diff --git a/addons/api/mirage/models/account.js b/addons/api/mirage/models/account.js
index 8f39ad219..11c2b3944 100644
--- a/addons/api/mirage/models/account.js
+++ b/addons/api/mirage/models/account.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/auth-method.js b/addons/api/mirage/models/auth-method.js
index 7faa2b5a2..0cc6532df 100644
--- a/addons/api/mirage/models/auth-method.js
+++ b/addons/api/mirage/models/auth-method.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/base.js b/addons/api/mirage/models/base.js
new file mode 100644
index 000000000..dbaa877d9
--- /dev/null
+++ b/addons/api/mirage/models/base.js
@@ -0,0 +1,20 @@
+import { Model } from 'ember-cli-mirage';
+
+export default Model.extend({
+  assignDefaults(defaultAttrs, attrs) {
+    Object.entries(defaultAttrs).map(([key, value]) => {
+      if (!attrs[key]) {
+        attrs[key] = value;
+      }
+    });
+  },
+  defaultAttrs: () => ({
+    version: 1,
+    authorized_actions: ['no-op', 'read', 'update', 'delete'],
+    created_time: new Date(),
+  }),
+  save() {
+    this.assignDefaults(this.defaultAttrs(), this.attrs);
+    return Model.prototype.save.apply(this, arguments);
+  },
+});
diff --git a/addons/api/mirage/models/credential-library.js b/addons/api/mirage/models/credential-library.js
index 921a63182..83ad9f912 100644
--- a/addons/api/mirage/models/credential-library.js
+++ b/addons/api/mirage/models/credential-library.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/credential-store.js b/addons/api/mirage/models/credential-store.js
index 7faa2b5a2..0cc6532df 100644
--- a/addons/api/mirage/models/credential-store.js
+++ b/addons/api/mirage/models/credential-store.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/group.js b/addons/api/mirage/models/group.js
index 67446a6d6..17a62f13e 100644
--- a/addons/api/mirage/models/group.js
+++ b/addons/api/mirage/models/group.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo, hasMany } from 'ember-cli-mirage';
+import { belongsTo, hasMany } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/host-catalog.js b/addons/api/mirage/models/host-catalog.js
index 0f03cb6ef..a898eb0c0 100644
--- a/addons/api/mirage/models/host-catalog.js
+++ b/addons/api/mirage/models/host-catalog.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo, hasMany } from 'ember-cli-mirage';
+import { belongsTo, hasMany } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/host-set.js b/addons/api/mirage/models/host-set.js
index 645c144ff..58f32181f 100644
--- a/addons/api/mirage/models/host-set.js
+++ b/addons/api/mirage/models/host-set.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo, hasMany } from 'ember-cli-mirage';
+import { belongsTo, hasMany } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/host.js b/addons/api/mirage/models/host.js
index 88d9026e8..bd7e561df 100644
--- a/addons/api/mirage/models/host.js
+++ b/addons/api/mirage/models/host.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/managed-group.js b/addons/api/mirage/models/managed-group.js
index 8f39ad219..11c2b3944 100644
--- a/addons/api/mirage/models/managed-group.js
+++ b/addons/api/mirage/models/managed-group.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/role.js b/addons/api/mirage/models/role.js
index c256df5fc..97be034f9 100644
--- a/addons/api/mirage/models/role.js
+++ b/addons/api/mirage/models/role.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo, hasMany } from 'ember-cli-mirage';
+import { belongsTo, hasMany } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/session.js b/addons/api/mirage/models/session.js
index eb036d6b8..4842c2480 100644
--- a/addons/api/mirage/models/session.js
+++ b/addons/api/mirage/models/session.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo } from 'ember-cli-mirage';
+import { belongsTo } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/target.js b/addons/api/mirage/models/target.js
index 389e255d2..d6a7b8ab0 100644
--- a/addons/api/mirage/models/target.js
+++ b/addons/api/mirage/models/target.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo, hasMany } from 'ember-cli-mirage';
+import Model from './base';
+import { belongsTo, hasMany } from 'ember-cli-mirage';
 
 export default Model.extend({
   scope: belongsTo(),
diff --git a/addons/api/mirage/models/user.js b/addons/api/mirage/models/user.js
index d3eb79bed..984a681b8 100644
--- a/addons/api/mirage/models/user.js
+++ b/addons/api/mirage/models/user.js
@@ -1,4 +1,5 @@
-import { Model, belongsTo, hasMany } from 'ember-cli-mirage';
+import { belongsTo, hasMany } from 'ember-cli-mirage';
+import Model from './base';
 
 export default Model.extend({
   scope: belongsTo(),