보수적 설정 필요
+- 초기 0.03+0.02 → exact_keyword **-0.03 악화**
+- 낮춰서 0.01 단일 domain only → 회귀 0
+- 평가셋에 filter 쿼리가 없어 효과 직접 측정 불가 (v0.2 확장 후 재평가)
+
+## Phase 2에서 달성하지 못한 것 + 이유
+
+### Recall@10 / Top-3 hit 회복 (0.730 → 0.78+ 미달)
+- baseline 대비 +0.007 미세 개선만
+- 원인: **corpus 1022 docs로 noise 증가**. chunk 수 7129. bge-m3의 embedding 공간에서 상위 후보 밀도 높아짐
+- 해결책: retrieval 단계 품질 (Phase 3 evidence extraction) 또는 embedding 모델 업그레이드
+
+### crosslingual_ko_en NDCG 0.65+ 미달 (0.53 정체)
+- multilingual translation이 효과 없음
+- 원인: 현재 category 3개 쿼리 중 정답 doc이 영어 교재 (Industrial Safety and Health Management 등). bge-m3는 ko 쿼리로 이 영어 doc을 약 0.5~0.6 cosine으로 이미 찾음. translation 추가가 정보 증가 없음
+- 실제 필요: **reranker가 crosslingual pair**를 더 잘 학습해야 함 → bge-reranker-v2-m3의 한계 영역
+
+### 평가셋 v0.2 완전 작성
+- 시간 제약 + 정답 doc_id 수동 라벨링 필요
+- 후속 작업으로 분리
+
+## Phase 2 기여 commits (시간순)
+
+```
+d28ef2f Phase 2.1 QueryAnalyzer + LRU cache + confidence 3-tier (초기)
+c81b728 async-only 구조 전환 (철학 수정)
+324537c LLM_TIMEOUT_MS 5000 → 15000 (실측 반영)
+1e80d4c setup_logger 수정 (prewarm 로그 보이도록)
+f5c3dea Phase 2.2 multilingual + query embed cache
+21a78fb semaphore concurrency=1 + run_eval --analyze 파라미터
+e595283 multilingual news/global 한정 narrowing
+e91c199 Phase 2.3 soft_filter boost (초기)
+01f144a soft_filter boost 약화 (0.01, doctype 제거)
+```
+
+## 다음 단계 선택지 (사용자 결정)
+
+### A. Phase 2 종료 + Phase 3 진입 (권장)
+- Phase 2 성과: 아키텍처 + 회귀 0 + news 영역 개선 + 실측 기반 철학 확립
+- Recall/crosslingual 정체는 **Phase 2 범위 밖** — embedding/reranker 교체 혹은 Phase 3 evidence extraction으로 우회
+- Phase 3 (evidence extraction + grounded synthesis + `/api/search/ask`) 착수
+
+### B. Phase 2 iteration — embedding 실험
+- bge-m3 → 다른 embedding (e.g., multilingual-e5-large-instruct, jina-embeddings-v3) 교체 실험
+- 대규모 재인덱싱 필요 (1022 docs × chunks)
+- 인프라 변경이므로 infra_inventory.md drift 발생
+
+### C. Phase 2 iteration — 평가셋 v0.2 작성
+- queries_v0.2.yaml 작성 (filter 쿼리 + graded relevance)
+- 현재 Phase 2 코드의 filter 효과 측정
+- 단, Recall/crosslingual 근본 해결은 아님
+
+## Soft Lock 준수 확인 (infra_inventory.md)
+
+- ✓ `config.yaml` 변경 없음 (GPU local override 그대로)
+- ✓ `docker compose restart` 사용 안 함 (`up -d --build fastapi`만)
+- ✓ Ollama 모델 pull/remove 없음 (bge-m3, exaone3.5 그대로)
+- ✓ Reranker 모델 변경 없음 (TEI bge-reranker-v2-m3 그대로)
+- ✓ Mac mini MLX 설정 변경 없음

reports/phase2_final_baseline.csv

@@ -0,0 +1,24 @@
+label,id,category,intent,domain_hint,query,relevant_ids,returned_ids_top10,latency_ms,recall_at_10,mrr_at_10,ndcg_at_10,top3_hit,error
+single,kw_001,exact_keyword,fact_lookup,document,산업안전보건법 제6장,3856;3868;3879,3856;3851;3862;3853;3861;3868;3879;3873;3876;3871,95.5,1.000,1.000,0.793,1,
+single,kw_002,exact_keyword,fact_lookup,document,중대재해 처벌 등에 관한 법률 제2장 중대산업재해,3917;3921,3921;3917;3919;3923;3916;3874;3918;3854;3922;3920,120.7,1.000,1.000,1.000,1,
+single,kw_003,exact_keyword,fact_lookup,document,화학물질관리법 유해화학물질 영업자,3981,3981;3985;3980;3984;3993;3857;3978;3986;3983;3957,120.2,1.000,1.000,1.000,1,
+single,kw_004,exact_keyword,fact_lookup,document,근로기준법 안전과 보건,4041,4041;3852;3851;3877;3905;3903;3858;3881;3781;3912,139.3,1.000,1.000,1.000,1,
+single,kw_005,exact_keyword,fact_lookup,document,산업안전보건기준에 관한 규칙 보호구,3888,3888;3912;3911;3905;3909;3889;3910;3897;3890;3896,157.8,1.000,1.000,1.000,1,
+single,nl_001,natural_language_ko,semantic_search,document,기계로 인한 산업재해 관련 법령,3856;3868;3879;3854,3878;3897;3863;3868;3879;3856;3895;3867;3851;3854,85.9,1.000,0.250,0.571,0,
+single,nl_002,natural_language_ko,semantic_search,document,사업주가 도급을 줄 때 산업재해를 예방하기 위해 해야 할 일,3855;3867;3878,3855;3917;3854;3867;3878;3863;3851;3908;3903;3895,82.1,1.000,1.000,0.853,1,
+single,nl_003,natural_language_ko,semantic_search,document,유해화학물질을 다루는 회사가 지켜야 할 안전 의무,3980;3981;3982,3980;3903;3904;3905;3981;3985;3896;3917;3857;3909,117.0,0.667,1.000,0.651,1,
+single,nl_004,natural_language_ko,semantic_search,document,중대재해가 발생했을 때 경영책임자가 처벌받는 기준,3916;3917;3920;3921,3917;3918;3916;3923;3919;3921;3854;3872;3877;3922,113.6,0.750,1.000,0.725,1,
+single,nl_005,natural_language_ko,semantic_search,document,안전보건교육은 누가 받아야 하고 어떤 내용을 다루는가,3853;3865,3853;4025;3876;3879;3859;3865;3781;3815;3818;3787,80.6,1.000,1.000,0.832,1,
+single,cl_001,crosslingual_ko_en,semantic_search,document,기계 안전 가드 설계 원리,3770;3856,3770;4540;3817;4541;3774;3816;3787;3758;3793;3773,79.0,0.500,1.000,0.613,1,
+single,cl_002,crosslingual_ko_en,semantic_search,document,산업 안전 입문서,3755;3775;3776;3777,3760;3755;3774;3764;3758;3775;3779;3802;3814;3817,107.6,0.500,0.500,0.385,1,
+single,cl_003,crosslingual_ko_en,semantic_search,document,전기 안전 위험,3772;3790,3897;3772;3771;4018;3773;3790;3819;4020;3807;3755,125.6,1.000,0.500,0.605,1,
+single,news_001,news_ko,semantic_search,news,이란과 미국의 군사 충돌,4303;4304;4307;4316;4322;4323;4327;4335,4317;4321;4771;4446;4743;4452;4307;4418;4331;4744,94.5,0.125,0.143,0.084,1,
+single,news_002,news_ko,semantic_search,news,호르무즈 해협 봉쇄,4316;4320;4322;4327,4327;4346;4349;4762;4767;4759;4322;4320;4340;4304,94.3,0.750,1.000,0.644,0,
+single,news_003,news_en,semantic_search,news,Trump Iran ultimatum,4258;4260;4262,4776;4515;4519;4658;4644;4763;4333;4762;4679;4321,118.7,0.000,0.000,0.000,1,
+single,news_004,news_fr,semantic_search,news,guerre en Iran,4199;4202;4210;4361;4363;4507;4519;4521,4678;4507;4199;4688;4776;4363;4519;4668;4670;4672,119.6,0.500,0.500,0.460,1,
+single,news_005,news_crosslingual,semantic_search,news,이란 미국 전쟁 글로벌 반응,4202;4258;4262;4536;4303;4304;4316,4262;4457;4765;4324;4345;4329;4452;4443;4761;4642,95.6,0.143,1.000,0.275,1,
+single,misc_001,other_domain,fact_lookup,document,강체의 평면 운동학,4063;4065,4063;4065;4064;4067;4071;4068;4069;4062;4060;4066,172.3,1.000,1.000,1.000,1,
+single,misc_002,other_domain,semantic_search,document,질점의 운동역학,4060;4061;4062,4062;4060;4070;4064;4068;4067;4065;4058;4071;4066,261.8,0.667,1.000,0.765,1,
+single,fail_001,failure_expected,semantic_search,document,Rust async runtime tokio scheduler 내부 구조,,4815;4069;4546;4062;4547;3801;3787;3812;4542;3770,118.6,0.000,0.000,0.000,1,
+single,fail_002,failure_expected,semantic_search,document,양자컴퓨터 큐비트 디코히어런스,,4058;4057;4067;3800;4065;4068;3817;4063;4064;3915,76.9,0.000,0.000,0.000,1,
+single,fail_003,failure_expected,semantic_search,news,재즈 보컬리스트 빌리 홀리데이,,4634;4100;4815;4116;4281;4697;4205;4077;4235;4758,73.6,0.000,0.000,0.000,1,

reports/phase2_final_candidate.csv

@@ -0,0 +1,24 @@
+label,id,category,intent,domain_hint,query,relevant_ids,returned_ids_top10,latency_ms,recall_at_10,mrr_at_10,ndcg_at_10,top3_hit,error
+single,kw_001,exact_keyword,fact_lookup,document,산업안전보건법 제6장,3856;3868;3879,3856;3851;3862;3853;3861;3868;3879;3873;3876;3871,67.9,1.000,1.000,0.793,1,
+single,kw_002,exact_keyword,fact_lookup,document,중대재해 처벌 등에 관한 법률 제2장 중대산업재해,3917;3921,3921;3917;3919;3923;3916;3874;3918;3854;3922;3920,110.0,1.000,1.000,1.000,1,
+single,kw_003,exact_keyword,fact_lookup,document,화학물질관리법 유해화학물질 영업자,3981,3981;3985;3980;3984;3993;3857;3978;3986;3983;3957,119.3,1.000,1.000,1.000,1,
+single,kw_004,exact_keyword,fact_lookup,document,근로기준법 안전과 보건,4041,4041;3852;3851;3877;3905;3903;3858;3881;3781;3912,108.7,1.000,1.000,1.000,1,
+single,kw_005,exact_keyword,fact_lookup,document,산업안전보건기준에 관한 규칙 보호구,3888,3888;3912;3911;3905;3909;3889;3910;3897;3890;3896,125.5,1.000,1.000,1.000,1,
+single,nl_001,natural_language_ko,semantic_search,document,기계로 인한 산업재해 관련 법령,3856;3868;3879;3854,3878;3897;3863;3868;3856;3879;3895;3867;3851;3854,83.9,1.000,0.250,0.571,0,
+single,nl_002,natural_language_ko,semantic_search,document,사업주가 도급을 줄 때 산업재해를 예방하기 위해 해야 할 일,3855;3867;3878,3855;3917;3854;3867;3878;3863;3851;3908;3903;3895,118.0,1.000,1.000,0.853,1,
+single,nl_003,natural_language_ko,semantic_search,document,유해화학물질을 다루는 회사가 지켜야 할 안전 의무,3980;3981;3982,3980;3903;3904;3905;3981;3985;3896;3917;3857;3909,82.8,0.667,1.000,0.651,1,
+single,nl_004,natural_language_ko,semantic_search,document,중대재해가 발생했을 때 경영책임자가 처벌받는 기준,3916;3917;3920;3921,3917;3918;3916;3923;3919;3921;3854;3872;3877;3922,72.1,0.750,1.000,0.725,1,
+single,nl_005,natural_language_ko,semantic_search,document,안전보건교육은 누가 받아야 하고 어떤 내용을 다루는가,3853;3865,3853;4025;3876;3879;3859;3865;3781;3815;3818;3787,80.2,1.000,1.000,0.832,1,
+single,cl_001,crosslingual_ko_en,semantic_search,document,기계 안전 가드 설계 원리,3770;3856,3770;4540;3817;4541;3774;3816;3787;3758;3793;3773,108.3,0.500,1.000,0.613,1,
+single,cl_002,crosslingual_ko_en,semantic_search,document,산업 안전 입문서,3755;3775;3776;3777,3760;3755;3774;3764;3758;3775;3779;3802;3814;3817,79.5,0.500,0.500,0.385,1,
+single,cl_003,crosslingual_ko_en,semantic_search,document,전기 안전 위험,3772;3790,3897;3772;3771;4018;3773;3790;3819;4020;3807;3755,103.7,1.000,0.500,0.605,1,
+single,news_001,news_ko,semantic_search,news,이란과 미국의 군사 충돌,4303;4304;4307;4316;4322;4323;4327;4335,4317;4321;4771;4743;4307;4452;4761;4678;4418;4331,1445.8,0.125,0.200,0.098,1,
+single,news_002,news_ko,semantic_search,news,호르무즈 해협 봉쇄,4316;4320;4322;4327,4327;4346;4349;4762;4767;4759;4322;4320;4340;4304,185.3,0.750,1.000,0.644,0,
+single,news_003,news_en,semantic_search,news,Trump Iran ultimatum,4258;4260;4262,4776;4515;4519;4658;4644;4763;4333;4762;4679;4321,76.3,0.000,0.000,0.000,1,
+single,news_004,news_fr,semantic_search,news,guerre en Iran,4199;4202;4210;4361;4363;4507;4519;4521,4678;4507;4199;4688;4776;4363;4519;4668;4670;4672,157.9,0.500,0.500,0.460,1,
+single,news_005,news_crosslingual,semantic_search,news,이란 미국 전쟁 글로벌 반응,4202;4258;4262;4536;4303;4304;4316,4262;4457;4765;4324;4345;4329;4258;4452;4443;4761,186.7,0.286,1.000,0.367,1,
+single,misc_001,other_domain,fact_lookup,document,강체의 평면 운동학,4063;4065,4063;4065;4064;4067;4071;4068;4069;4062;4060;4066,171.6,1.000,1.000,1.000,1,
+single,misc_002,other_domain,semantic_search,document,질점의 운동역학,4060;4061;4062,4062;4060;4070;4064;4068;4067;4065;4058;4071;4066,263.6,0.667,1.000,0.765,1,
+single,fail_001,failure_expected,semantic_search,document,Rust async runtime tokio scheduler 내부 구조,,4815;4069;4546;4062;4547;3801;3787;3812;4542;3770,121.9,0.000,0.000,0.000,1,
+single,fail_002,failure_expected,semantic_search,document,양자컴퓨터 큐비트 디코히어런스,,4058;4057;4067;3800;4065;4068;3817;4063;4064;3915,75.2,0.000,0.000,0.000,1,
+single,fail_003,failure_expected,semantic_search,news,재즈 보컬리스트 빌리 홀리데이,,4634;4100;4815;4116;4281;4697;4205;4077;4235;4289,73.9,0.000,0.000,0.000,1,

tests/search_eval/run_eval.py

@@ -134,6 +134,7 @@ async def call_search(
     limit: int = 20,
     fusion: str | None = None,
     rerank: str | None = None,
+    analyze: str | None = None,
 ) -> tuple[list[int], float]:
     """검색 API 호출 → (doc_ids, latency_ms)."""
     url = f"{base_url.rstrip('/')}/api/search/"
@@ -143,6 +144,8 @@ async def call_search(
         params["fusion"] = fusion
     if rerank is not None:
         params["rerank"] = rerank
+    if analyze is not None:
+        params["analyze"] = analyze
 
     import time
 
@@ -169,6 +172,7 @@ async def evaluate(
     mode: str = "hybrid",
     fusion: str | None = None,
     rerank: str | None = None,
+    analyze: str | None = None,
 ) -> list[QueryResult]:
     """전체 쿼리셋 평가."""
     results: list[QueryResult] = []
@@ -177,7 +181,7 @@ async def evaluate(
         for q in queries:
             try:
                 returned_ids, latency_ms = await call_search(
-                    client, base_url, token, q.query, mode=mode, fusion=fusion, rerank=rerank
+                    client, base_url, token, q.query, mode=mode, fusion=fusion, rerank=rerank, analyze=analyze
                 )
                 results.append(
                     QueryResult(
@@ -415,6 +419,13 @@ def main() -> int:
         choices=["true", "false"],
         help="bge-reranker-v2-m3 활성화 (Phase 1.3+, 미지정 시 서버 기본값=true)",
     )
+    parser.add_argument(
+        "--analyze",
+        type=str,
+        default=None,
+        choices=["true", "false"],
+        help="QueryAnalyzer 활성화 (Phase 2.1+, cache hit 시 multilingual 적용)",
+    )
     parser.add_argument(
         "--token",
         type=str,
@@ -454,21 +465,21 @@ def main() -> int:
     if args.base_url:
         print(f"\n>>> evaluating: {args.base_url}")
         results = asyncio.run(
-            evaluate(queries, args.base_url, args.token, "single", mode=args.mode, fusion=args.fusion, rerank=args.rerank)
+            evaluate(queries, args.base_url, args.token, "single", mode=args.mode, fusion=args.fusion, rerank=args.rerank, analyze=args.analyze)
         )
         print_summary("single", results)
         all_results.extend(results)
     else:
         print(f"\n>>> baseline: {args.baseline_url}")
         baseline_results = asyncio.run(
-            evaluate(queries, args.baseline_url, args.token, "baseline", mode=args.mode, fusion=args.fusion, rerank=args.rerank)
+            evaluate(queries, args.baseline_url, args.token, "baseline", mode=args.mode, fusion=args.fusion, rerank=args.rerank, analyze=args.analyze)
         )
         baseline_summary = print_summary("baseline", baseline_results)
 
         print(f"\n>>> candidate: {args.candidate_url}")
         candidate_results = asyncio.run(
             evaluate(
-                queries, args.candidate_url, args.token, "candidate", mode=args.mode, fusion=args.fusion, rerank=args.rerank
+                queries, args.candidate_url, args.token, "candidate", mode=args.mode, fusion=args.fusion, rerank=args.rerank, analyze=args.analyze
             )
         )
         candidate_summary = print_summary("candidate", candidate_results)