diff --git a/go/nix/nixstore/remotestore.go b/go/nix/nixstore/remotestore.go
index 85bed91f86..c5a69b0eb2 100644
--- a/go/nix/nixstore/remotestore.go
+++ b/go/nix/nixstore/remotestore.go
@@ -7,6 +7,7 @@ import (
 	"net"
 	"path"
 	"strings"
+	"sync"
 
 	"hg.lukegb.com/lukegb/depot/go/nix/nar/narinfo"
 	"hg.lukegb.com/lukegb/depot/go/nix/nixwire"
@@ -26,9 +27,14 @@ type Daemon struct {
 	conn net.Conn
 	w    *nixwire.Serializer
 	r    *nixwire.Deserializer
+	mu   sync.Mutex
+	err  error
 }
 
 func (d *Daemon) NARInfo(storePath string) (*narinfo.NarInfo, error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
 	if _, err := d.w.WriteUint64(WopQueryPathInfo); err != nil {
 		return nil, fmt.Errorf("writing worker op WopQueryPathInfo: %w", err)
 	}
@@ -104,6 +110,9 @@ func (d *Daemon) NARInfo(storePath string) (*narinfo.NarInfo, error) {
 }
 
 func (d *Daemon) Close() error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
 	return d.conn.Close()
 }