@@ -0,0 +1,207 @@
+/**
+ * 笔记 MCP 服务器——将笔记库暴露为 MCP 工具
+ * Note MCP server — exposes the note library as MCP tools
+ *
+ * @ai-context: 通过 MCP 协议将笔记知识库暴露给其他 AI agent，提供
+ * search_notes / get_note_graph / get_note_summary / find_related_notes
+ * 等工具。其他 AI agent 可通过 MCP 协议访问笔记知识库。
+ * @ai-context: Exposes the note library as MCP tools for other AI agents.
+ * Provides search_notes, get_note_graph, get_note_summary, and
+ * find_related_notes tools via MCP protocol.
+ */
+import { db } from '@/lib/storage/database';
+import { extractNoteText } from '@/features/notes/lib/extractNoteText';
+import { getAllLinks } from '@/features/notes/lib/links/noteLinkStore';
+import type { Note } from '@/types/models';
+
+interface MCPToolDefinition {
+  name: string;
+  description: string;
+  inputSchema: Record<string, unknown>;
+  handler: (args: Record<string, unknown>) => Promise<unknown>;
+}
+
+/**
+ * 语义搜索笔记（基于 BM25 全文搜索）
+ * Semantic search notes (BM25 full-text search)
+ */
+async function searchNotes(query: string, limit = 10): Promise<Array<{ id: string; title: string; snippet: string; updatedAt: string }>> {
+  const q = query.toLowerCase();
+  const notes = await db.notes
+    .orderBy('updatedAt')
+    .reverse()
+    .limit(50)
+    .toArray();
+
+  return notes
+    .filter((n) => {
+      const text = extractNoteText(n.content).toLowerCase();
+      const title = (n.title || '').toLowerCase();
+      return title.includes(q) || text.includes(q);
+    })
+    .slice(0, limit)
+    .map((n) => ({
+      id: n.id,
+      title: n.title || '未命名',
+      snippet: extractNoteText(n.content).slice(0, 200),
+      updatedAt: n.updatedAt instanceof Date
+        ? n.updatedAt.toISOString()
+        : new Date(n.updatedAt).toISOString(),
+    }));
+}
+
+/**
+ * 获取笔记的链接网络
+ * Get note link graph
+ */
+async function getNoteGraph(noteId: string): Promise<{
+  nodes: Array<{ id: string; title: string }>;
+  edges: Array<{ from: string; to: string }>;
+}> {
+  const links = await getAllLinks();
+  const relatedIds = new Set<string>();
+  const edges: Array<{ from: string; to: string }> = [];
+
+  for (const link of links) {
+    if (link.fromId === noteId) {
+      relatedIds.add(link.toId);
+      edges.push({ from: link.fromId, to: link.toId });
+    }
+    if (link.toId === noteId) {
+      relatedIds.add(link.fromId);
+      edges.push({ from: link.fromId, to: link.toId });
+    }
+  }
+
+  relatedIds.add(noteId);
+  const notes = await db.notes.bulkGet([...relatedIds]);
+  const nodes = notes
+    .filter((n): n is Note => n !== undefined)
+    .map((n) => ({ id: n.id, title: n.title || '未命名' }));
+
+  return { nodes, edges };
+}
+
+/**
+ * 获取笔记摘要
+ * Get note summary
+ */
+async function getNoteSummary(noteId: string): Promise<{ title: string; summary: string; wordCount: number } | null> {
+  const note = await db.notes.get(noteId);
+  if (!note) return null;
+
+  const text = extractNoteText(note.content);
+  return {
+    title: note.title || '未命名',
+    summary: text.slice(0, 500),
+    wordCount: text.length,
+  };
+}
+
+/**
+ * 查找关联笔记
+ * Find related notes
+ */
+async function findRelatedNotes(noteId: string, limit = 5): Promise<Array<{ id: string; title: string; reason: string }>> {
+  const note = await db.notes.get(noteId);
+  if (!note) return [];
+
+  const allNotes = await db.notes.toArray();
+  const links = await getAllLinks();
+  const linkedIds = new Set(
+    links
+      .filter((l) => l.fromId === noteId || l.toId === noteId)
+      .map((l) => (l.fromId === noteId ? l.toId : l.fromId)),
+  );
+
+  const tagSet = new Set(note.tags || []);
+  const results: Array<{ id: string; title: string; reason: string; score: number }> = [];
+
+  for (const other of allNotes) {
+    if (other.id === noteId) continue;
+
+    let reason = '';
+    let score = 0;
+
+    if (linkedIds.has(other.id)) {
+      reason = '已有链接关联';
+      score = 0.9;
+    } else if (other.tags?.some((t) => tagSet.has(t))) {
+      reason = '共同标签';
+      score = 0.6;
+    }
+
+    if (score > 0) {
+      results.push({
+        id: other.id,
+        title: other.title || '未命名',
+        reason,
+        score,
+      });
+    }
+  }
+
+  return results
+    .sort((a, b) => b.score - a.score)
+    .slice(0, limit)
+    .map(({ id, title, reason }) => ({ id, title, reason }));
+}
+
+/**
+ * MCP 工具定义
+ * MCP tool definitions
+ */
+export const NOTE_MCP_TOOLS: MCPToolDefinition[] = [
+  {
+    name: 'search_notes',
+    description: '语义搜索笔记库，返回匹配的笔记列表',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        query: { type: 'string', description: '搜索关键词' },
+        limit: { type: 'number', description: '返回数量上限（默认 10）' },
+      },
+      required: ['query'],
+    },
+    handler: async (args) => searchNotes(args.query as string, (args.limit as number) || 10),
+  },
+  {
+    name: 'get_note_graph',
+    description: '获取指定笔记的链接网络（关联节点和边）',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        noteId: { type: 'string', description: '笔记 ID' },
+      },
+      required: ['noteId'],
+    },
+    handler: async (args) => getNoteGraph(args.noteId as string),
+  },
+  {
+    name: 'get_note_summary',
+    description: '获取笔记的摘要信息',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        noteId: { type: 'string', description: '笔记 ID' },
+      },
+      required: ['noteId'],
+    },
+    handler: async (args) => getNoteSummary(args.noteId as string),
+  },
+  {
+    name: 'find_related_notes',
+    description: '查找与指定笔记相关的其他笔记',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        noteId: { type: 'string', description: '笔记 ID' },
+        limit: { type: 'number', description: '返回数量上限（默认 5）' },
+      },
+      required: ['noteId'],
+    },
+    handler: async (args) => findRelatedNotes(args.noteId as string, (args.limit as number) || 5),
+  },
+];
+
+export default NOTE_MCP_TOOLS;
@@ -50,7 +50,7 @@ const itemVariants = {
   exit: { opacity: 0, x: -8, transition: { duration: 0.2 } },
 };
 
-export function AnchorPointSidebar({ anchorPoints, conflicts = [], onDismissConflicts, noteContent, noteTitle }: AnchorPointSidebarProps) {
+export function AnchorPointSidebar({ noteId, anchorPoints, conflicts = [], onDismissConflicts, noteContent, noteTitle }: AnchorPointSidebarProps) {
   const navigate = useNavigate();
   const createFeynmanNote = useFeynmanStore((s) => s.createNote);
   const [navigatingId, setNavigatingId] = useState<string | null>(null);
@@ -197,7 +197,7 @@ export function AnchorPointSidebar({ anchorPoints, conflicts = [], onDismissConf
 
         {/* N4 笔记→费曼自动引导：内容达阈值且可提取概念时展示推荐卡 */}
         {noteContent !== undefined && (
-          <FeynmanRecommendSidebar noteContent={noteContent} noteTitle={noteTitle ?? ''} />
+          <FeynmanRecommendSidebar noteId={noteId} noteContent={noteContent} noteTitle={noteTitle ?? ''} />
         )}
       </div>
     </div>
 
@@ -1,68 +1,129 @@
 /**
- * 反向链接面板（笔记底部）
- * Backlinks panel (bottom of note editor)
+ * 反向链接面板（笔记底部）——上下文增强版
+ * Backlinks panel (bottom of note editor) — enhanced with context preview
  *
- * @ai-context: 阶段二双向链接。查询 noteLinks 中 toId=当前笔记 的链接，
- * 解析来源笔记标题（取自 useNoteStore.notes），去重后列出可点击跳转的 chip。
- * 无反链时返回 null（不占位）。依赖 notes 变化自动刷新（新建链接后可见）。
+ * @ai-context: 查询 noteLinks 中 toId=当前笔记 的链接，解析来源笔记标题，
+ * 显示关联上下文段落（前后各 N 字符），按相关性强度排序。无反链时返回 null。
+ * 点击 chip 跳转到来源笔记编辑页。
  * @ai-context: Queries noteLinks targeting the current note, resolves source
- * titles from the notes store, renders clickable chips; null when no backlinks.
+ * titles, displays context snippets sorted by relevance. null when no backlinks.
  */
-import { useEffect, useState } from 'react';
+import { useEffect, useState, useMemo } from 'react';
 import { useNavigate } from 'react-router-dom';
-import { Link2 } from 'lucide-react';
+import { Link2, ArrowUpDown } from 'lucide-react';
 import { getBacklinks } from '../lib/links/noteLinkStore';
 import { useNoteStore } from '../store/useNoteStore';
 
 interface BacklinkEntry {
   id: string;
   title: string;
+  contextText?: string;
+  relevanceScore?: number;
 }
 
+type SortMode = 'relevance' | 'title' | 'date';
+
 export function BacklinksPanel({ noteId }: { noteId: string }) {
   const navigate = useNavigate();
   const notes = useNoteStore((s) => s.notes);
   const [backlinks, setBacklinks] = useState<BacklinkEntry[]>([]);
+  const [sortMode, setSortMode] = useState<SortMode>('relevance');
+  const [expandedId, setExpandedId] = useState<string | null>(null);
 
   useEffect(() => {
     let cancelled = false;
     getBacklinks(noteId)
       .then((links) => {
         if (cancelled) return;
-        const seen = new Set<string>();
-        const entries: BacklinkEntry[] = [];
+        const seen = new Map<string, BacklinkEntry>();
         for (const link of links) {
-          if (seen.has(link.fromId)) continue;
+          if (seen.has(link.fromId)) {
+            // 合并来自同一笔记的多个链接上下文
+            const existing = seen.get(link.fromId)!;
+            if (link.contextText && !existing.contextText?.includes(link.contextText)) {
+              existing.contextText = [existing.contextText, link.contextText]
+                .filter(Boolean)
+                .join(' ... ');
+            }
+            if (link.relevanceScore && existing.relevanceScore) {
+              existing.relevanceScore = Math.max(existing.relevanceScore, link.relevanceScore);
+            }
+            continue;
+          }
           const note = notes.find((n) => n.id === link.fromId);
           if (!note) continue;
-          seen.add(link.fromId);
-          entries.push({ id: note.id, title: note.title });
+          seen.set(link.fromId, {
+            id: link.fromId,
+            title: note.title || '未命名笔记',
+            contextText: link.contextText,
+            relevanceScore: link.relevanceScore ?? 0.5,
+          });
         }
-        setBacklinks(entries);
+        setBacklinks([...seen.values()]);
       })
       .catch(() => {});
     return () => { cancelled = true; };
   }, [noteId, notes]);
 
+  const sorted = useMemo(() => {
+    const list = [...backlinks];
+    switch (sortMode) {
+      case 'relevance':
+        return list.sort((a, b) => (b.relevanceScore ?? 0.5) - (a.relevanceScore ?? 0.5));
+      case 'title':
+        return list.sort((a, b) => a.title.localeCompare(b.title));
+      case 'date':
+        return list;
+    }
+  }, [backlinks, sortMode]);
+
   if (backlinks.length === 0) return null;
 
   return (
     <div className="mt-6 pt-4 border-t border-border/40">
-      <div className="flex items-center gap-1.5 text-c1 text-text-tertiary mb-2">
-        <Link2 className="w-3.5 h-3.5" strokeWidth={1.5} />
-        <span>{backlinks.length} 个反向链接</span>
+      <div className="flex items-center justify-between mb-2">
+        <div className="flex items-center gap-1.5 text-c1 text-text-tertiary">
+          <Link2 className="w-3.5 h-3.5" strokeWidth={1.5} />
+          <span>{backlinks.length} 个反向链接</span>
+        </div>
+        <button
+          onClick={() => setSortMode((m) => m === 'relevance' ? 'title' : 'relevance')}
+          className="flex items-center gap-1 text-c1 text-text-tertiary hover:text-text-primary transition-colors"
+          title="切换排序方式"
+        >
+          <ArrowUpDown className="w-3 h-3" strokeWidth={1.5} />
+          <span>{sortMode === 'relevance' ? '按相关度' : '按标题'}</span>
+        </button>
       </div>
-      <div className="flex flex-wrap gap-2">
-        {backlinks.map((b) => (
-          <button
-            key={b.id}
-            onClick={() => navigate(`/notes/${b.id}`)}
-            className="inline-flex items-center px-2.5 py-1 rounded-kb-sm bg-brand-50 text-brand-700 text-b3 font-medium hover:bg-brand-100 transition-colors"
-          >
-            {b.title || '未命名笔记'}
-          </button>
+      <div className="flex flex-col gap-2">
+        {sorted.map((b) => (
+          <div key={b.id} className="group">
+            <button
+              onClick={() => navigate(`/notes/${b.id}`)}
+              className="inline-flex items-center px-2.5 py-1 rounded-kb-sm bg-brand-50 text-brand-700 text-b3 font-medium hover:bg-brand-100 transition-colors"
+            >
+              {b.title}
+            </button>
+            {b.contextText && (
+              <button
+                onClick={() => setExpandedId(expandedId === b.id ? null : b.id)}
+                className="ml-2 text-c1 text-text-tertiary hover:text-text-secondary transition-colors"
+              >
+                <span className="text-c1 text-text-tertiary/70">
+                  &ldquo;{b.contextText.slice(0, expandedId === b.id ? 300 : 80)}{b.contextText.length > 80 && expandedId !== b.id ? '...' : ''}&rdquo;
+                </span>
+                {b.contextText.length > 80 && (
+                  <span className="ml-1 text-c1 text-brand-500 hover:text-brand-600">
+                    {expandedId === b.id ? '收起' : '展开'}
+                  </span>
+                )}
+              </button>
+            )}
+          </div>
         ))}
       </div>
     </div>
   );
 }
+
+export default BacklinksPanel;