diff --git a/backend/data/vault/产品/RAG 检索增强与引用定位.md b/backend/data/vault/产品/RAG 检索增强与引用定位.md
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+---
+title: RAG 检索增强与引用定位
+tags: RAG, 产品
+---
+
+# RAG 概述
+
+检索增强生成先检索相关文档块，再交给大模型生成回答。
+
+## Citation 引用
+
+每个搜索结果附带 Citation，包含文件路径与起止偏移量。
+
+前端可根据偏移量跳转到笔记中的原始位置。
+
+## Reranker 精排
+
+粗排后使用 Reranker 对候选块重新打分，提升相关性。
diff --git a/backend/data/vault/日记/2026-08-27 周会.md b/backend/data/vault/日记/2026-08-27 周会.md
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+---
+title: 周会纪要
+tags: 会议, 日记
+---
+
+# 周会纪要
+
+今天讨论了三件事：索引重建、混合检索、前端联调。
+
+Vector index rebuild 任务需要支持增量更新。
+
+下次会议在周五，记得同步接口契约。
diff --git a/backend/data/vault/编程/Python 基础语法.md b/backend/data/vault/编程/Python 基础语法.md
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+---
+title: Python 基础语法
+tags: python, 编程
+---
+
+# 变量与类型
+
+Python 是动态类型语言，变量无需声明类型。
+
+整数、浮点数、字符串、布尔值是四种基本类型。
+
+## 列表与字典
+
+列表用方括号，字典用花括号。列表推导式非常常用。
+
+### 函数定义
+
+使用 def 关键字定义函数，支持默认参数与关键字参数。
diff --git a/backend/data/vault/编程/向量数据库与相似度检索.md b/backend/data/vault/编程/向量数据库与相似度检索.md
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+---
+title: 向量数据库与相似度检索
+tags: 向量数据库, 检索
+---
+
+# 向量数据库
+
+向量数据库用于存储高维向量并支持近似最近邻检索。
+
+常用相似度度量有余弦相似度与欧氏距离。
+
+## sqlite-vec
+
+sqlite-vec 是一个轻量的 SQLite 向量扩展，支持 vec0 虚拟表。
+
+可以存储 float32 向量，并通过 KNN 查询相近向量。
+
+## 混合检索
+
+结合全文检索与向量检索，用 RRF 融合排序结果。
diff --git a/backend/data/vault/项目说明.md b/backend/data/vault/项目说明.md
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+---
+title: Notes Agentic 项目说明
+tags: 项目
+---
+
+# 项目说明
+
+这是一个 AI 笔记软件，支持 Markdown 块级索引与混合检索。
+
+后端基于 FastAPI，检索使用 SQLite FTS5 与 sqlite-vec 向量检索。
diff --git a/backend/tests/conftest.py b/backend/tests/conftest.py
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+++ b/backend/tests/conftest.py
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+"""pytest 全局隔离：把所有测试的数据目录/数据库/Vault 重定向到临时目录。
+
+这样测试不会读写真实的 backend/data（真实索引与笔记），也使得「默认库应为空」这类
+断言在任意本机状态下都确定成立——即使开发者已在本地跑过 rebuild。
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from app.config import get_settings
+
+
+@pytest.fixture(autouse=True)
+def _isolate_data_dir(tmp_path, monkeypatch):
+    data_dir = tmp_path / "data"
+    monkeypatch.setenv("APP_DATA_DIR", str(data_dir))
+    monkeypatch.setenv("APP_DB_PATH", str(data_dir / "app.db"))
+    monkeypatch.setenv("APP_VAULT_PATH", str(tmp_path / "vault"))
+    # 清除 lru 缓存，让本次测试内的 get_settings() 读到临时目录
+    get_settings.cache_clear()
+    yield
+    get_settings.cache_clear()
diff --git a/backend/tests/test_retrieval.py b/backend/tests/test_retrieval.py
new file mode 100644
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+++ b/backend/tests/test_retrieval.py
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+"""Knowledge / Retrieval Core 的单元与端到端测试。
+
+端到端用例通过 monkeypatch 将 APP_DATA_DIR / APP_DB_PATH / APP_VAULT_PATH 指到临时目录，
+并清理 get_settings 缓存，保证不读写 backend/data 下的真实索引，也不污染其他测试。
+"""
+
+from __future__ import annotations
+
+import asyncio
+from datetime import datetime, timezone
+
+import pytest
+
+from app.config import get_settings
+from app.contracts import IndexRebuildRequest, SearchMode, SearchRequest
+from app.knowledge.parser import note_id_for_path, parse_note
+from app.retrieval.embedding import HashEmbeddingProvider
+from app.retrieval.hybrid import rrf_fuse
+from app.textutils import match_query, tokens
+
+MD = """---
+title: 测试标题
+tags: python, 检索
+---
+
+# 一级标题
+
+这是第一段正文。
+
+## 二级标题
+
+第二段正文内容。
+"""
+
+
+def _dt() -> datetime:
+    return datetime(2026, 8, 27, tzinfo=timezone.utc)
+
+
+@pytest.fixture
+def vault():
+    """返回 conftest 全局隔离后的临时 Vault 目录，用于写入示例笔记。"""
+    return get_settings().vault_path
+
+
+# --------------------------------------------------------------------------- #
+# 单元测试
+# --------------------------------------------------------------------------- #
+def test_parse_note_extracts_frontmatter_and_blocks() -> None:
+    parsed = parse_note(
+        markdown=MD, file_path="编程/测试.md", folder="编程",
+        tags=None, created_at=_dt(), updated_at=_dt(),
+    )
+
+    assert parsed.title == "测试标题"
+    assert parsed.tags == ["python", "检索"]
+    assert parsed.note_id == note_id_for_path("编程/测试.md")
+
+    paths = [tuple(b.heading_path) for b in parsed.blocks]
+    assert ("一级标题",) in paths
+    assert ("一级标题", "二级标题") in paths
+
+    # 每个 Block 的偏移合法且内容非空
+    for b in parsed.blocks:
+        assert 0 <= b.start_offset <= b.end_offset
+        assert b.content.strip()
+
+
+def test_block_ids_are_stable() -> None:
+    p1 = parse_note(markdown=MD, file_path="编程/测试.md", folder="编程",
+                    tags=None, created_at=_dt(), updated_at=_dt())
+    p2 = parse_note(markdown=MD, file_path="编程/测试.md", folder="编程",
+                    tags=None, created_at=_dt(), updated_at=_dt())
+
+    assert [b.block_id for b in p1.blocks] == [b.block_id for b in p2.blocks]
+    # block_id 前缀符合团队约定
+    assert all(b.block_id.startswith("blk_") for b in p1.blocks)
+
+
+def test_tokens_split_cjk_bigrams_and_match_query() -> None:
+    toks = tokens("向量检索")
+    assert "向" in toks and "量" in toks
+    assert "向量" in toks and "检索" in toks
+
+    q = match_query("python 向量")
+    assert '"python"' in q and '"向量"' in q
+
+
+def test_hash_embedding_is_deterministic_and_normalized() -> None:
+    emb = HashEmbeddingProvider()
+    v1 = asyncio.run(emb.embed_query("向量检索"))
+    v2 = asyncio.run(emb.embed_query("向量检索"))
+
+    assert v1 == v2
+    assert len(v1) == emb.dim == 128
+    norm = sum(x * x for x in v1) ** 0.5
+    assert abs(norm - 1.0) < 1e-6
+
+
+def test_rrf_fuse_merges_ranked_lists() -> None:
+    scores = rrf_fuse([["a", "b"], ["b", "a"]])
+
+    assert set(scores) == {"a", "b"}
+    assert scores["a"] > 0 and scores["b"] > 0
+
+
+# --------------------------------------------------------------------------- #
+# 端到端测试（隔离环境）
+# --------------------------------------------------------------------------- #
+SAMPLE_NOTES = {
+    "编程/向量.md": (
+        "---\ntitle: 向量数据库\ntags: 向量, 检索\n---\n\n"
+        "# 向量数据库\n\n向量数据库用于存储高维向量并支持近似最近邻检索。\n"
+    ),
+    "编程/Python.md": (
+        "---\ntitle: Python 基础\ntags: python\n---\n\n"
+        "# 变量\n\nPython 是动态类型语言。\n"
+    ),
+    "产品/RAG.md": (
+        "---\ntitle: RAG 概述\ntags: RAG\n---\n\n"
+        "# RAG\n\n检索增强生成先检索相关文档块。\n"
+    ),
+}
+
+
+def _write_vault(vault, files: dict[str, str]) -> None:
+    for rel, text in files.items():
+        path = vault / rel
+        path.parent.mkdir(parents=True, exist_ok=True)
+        path.write_text(text, encoding="utf-8")
+
+
+def test_rebuild_indexes_vault_and_lists_notes(vault) -> None:
+    from app.services import index_service, note_service
+
+    _write_vault(vault, SAMPLE_NOTES)
+
+    job = asyncio.run(index_service.rebuild(IndexRebuildRequest(scope="all")))
+    assert job.status == "completed"
+
+    items, total = note_service.list_notes(limit=50, offset=0, folder=None, tag=None)
+    assert total == 3
+    assert {i.file_path for i in items} == set(SAMPLE_NOTES)
+
+
+def test_search_returns_citations_for_each_mode(vault) -> None:
+    from app.retrieval.engine import engine
+    from app.services import index_service
+
+    _write_vault(vault, SAMPLE_NOTES)
+    asyncio.run(index_service.rebuild(IndexRebuildRequest(scope="all")))
+
+    # FTS：中文词组召回，且返回可定位的 Citation
+    fts = asyncio.run(engine.search(SearchRequest(query="向量数据库", mode=SearchMode.fts)))
+    assert fts.page.total >= 1
+    top = fts.items[0]
+    assert top.citation.citation_id.startswith("cit_")
+    assert top.citation.file_path == "编程/向量.md"
+    assert top.citation.block_id == top.block_id
+
+    # Vector：向量召回
+    vec = asyncio.run(engine.search(SearchRequest(query="向量数据库", mode=SearchMode.vector)))
+    assert vec.page.total >= 1
+
+    # Hybrid：RRF + Reranker 融合后仍有结果
+    hyb = asyncio.run(engine.search(SearchRequest(query="向量数据库", mode=SearchMode.hybrid)))
+    assert hyb.page.total >= 1
+    assert all(0.0 <= r.score <= 1.0 for r in hyb.items)
+
+
+def test_search_metadata_filters(vault) -> None:
+    from app.retrieval.engine import engine
+    from app.services import index_service
+
+    _write_vault(vault, SAMPLE_NOTES)
+    asyncio.run(index_service.rebuild(IndexRebuildRequest(scope="all")))
+
+    by_folder = asyncio.run(
+        engine.search(SearchRequest(query="检索", mode=SearchMode.hybrid, folders=["产品"]))
+    )
+    assert by_folder.page.total >= 1
+    assert all(r.file_path.startswith("产品/") for r in by_folder.items)
+
+    by_tag = asyncio.run(
+        engine.search(SearchRequest(query="向量", mode=SearchMode.hybrid, tags=["向量"]))
+    )
+    assert by_tag.page.total >= 1
+    assert all("向量" in r.citation.heading_path or "向量" in r.title for r in by_tag.items)
+
+
+def test_route_handlers_wired_to_services(vault) -> None:
+    """验证 routes.py 里 notes/search/index 端点已接入真实服务（而非 501 壳子）。"""
+    from app import routes
+    from app.contracts import NoteCreateRequest
+
+    _write_vault(vault, SAMPLE_NOTES)
+    job = asyncio.run(routes.rebuild_index(IndexRebuildRequest(scope="all")))
+    assert job.status == "completed"
+
+    notes = asyncio.run(routes.list_notes(limit=50, offset=0, folder=None, tag=None))
+    assert notes.page.total == 3
+
+    result = asyncio.run(routes.search_notes(SearchRequest(query="向量数据库", mode=SearchMode.hybrid)))
+    assert result.page.total >= 1
+    assert result.items[0].citation.citation_id.startswith("cit_")
+
+    created = asyncio.run(
+        routes.create_note(NoteCreateRequest(title="接口测试", markdown="# 接口\n\n正文。"))
+    )
+    assert created.title == "接口测试"
+    assert asyncio.run(routes.get_note(created.note_id)).note_id == created.note_id
+
+
+def test_get_missing_note_raises_404(vault) -> None:
+    from app import routes
+    from app.errors import ApiError
+
+    with pytest.raises(ApiError):
+        asyncio.run(routes.get_note("note_missing"))
+
+
+def test_note_crud_roundtrip(vault) -> None:
+    from app.retrieval.engine import engine
+    from app.services import note_service
+
+    note = asyncio.run(
+        note_service.create_note(title="新建笔记", markdown="# 标题\n\n内容。", folder="测试", tags=["测试"])
+    )
+    assert note.note_id.startswith("note_")
+    assert note.blocks
+
+    got = asyncio.run(note_service.get_note(note.note_id))
+    assert got is not None and got.title == "新建笔记"
+
+    updated = asyncio.run(
+        note_service.update_note(note.note_id, title="改名", markdown="# 新标题\n\n检索内容。")
+    )
+    assert updated.title == "改名"
+    assert updated.note_id == note.note_id  # 更新不改变 ID
+
+    # 更新后可检索到新内容
+    resp = asyncio.run(engine.search(SearchRequest(query="检索内容", mode=SearchMode.fts)))
+    assert any(r.note_id == note.note_id for r in resp.items)
+
+    assert asyncio.run(note_service.delete_note(note.note_id)) is True
+    assert asyncio.run(note_service.get_note(note.note_id)) is None