diff --git a/backend/src/modules/note-collaborators/routes.test.ts b/backend/src/modules/note-collaborators/routes.test.ts
index 86632cd..4c1d8da 100644
--- a/backend/src/modules/note-collaborators/routes.test.ts
+++ b/backend/src/modules/note-collaborators/routes.test.ts
@@ -14,22 +14,25 @@ vi.mock('../../lib/embeddings.js', () => ({
   stripHtmlForEmbedding: vi.fn((s: string) => s.replace(/<[^>]*>/g, ' ').trim()),
 }));
 
-const getNoteMock = vi.fn(async () => null);
+type NoteDoc = { id: string; userId?: string; productId?: string; title?: string; body?: string };
+type CollabDoc = Record<string, unknown>;
+
+const getNoteMock = vi.fn<(id: string, userId: string) => Promise<NoteDoc | null>>();
 vi.mock('../notes/repository.js', () => ({
-  getNote: (...args: unknown[]) => getNoteMock(...args),
+  getNote: (...args: [string, string]) => getNoteMock(...args),
 }));
 
-const createCollaboratorMock = vi.fn(async (doc: Record<string, unknown>) => doc);
-const listCollaboratorsForNoteMock = vi.fn(async () => []);
-const listSharedWithMeMock = vi.fn(async () => []);
-const findCollaboratorMock = vi.fn(async () => null);
-const deleteCollaboratorMock = vi.fn(async () => undefined);
+const createCollaboratorMock = vi.fn<(doc: CollabDoc) => Promise<CollabDoc>>();
+const listCollaboratorsForNoteMock = vi.fn<(noteId: string, productId: string) => Promise<CollabDoc[]>>();
+const listSharedWithMeMock = vi.fn<(userId: string, productId: string) => Promise<CollabDoc[]>>();
+const findCollaboratorMock = vi.fn<(noteId: string, userId: string, productId: string) => Promise<CollabDoc | null>>();
+const deleteCollaboratorMock = vi.fn<(id: string, partitionKey: string) => Promise<void>>();
 vi.mock('./repository.js', () => ({
-  createCollaborator: (...args: unknown[]) => createCollaboratorMock(...args as [Record<string, unknown>]),
-  listCollaboratorsForNote: (...args: unknown[]) => listCollaboratorsForNoteMock(...args),
-  listSharedWithMe: (...args: unknown[]) => listSharedWithMeMock(...args),
-  findCollaborator: (...args: unknown[]) => findCollaboratorMock(...args),
-  deleteCollaborator: (...args: unknown[]) => deleteCollaboratorMock(...args),
+  createCollaborator: (...args: [CollabDoc]) => createCollaboratorMock(...args),
+  listCollaboratorsForNote: (...args: [string, string]) => listCollaboratorsForNoteMock(...args),
+  listSharedWithMe: (...args: [string, string]) => listSharedWithMeMock(...args),
+  findCollaborator: (...args: [string, string, string]) => findCollaboratorMock(...args),
+  deleteCollaborator: (...args: [string, string]) => deleteCollaboratorMock(...args),
 }));
 
 import { buildTestApp } from '../../test-helpers.js';