diff --git a/Sources/Containerization/Image/ImageStore/ImageStore+Import.swift b/Sources/Containerization/Image/ImageStore/ImageStore+Import.swift
index 730e5779..7dc4eb4a 100644
--- a/Sources/Containerization/Image/ImageStore/ImageStore+Import.swift
+++ b/Sources/Containerization/Image/ImageStore/ImageStore+Import.swift
@@ -211,7 +211,12 @@ extension ImageStore {
                 let platform = supportedPlatforms.first!
                 var root = root
                 root.platform = platform
-                let index = ContainerizationOCI.Index(schemaVersion: 2, manifests: [root])
+                let index = ContainerizationOCI.Index(
+                    schemaVersion: 2, manifests: [root],
+                    annotations: [
+                        // indicate that this is a synthesized index which is not directly user facing
+                        AnnotationKeys.containerizationIndexIndirect: "true"
+                    ])
                 return index
             default:
                 throw ContainerizationError(.internalError, message: "Failed to create index for descriptor \(root.digest), media type \(root.mediaType)")
diff --git a/Sources/ContainerizationOCI/AnnotationKeys.swift b/Sources/ContainerizationOCI/AnnotationKeys.swift
index d20b6fc7..de8d9df2 100644
--- a/Sources/ContainerizationOCI/AnnotationKeys.swift
+++ b/Sources/ContainerizationOCI/AnnotationKeys.swift
@@ -17,6 +17,7 @@
 /// AnnotationKeys contains a subset of "dictionary keys" for commonly used annotations in an OCI Image Descriptor
 /// https://github.com/opencontainers/image-spec/blob/main/annotations.md
 public struct AnnotationKeys: Codable, Sendable {
+    public static let containerizationIndexIndirect = "com.apple.containerization.index.indirect"
     public static let containerizationImageName = "com.apple.containerization.image.name"
     public static let containerdImageName = "io.containerd.image.name"
     public static let openContainersImageName = "org.opencontainers.image.ref.name"