diff --git a/pkg/agent/context.go b/pkg/agent/context.go
index 667d714a5..e0f460f19 100644
--- a/pkg/agent/context.go
+++ b/pkg/agent/context.go
@@ -927,14 +927,10 @@ func messageThreadAnnotationBody(msg providers.Message) string {
 		formattedIDs = "#" + formattedIDs
 	}
 	switch {
-	case len(msgIDs) > 1 && msg.ReplyToMessageID != "":
+	case len(msgIDs) > 0 && msg.ReplyToMessageID != "":
 		return fmt.Sprintf("msgs:%s, reply_to:#%s", formattedIDs, msg.ReplyToMessageID)
-	case len(msgIDs) > 1:
+	case len(msgIDs) > 0:
 		return fmt.Sprintf("msgs:%s", formattedIDs)
-	case len(msgIDs) == 1 && msg.ReplyToMessageID != "":
-		return fmt.Sprintf("msg:%s, reply_to:#%s", formattedIDs, msg.ReplyToMessageID)
-	case len(msgIDs) == 1:
-		return fmt.Sprintf("msg:%s", formattedIDs)
 	case msg.ReplyToMessageID != "":
 		return fmt.Sprintf("reply_to:#%s", msg.ReplyToMessageID)
 	default:
diff --git a/pkg/agent/context_test.go b/pkg/agent/context_test.go
index 6a6ec24b2..08cec97b8 100644
--- a/pkg/agent/context_test.go
+++ b/pkg/agent/context_test.go
@@ -226,7 +226,7 @@ func TestMessageHistoryAnnotation_IncludesSenderAndThreading(t *testing.T) {
 		},
 	}
 
-	if got := messageHistoryAnnotation(msg); got != "[from:Alice Example (@alice), msg:#m1, reply_to:#p0] " {
+	if got := messageHistoryAnnotation(msg); got != "[from:Alice Example (@alice), msgs:#m1, reply_to:#p0] " {
 		t.Fatalf("messageHistoryAnnotation() = %q", got)
 	}
 }