diff --git a/terraform/platform/monitoring/main.tf b/terraform/platform/monitoring/main.tf
index 67cb555..18498b0 100644
--- a/terraform/platform/monitoring/main.tf
+++ b/terraform/platform/monitoring/main.tf
@@ -505,11 +505,11 @@ resource "aws_dynamodb_table" "alert_dedup" {
 
 # Cost allocation tags must exist on at least one billed resource before
 # activation. Tags are added in phases:
-#   Phase 1 (now): team, service, environment, managed-by — already on resources
-#   Phase 2 (after first apply with new tags): repo
+#   Phase 1: team, service, environment, managed-by
+#   Phase 2: repo (in default_tags, now on resources)
 #   Phase 3 (after resource-tagger runs): created-by, commit
 resource "aws_ce_cost_allocation_tag" "tags" {
-  for_each = toset(["team", "service", "environment", "managed-by"])
+  for_each = toset(["team", "service", "environment", "managed-by", "repo"])
   tag_key  = each.key
   status   = "Active"
 }