diff --git a/addMutex.go b/addMutex.go
index 1b1db0c..5e374f8 100644
--- a/addMutex.go
+++ b/addMutex.go
@@ -39,7 +39,7 @@ func (pb *Files) addMutex(f *File) error {
 			start := "type " + msg.Name + " struct {"
 			// marshalThing(w, msg.Name)
 			// log.Info("line:", line)
-			if strings.HasSuffix(line, start) {
+			if strings.HasPrefix(line, start) {
 				msg.MutexFound = true
 				found = true
 				if argv.Mutex {
@@ -53,6 +53,8 @@ func (pb *Files) addMutex(f *File) error {
 					fmt.Fprintln(w, "\t// Lock sync.RWMutex // autogenpb skipped this. needs --mutex command line arg")
 					fmt.Fprintln(w, "")
 				}
+				// important to exit here. somehow this matched twice at one point. notsure how
+				break
 			}
 		}
 		if !found {
diff --git a/argv.go b/argv.go
index 7357f6b..676e67e 100644
--- a/argv.go
+++ b/argv.go
@@ -9,13 +9,14 @@ package main
 var argv args
 
 type args struct {
-	Package string `arg:"--package"                 help:"the package name"`
-	Proto   string `arg:"--proto"                   help:"the .proto filename"`
-	Mutex   bool   `arg:"--mutex"  default:"true"   help:"insert a mutex into protoc .pb.go file"`
-	Delete  bool   `arg:"--delete"                  help:"use delete with copy experiment"`
-	DryRun  bool   `arg:"--dry-run"                 help:"show what would be run"`
-	GoSrc   string `arg:"--go-src"                  help:"default is ~/go/src. could be set to your go.work path"`
-	GoPath  string `arg:"--gopath"                  help:"the gopath of this repo"`
+	Package  string `arg:"--package"                 help:"the package name"`
+	Proto    string `arg:"--proto"                   help:"the .proto filename"`
+	Mutex    bool   `arg:"--mutex"  default:"true"   help:"insert a mutex into protoc .pb.go file"`
+	Delete   bool   `arg:"--delete"                  help:"use delete with copy experiment"`
+	DryRun   bool   `arg:"--dry-run"                 help:"show what would be run"`
+	GoSrc    string `arg:"--go-src"                  help:"default is ~/go/src. could be set to your go.work path"`
+	GoPath   string `arg:"--gopath"                  help:"the gopath of this repo"`
+	Identify string `arg:"--identify"                help:"identify file"`
 }
 
 func (a args) Description() string {