feat: pgvector integration — auto-embed documents on build --graph

- Add InitPGVector() and SyncPGVectorDocuments() to agestore
- ccg build --graph now syncs AGE graph + pgvector documents
- Documents include node name + annotations as content, metadata as JSONB
- mcp-pgvector-server handles embedding generation automatically
- Update .mcp.json with pgvector MCP server config

Flow: ccg build --graph → GORM + AGE + pgvector table →
      mcp-pgvector-server generates embeddings →
      Claude uses semantic search via pgvector MCP

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: tae2089

.mcp.json

@@ -3,6 +3,13 @@
     "ccg": {
       "command": "./ccg",
       "args": ["serve", "--db", "sqlite", "--dsn", "ccg.db"]
+    },
+    "pgvector": {
+      "command": "npx",
+      "args": ["-y", "mcp-pgvector-server"],
+      "env": {
+        "DATABASE_URL": "postgresql://ccg:ccg@localhost:5455/ccg"
+      }
     }
   }
 }

internal/cli/build.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/imtaebin/code-context-graph/internal/model"
 	"github.com/imtaebin/code-context-graph/internal/parse"
+	"github.com/imtaebin/code-context-graph/internal/store/agestore"
 )
 
 var skipDirs = map[string]bool{
@@ -173,7 +174,7 @@ func newBuildCmd(deps *Deps) *cobra.Command {
 				}
 			}
 
-			// Sync to Apache AGE graph if --graph flag is set
+			// Sync to Apache AGE graph + pgvector if --graph flag is set
 			if syncGraph && deps.AgeStore != nil {
 				deps.Logger.Info("syncing to AGE graph")
 				if err := deps.AgeStore.ClearGraph(ctx); err != nil {
@@ -190,6 +191,30 @@ func newBuildCmd(deps *Deps) *cobra.Command {
 						deps.Logger.Info("AGE graph synced", "nodes", len(indexNodes), "edges", len(edges))
 					}
 				}
+
+				// Sync pgvector documents for semantic search
+				if err := deps.AgeStore.InitPGVector(ctx); err != nil {
+					deps.Logger.Warn("pgvector init failed", "error", err)
+				} else {
+					var pvDocs []agestore.PGVectorDocument
+					for _, n := range indexNodes {
+						pvDocs = append(pvDocs, agestore.PGVectorDocument{
+							NodeID:  n.ID,
+							Content: buildContent(n),
+							Metadata: map[string]string{
+								"qualified_name": n.QualifiedName,
+								"kind":           string(n.Kind),
+								"file_path":      n.FilePath,
+								"language":       n.Language,
+							},
+						})
+					}
+					if err := deps.AgeStore.SyncPGVectorDocuments(ctx, pvDocs); err != nil {
+						deps.Logger.Warn("pgvector sync failed", "error", err)
+					} else {
+						deps.Logger.Info("pgvector documents synced", "documents", len(pvDocs))
+					}
+				}
 			}
 
 			fmt.Fprintf(stdout(cmd), "Build complete: %d files, %d nodes, %d edges\n", totalFiles, totalNodes, totalEdges)

internal/store/agestore/agestore.go

@@ -167,6 +167,56 @@ func (s *Store) ExecuteCypherJSON(ctx context.Context, cypher string, columnCoun
 	return string(b), nil
 }
 
+// InitPGVector creates the pgvector extension and documents table.
+func (s *Store) InitPGVector(ctx context.Context) error {
+	stmts := []string{
+		"CREATE EXTENSION IF NOT EXISTS vector",
+		`CREATE TABLE IF NOT EXISTS ccg_documents (
+			id SERIAL PRIMARY KEY,
+			node_id INTEGER NOT NULL,
+			content TEXT NOT NULL,
+			metadata JSONB,
+			embedding vector(1536),
+			created_at TIMESTAMP DEFAULT NOW()
+		)`,
+		"CREATE INDEX IF NOT EXISTS idx_ccg_documents_node_id ON ccg_documents(node_id)",
+	}
+	for _, stmt := range stmts {
+		if _, err := s.db.ExecContext(ctx, stmt); err != nil {
+			return fmt.Errorf("pgvector init %q: %w", stmt[:40], err)
+		}
+	}
+	return nil
+}
+
+// PGVectorDocument represents a document for pgvector embedding.
+type PGVectorDocument struct {
+	NodeID   uint
+	Content  string
+	Metadata map[string]string
+}
+
+// SyncPGVectorDocuments clears and inserts documents for pgvector embedding.
+func (s *Store) SyncPGVectorDocuments(ctx context.Context, docs []PGVectorDocument) error {
+	// Clear existing documents
+	if _, err := s.db.ExecContext(ctx, "DELETE FROM ccg_documents"); err != nil {
+		return fmt.Errorf("clear pgvector docs: %w", err)
+	}
+
+	// Batch insert
+	for _, d := range docs {
+		metaJSON, _ := json.Marshal(d.Metadata)
+		_, err := s.db.ExecContext(ctx,
+			"INSERT INTO ccg_documents (node_id, content, metadata) VALUES ($1, $2, $3)",
+			d.NodeID, d.Content, string(metaJSON),
+		)
+		if err != nil {
+			return fmt.Errorf("insert pgvector doc node_id=%d: %w", d.NodeID, err)
+		}
+	}
+	return nil
+}
+
 // Close closes the connection.
 func (s *Store) Close() error {
 	return s.db.Close()