diff --git a/nullplatform/scope_definition/data.tf b/nullplatform/scope_definition/data.tf
index d2586e5bb..d72d4fee0 100644
--- a/nullplatform/scope_definition/data.tf
+++ b/nullplatform/scope_definition/data.tf
@@ -10,7 +10,7 @@ data "http" "scope_type_template" {
 }
 
 data "http" "action_templates" {
-  for_each = toset(var.action_spec_names)
+  for_each = local.static_action_specs
   url      = "${var.repository_action_templates}/${var.repository_action_templates_branch}/${var.service_path}/specs/actions/${each.key}.json.tpl"
 }
 
@@ -63,7 +63,7 @@ data "external" "scope_type" {
 # it forces a phantom destroy+recreate of EVERY action_specification
 # instance at once (their `type` is ForceNew).
 data "external" "action_specs" {
-  for_each = toset(var.action_spec_names)
+  for_each = local.static_action_specs
   depends_on = [
     data.http.action_templates
   ]
diff --git a/nullplatform/scope_definition/locals.tf b/nullplatform/scope_definition/locals.tf
index fd3292bf5..468c71374 100644
--- a/nullplatform/scope_definition/locals.tf
+++ b/nullplatform/scope_definition/locals.tf
@@ -15,7 +15,9 @@ locals {
 
   scope_type_def = jsondecode(data.external.scope_type.result.json)
 
-  static_action_specs = toset(var.action_spec_names)
+  static_action_specs = toset(
+    var.action_spec_names != null ? var.action_spec_names : try(local.service_spec_parsed.available_actions, [])
+  )
 
   scope_configuration_rendered = var.create_scope_configuration ? replace(
     data.http.scope_configuration_template[0].response_body,
diff --git a/nullplatform/scope_definition/main.tf b/nullplatform/scope_definition/main.tf
index 2c41801d6..078724b72 100644
--- a/nullplatform/scope_definition/main.tf
+++ b/nullplatform/scope_definition/main.tf
@@ -22,6 +22,29 @@ resource "nullplatform_service_specification" "from_template" {
     provider     = local.service_spec_parsed.selectors.provider
     sub_category = local.service_spec_parsed.selectors.sub_category
   }
+
+  # Resolving to no actions means the caller relied on the default this variable
+  # no longer has, and its spec predates `available_actions`. Left alone that is
+  # an empty for_each below, which destroys every action specification the scope
+  # has registered — silently, since an empty list is not an error.
+  #
+  # The check lives here and not on the action_specification resource: with an
+  # empty for_each that resource has no instances, so its preconditions never run.
+  lifecycle {
+    precondition {
+      condition     = length(local.static_action_specs) > 0
+      error_message = <<-EOT
+        No actions resolved for scope "${var.service_spec_name}".
+
+        Declare `available_actions` in ${var.service_path}/specs/service-spec.json.tpl,
+        or pass `action_spec_names` explicitly.
+
+        Proceeding would destroy every action specification registered for this
+        scope: creating and deleting scopes, deploying, blue/green, rollback and
+        diagnostics all stop being available from the UI.
+      EOT
+    }
+  }
 }
 
 ################################################################################
diff --git a/nullplatform/scope_definition/variables.tf b/nullplatform/scope_definition/variables.tf
index 4d2ec94f9..3ce1eaff7 100644
--- a/nullplatform/scope_definition/variables.tf
+++ b/nullplatform/scope_definition/variables.tf
@@ -58,25 +58,15 @@ variable "repo_path" {
 }
 
 variable "action_spec_names" {
-  description = "List of action specification template names to fetch and create for scope operations"
+  description = <<-EOT
+    List of action specification template names to fetch and create for scope
+    operations. Default `null` -> use the `available_actions` array from the
+    scope's `service-spec.json.tpl` (fetched via `repository_service_spec` /
+    `service_path`). Set this explicitly only when the spec's list is wrong
+    for your case or the spec predates the `available_actions` field.
+  EOT
   type        = list(string)
-  default = [
-    "create-scope",
-    "delete-scope",
-    "start-initial",
-    "start-blue-green",
-    "finalize-blue-green",
-    "rollback-deployment",
-    "delete-deployment",
-    "switch-traffic",
-    "set-desired-instance-count",
-    "pause-autoscaling",
-    "resume-autoscaling",
-    "restart-pods",
-    "kill-instances",
-    "diagnose-deployment",
-    "diagnose-scope"
-  ]
+  default     = null
 }
 
 ################################################################################