diff --git a/internal/store/db.go b/internal/store/db.go
index 33bba10..cf55c7f 100644
--- a/internal/store/db.go
+++ b/internal/store/db.go
@@ -26,11 +26,15 @@ type dbExecer interface {
 
 // DB wraps the SQLite database connection.
 type DB struct {
-	conn *sql.DB
-	tx   *sql.Tx // current active transaction (nil = no transaction)
-	path string
+	conn     *sql.DB
+	tx       *sql.Tx // current active transaction (nil = no transaction)
+	path     string
+	readOnly bool
 }
 
+// IsReadOnly returns true if the database was opened in read-only mode.
+func (db *DB) IsReadOnly() bool { return db.readOnly }
+
 // execer returns the active transaction if set, otherwise the raw connection.
 func (db *DB) execer() dbExecer {
 	if db.tx != nil {
@@ -186,7 +190,7 @@ func OpenReadOnly(dataDir string) (*DB, error) {
 		return nil, fmt.Errorf("open readonly database: %w", err)
 	}
 	conn.SetMaxOpenConns(1)
-	return &DB{conn: conn, path: dbPath}, nil
+	return &DB{conn: conn, path: dbPath, readOnly: true}, nil
 }
 
 // Open opens (or creates) the SQLite database at the given directory.
diff --git a/internal/store/node.go b/internal/store/node.go
index 593afaf..5447430 100644
--- a/internal/store/node.go
+++ b/internal/store/node.go
@@ -135,7 +135,11 @@ func (db *DB) UpdateEntities(id string, entities []string) error {
 }
 
 // IncrementAccessCount bumps the access count and refreshes last_accessed_at.
+// No-op when the database is read-only.
 func (db *DB) IncrementAccessCount(id string) error {
+	if db.readOnly {
+		return nil
+	}
 	_, err := db.execer().Exec(
 		`UPDATE insights SET access_count = access_count + 1, last_accessed_at = ? WHERE id = ?`,
 		time.Now().UTC().Format(time.RFC3339), id)
diff --git a/internal/store/oplog.go b/internal/store/oplog.go
index cecbaea..afc07ac 100644
--- a/internal/store/oplog.go
+++ b/internal/store/oplog.go
@@ -11,7 +11,11 @@ const MaxOplogEntries = 5000
 
 // LogOp records an operation to the oplog and trims old entries beyond MaxOplogEntries.
 // Best-effort: failures are logged to stderr but do not propagate.
+// No-op when the database is read-only.
 func (db *DB) LogOp(operation, insightID, detail string) {
+	if db.readOnly {
+		return
+	}
 	if _, err := db.execer().Exec(
 		`INSERT INTO oplog (operation, insight_id, detail, created_at) VALUES (?, ?, ?, ?)`,
 		operation, insightID, detail, time.Now().UTC().Format(time.RFC3339)); err != nil {