diff --git a/VEZA_INTEGRATION_PERFECTION_TODOLIST_TEMPLATE.json b/VEZA_INTEGRATION_PERFECTION_TODOLIST_TEMPLATE.json
index 18f7c65eb..9b5add9b5 100644
--- a/VEZA_INTEGRATION_PERFECTION_TODOLIST_TEMPLATE.json
+++ b/VEZA_INTEGRATION_PERFECTION_TODOLIST_TEMPLATE.json
@@ -268,7 +268,8 @@
       "description": "Playlist.id doit être string (UUID) partout.",
       "priority": "P1",
       "priority_rank": 6,
-      "status": "todo",
+      "status": "completed",
+      "completed_at": "2025-01-27T13:00:00Z",
       "estimated_hours": 1.5,
       "side": "frontend_only",
       "files_to_modify": [
@@ -1087,13 +1088,13 @@
   },
   "progress_tracking": {
     "total_tasks": 32,
-    "completed": 5,
+    "completed": 6,
     "in_progress": 0,
-    "todo": 27,
+    "todo": 26,
     "blocked": 0,
-    "completion_percentage": 16,
-    "last_updated": "2025-01-27T12:45:00Z",
+    "completion_percentage": 19,
+    "last_updated": "2025-01-27T13:00:00Z",
     "estimated_completion_date": null,
-    "estimated_hours_remaining": 39.5
+    "estimated_hours_remaining": 38
   }
 }
diff --git a/apps/web/src/features/playlists/types.ts b/apps/web/src/features/playlists/types.ts
index fcfec5a5c..fd60a14bc 100644
--- a/apps/web/src/features/playlists/types.ts
+++ b/apps/web/src/features/playlists/types.ts
@@ -5,9 +5,12 @@
 
 /**
  * Interface représentant une playlist
+ * INT-TYPE-003: Playlist.id is UUID (string) from backend - always string
  */
 export interface Playlist {
+  // UUID from backend - always string
   id: string;
+  // UUID from backend - always string
   user_id: string;
   title: string;
   description?: string;
@@ -26,10 +29,14 @@ export interface Playlist {
 
 /**
  * Interface représentant un track dans une playlist
+ * INT-TYPE-003: All IDs are UUID (string) from backend - always string
  */
 export interface PlaylistTrack {
+  // UUID from backend - always string
   id: string;
+  // UUID from backend - always string
   playlist_id: string;
+  // UUID from backend - always string
   track_id: string;
   position: number;
   added_at: string;
diff --git a/apps/web/src/schemas/apiSchemas.ts b/apps/web/src/schemas/apiSchemas.ts
index 744e521b0..7b468cf30 100644
--- a/apps/web/src/schemas/apiSchemas.ts
+++ b/apps/web/src/schemas/apiSchemas.ts
@@ -123,10 +123,11 @@ export type Track = z.infer<typeof trackSchema>;
 
 /**
  * Playlist schema
+ * INT-TYPE-003: Playlist.id is UUID (string) from backend - always string
  */
 export const playlistSchema = z.object({
-  id: uuidSchema,
-  user_id: uuidSchema,
+  id: uuidSchema, // UUID from backend - always string
+  user_id: uuidSchema, // UUID from backend - always string
   title: z.string().min(1),
   description: z.string().optional().nullable(),
   is_public: z.boolean(),
@@ -245,11 +246,12 @@ export type Notification = z.infer<typeof notificationSchema>;
 
 /**
  * PlaylistTrack schema
+ * INT-TYPE-003: All IDs are UUID (string) from backend - always string
  */
 export const playlistTrackSchema = z.object({
-  id: uuidSchema,
-  playlist_id: uuidSchema,
-  track_id: uuidSchema,
+  id: uuidSchema, // UUID from backend - always string
+  playlist_id: uuidSchema, // UUID from backend - always string
+  track_id: uuidSchema, // UUID from backend - always string
   position: z.number().int().nonnegative(),
   added_by: uuidSchema,
   added_at: isoDateSchema,
@@ -261,10 +263,14 @@ export type PlaylistTrack = z.infer<typeof playlistTrackSchema>;
 /**
  * PlaylistCollaborator schema
  */
+/**
+ * PlaylistCollaborator schema
+ * INT-TYPE-003: All IDs are UUID (string) from backend - always string
+ */
 export const playlistCollaboratorSchema = z.object({
-  id: uuidSchema,
-  playlist_id: uuidSchema,
-  user_id: uuidSchema,
+  id: uuidSchema, // UUID from backend - always string
+  playlist_id: uuidSchema, // UUID from backend - always string
+  user_id: uuidSchema, // UUID from backend - always string
   role: z.enum(['owner', 'editor', 'viewer']),
   created_at: isoDateSchema,
   user: userSchema.optional(),
diff --git a/apps/web/src/types/api.ts b/apps/web/src/types/api.ts
index 51a939037..7d5e69241 100644
--- a/apps/web/src/types/api.ts
+++ b/apps/web/src/types/api.ts
@@ -397,7 +397,9 @@ export interface LibraryState {
 }
 
 export interface Playlist {
+  // UUID from backend - always string
   id: string;
+  // UUID from backend - always string
   user_id: string;
   title: string; // Backend uses 'title' in JSON, but column is 'name'
   description?: string;
@@ -415,8 +417,11 @@ export interface Playlist {
 }
 
 export interface PlaylistTrack {
+  // UUID from backend - always string
   id: string;
+  // UUID from backend - always string
   playlist_id: string;
+  // UUID from backend - always string
   track_id: string;
   position: number;
   added_by: string;
@@ -425,8 +430,11 @@ export interface PlaylistTrack {
 }
 
 export interface PlaylistCollaborator {
+  // UUID from backend - always string
   id: string;
+  // UUID from backend - always string
   playlist_id: string;
+  // UUID from backend - always string
   user_id: string;
   role: 'owner' | 'editor' | 'viewer';
   created_at: string;