diff --git a/internal/directives/promotions.go b/internal/directives/promotions.go
index dc26adaf0..fda35fe12 100644
--- a/internal/directives/promotions.go
+++ b/internal/directives/promotions.go
@@ -15,6 +15,7 @@ import (
 	"github.com/akuity/kargo/internal/controller/freight"
 	"github.com/akuity/kargo/internal/credentials"
 	"github.com/akuity/kargo/internal/expressions"
+	"github.com/akuity/kargo/internal/kargo"
 )
 
 // PromotionStepRunner is an interface for components that implement the logic for
@@ -472,7 +473,7 @@ func getChartFunc(
 // The namespace part is the part before the first "::" separator. Typically,
 // this is used for steps inflated from a task.
 func getAliasNamespace(alias string) string {
-	parts := strings.Split(alias, "::")
+	parts := strings.Split(alias, kargo.PromotionAliasSeparator)
 	if len(parts) != 2 {
 		return ""
 	}
diff --git a/internal/directives/simple_engine.go b/internal/directives/simple_engine.go
index b56a0871f..80c58862a 100644
--- a/internal/directives/simple_engine.go
+++ b/internal/directives/simple_engine.go
@@ -10,7 +10,7 @@ import (
 
 // ReservedStepAliasRegex is a regular expression that matches step aliases that
 // are reserved for internal use.
-var ReservedStepAliasRegex = regexp.MustCompile(`^step-\d+$`)
+var ReservedStepAliasRegex = regexp.MustCompile(`^(step|task)-\d+$`)
 
 // SimpleEngine is a simple engine that executes a list of PromotionSteps in
 // sequence.
diff --git a/internal/kargo/promotion_builder.go b/internal/kargo/promotion_builder.go
index ff3386fc4..3513b42c0 100644
--- a/internal/kargo/promotion_builder.go
+++ b/internal/kargo/promotion_builder.go
@@ -15,13 +15,13 @@ import (
 )
 
 const (
+	// PromotionAliasSeparator is the separator used in the Promotion step alias
+	// to separate the task alias from the step alias.
+	PromotionAliasSeparator = "::"
+
 	// nameSeparator is the separator used in the Promotion name.
 	nameSeparator = "."
 
-	// aliasSeparator is the separator used in the Promotion step alias
-	// to separate the task alias from the step alias.
-	aliasSeparator = "::"
-
 	// ulidLength is the length of the ULID string.
 	ulidLength = ulid.EncodedSize
 
@@ -217,7 +217,7 @@ func generatePromotionName(stageName, freight string) string {
 // generatePromotionTaskStepAlias generates an alias for a PromotionTask step
 // by combining the task alias and the step alias.
 func generatePromotionTaskStepAlias(taskAlias, stepAlias string) string {
-	return fmt.Sprintf("%s%s%s", taskAlias, aliasSeparator, stepAlias)
+	return fmt.Sprintf("%s%s%s", taskAlias, PromotionAliasSeparator, stepAlias)
 }
 
 // promotionTaskVarsToStepVars validates the presence of the PromotionTask