diff --git a/src/models/collection.ts b/src/models/collection.ts
index f5ac01b..a84857b 100644
--- a/src/models/collection.ts
+++ b/src/models/collection.ts
@@ -2,9 +2,17 @@
  * Class model for Collection Interface
  */
 
-import type { CollectionInterface, CollectionModelInterface, CollectionPropertiesInterface, CollectionPropertiesModelInterface } from "@/types/collection";
+import type {
+    CollectionInterface,
+    CollectionModelInterface,
+    CollectionPropertiesInterface,
+    CollectionPropertiesModelInterface
+} from "@/types/collection";
 import { clonePlain } from './clone-plain';
-import type { CollectionIdentifier, ServiceIdentifier } from "@/services";
+import type {
+    CollectionIdentifier,
+    ServiceIdentifier
+} from "@/services";
 
 export class CollectionObject implements CollectionModelInterface {
 
@@ -16,9 +24,9 @@ export class CollectionObject implements CollectionModelInterface {
             '@type': 'mail:collection',
             version: 1,
             provider: '',
-            service: '',
-            collection: null,
-            identifier: '',
+            service: '' as ServiceIdentifier,
+            collection: null as CollectionIdentifier | null,
+            identifier: '' as CollectionIdentifier,
             properties: {'@type': 'mail:folder', label: ''},
         };
     }
diff --git a/src/models/entity.ts b/src/models/entity.ts
index d569d0e..0ba4cf8 100644
--- a/src/models/entity.ts
+++ b/src/models/entity.ts
@@ -19,8 +19,8 @@ export class EntityObject implements EntityModelInterface {
             version: 1,
             provider: '',
             service: '',
-            collection: null,
-            identifier: null,
+            collection: '' as CollectionIdentifier,
+            identifier: '' as EntityIdentifier,
             signature: null,
             created: null,
             modified: null,
diff --git a/src/stores/entitiesStore.ts b/src/stores/entitiesStore.ts
index e78f9e2..3aa466e 100644
--- a/src/stores/entitiesStore.ts
+++ b/src/stores/entitiesStore.ts
@@ -44,13 +44,10 @@ export const useEntitiesStore = defineStore('mailEntitiesStore', () => {
 
   /**
    * Get a specific entity from store, with optional retrieval
-   * 
-   * @param provider - provider identifier
-   * @param service - service identifier
-   * @param collection - collection identifier
-   * @param identifier - entity identifier
+   *
+   * @param target - entity identifier
    * @param retrieve - Retrieve behavior: true = fetch if missing or refresh, false = cache only
-   * 
+   *
    * @returns Entity object or null
    */
   function entity(target: EntityIdentifier, retrieve: boolean = false): EntityObject | null {
@@ -64,12 +61,10 @@ export const useEntitiesStore = defineStore('mailEntitiesStore', () => {
 
   /**
    * Get all entities for a specific collection
-   * 
-   * @param provider - provider identifier
-   * @param service - service identifier
-   * @param collection - collection identifier
+   *
+   * @param target - collection identifier
    * @param retrieve - Retrieve behavior: true = fetch if missing or refresh, false = cache only
-   * 
+   *
    * @returns Array of entity objects
    */
   function entitiesForCollection(target: CollectionIdentifier, retrieve: boolean = false): EntityObject[] {
@@ -117,14 +112,11 @@ export const useEntitiesStore = defineStore('mailEntitiesStore', () => {
     }
   }
   
-  /**
-   * Retrieve specific entities by provider, service, collection, and identifiers
-   * 
-   * @param provider - provider identifier
-   * @param service - service identifier
-   * @param collection - collection identifier
-   * @param identifiers - array of entity identifiers to fetch
-   * 
+    /**
+   * Retrieve specific entities by their identifiers
+   *
+   * @param targets - array of entity identifiers to fetch
+   *
    * @returns Promise with entity objects keyed by identifier
    */
   async function fetch(targets: EntityIdentifier[]): Promise<Record<string, EntityObject>> {
diff --git a/src/types/collection.ts b/src/types/collection.ts
index 5b84dbe..dc58834 100644
--- a/src/types/collection.ts
+++ b/src/types/collection.ts
@@ -1,7 +1,12 @@
 /**
  * Collection type definitions
  */
-import type { CollectionIdentifier, ListFilter, ListSort, ServiceIdentifier } from './common';
+import type {
+  ServiceIdentifier,
+  CollectionIdentifier,
+  ListFilter,
+  ListSort
+} from './common';
 
 /**
  * Collection information
diff --git a/src/types/entity.ts b/src/types/entity.ts
index 3cdadd7..0a85f99 100644
--- a/src/types/entity.ts
+++ b/src/types/entity.ts
@@ -8,7 +8,10 @@ import type {
   ListRange,
   ListSort,
 } from './common';
-import type { MessageInterface, MessageModelInterface } from './message';
+import type {
+  MessageInterface,
+  MessageModelInterface
+} from './message';
 
 /**
  * Entity definition
diff --git a/src/types/provider.ts b/src/types/provider.ts
index 60e0b30..dbc0130 100644
--- a/src/types/provider.ts
+++ b/src/types/provider.ts
@@ -39,14 +39,14 @@ export interface ProviderListRequest {
 }
 
 export interface ProviderListResponse {
-  [identifier: string]: ProviderInterface;
+  [identifier: ProviderIdentifier]: ProviderInterface;
 }
 
 /**
  * Provider fetch 
  */
 export interface ProviderFetchRequest {
-  target: string;
+  target: ProviderIdentifier;
 }
 
 export interface ProviderFetchResponse extends ProviderInterface {}
@@ -59,5 +59,5 @@ export interface ProviderExtantRequest {
 }
 
 export interface ProviderExtantResponse {
-  [identifier: string]: boolean;
+  [identifier: ProviderIdentifier]: boolean;
 }
diff --git a/src/types/service.ts b/src/types/service.ts
index f7f3148..22aa2c9 100644
--- a/src/types/service.ts
+++ b/src/types/service.ts
@@ -5,9 +5,9 @@ import type { ServiceAddressObject } from '@/models/address';
 import type { Identity } from '@/models/identity';
 import type { Location } from '@/models/location';
 import type {
+  ServiceIdentifier,
   CollectionIdentifier,
   ListFilterComparisonOperator,
-  ServiceIdentifier,
 } from './common';
 
 /**