diff --git a/frontend/src/lib/document/documentTypeahead.ts b/frontend/src/lib/document/documentTypeahead.ts
index a5274ad3..1b32fa78 100644
--- a/frontend/src/lib/document/documentTypeahead.ts
+++ b/frontend/src/lib/document/documentTypeahead.ts
@@ -5,10 +5,14 @@ import { getLocale } from '$lib/paraglide/runtime.js';
 
 type DocumentListItem = components['schemas']['DocumentListItem'];
 
-export type DocumentOption = Pick<
-	DocumentListItem,
-	'id' | 'title' | 'documentDate' | 'metaDatePrecision' | 'metaDateEnd'
->;
+/**
+ * Chip/dedup contract for document pickers. `metaDatePrecision`/`metaDateEnd`
+ * are optional: the typeahead always populates them, but a TimelineEvent's
+ * DocumentRef (#781) carries only id/title/documentDate — formatDocumentOption
+ * degrades gracefully (bare title or plain date) when precision is absent.
+ */
+export type DocumentOption = Pick<DocumentListItem, 'id' | 'title' | 'documentDate'> &
+	Partial<Pick<DocumentListItem, 'metaDatePrecision' | 'metaDateEnd'>>;
 
 export function createDocumentTypeahead() {
 	return createTypeahead<DocumentOption>({
diff --git a/frontend/src/routes/zeitstrahl/events/[id]/edit/page.server.spec.ts b/frontend/src/routes/zeitstrahl/events/[id]/edit/page.server.spec.ts
index 8ae60729..652be161 100644
--- a/frontend/src/routes/zeitstrahl/events/[id]/edit/page.server.spec.ts
+++ b/frontend/src/routes/zeitstrahl/events/[id]/edit/page.server.spec.ts
@@ -10,6 +10,9 @@ import { load, actions } from './+page.server';
 
 const mockFetch = vi.fn() as unknown as typeof fetch;
 
+// fail() returns a union type that TS won't narrow; read its data loosely.
+const failData = (r: unknown) => (r as { data: Record<string, unknown> }).data;
+
 beforeEach(() => vi.clearAllMocks());
 
 function localsWith(perms: string[] | null) {
@@ -125,7 +128,7 @@ describe('zeitstrahl/events/[id]/edit save action (REQ-005/013)', () => {
 			actionEvent('save', { title: 'Umzug', type: 'PERSONAL', eventDate: '1925-04-01' })
 		);
 		expect(result).toMatchObject({ status: 409 });
-		expect(result.data.error).toBeTruthy();
+		expect(failData(result).error).toBeTruthy();
 	});
 });
 
@@ -150,6 +153,6 @@ describe('zeitstrahl/events/[id]/edit delete action (REQ-006/007)', () => {
 
 		const result = await actions.delete(actionEvent('delete', {}));
 		expect(result).toMatchObject({ status: 500 });
-		expect(result.data.error).toBeTruthy();
+		expect(failData(result).error).toBeTruthy();
 	});
 });
diff --git a/frontend/src/routes/zeitstrahl/events/new/page.server.spec.ts b/frontend/src/routes/zeitstrahl/events/new/page.server.spec.ts
index accb4ae2..d7aaa331 100644
--- a/frontend/src/routes/zeitstrahl/events/new/page.server.spec.ts
+++ b/frontend/src/routes/zeitstrahl/events/new/page.server.spec.ts
@@ -10,6 +10,9 @@ import { load, actions } from './+page.server';
 
 const mockFetch = vi.fn() as unknown as typeof fetch;
 
+// fail() returns a union type that TS won't narrow; read its data loosely.
+const failData = (r: unknown) => (r as { data: Record<string, unknown> }).data;
+
 beforeEach(() => vi.clearAllMocks());
 
 function localsWith(perms: string[] | null) {
@@ -142,16 +145,16 @@ describe('zeitstrahl/events/new save action (REQ-004/009/010/015)', () => {
 
 		expect(post).not.toHaveBeenCalled();
 		expect(result).toMatchObject({ status: 400 });
-		expect(result.data.personIds).toEqual(['p1', 'p2']);
-		expect(result.data.documentIds).toEqual(['d1']);
-		expect(result.data.titleError).toBeTruthy();
+		expect(failData(result).personIds).toEqual(['p1', 'p2']);
+		expect(failData(result).documentIds).toEqual(['d1']);
+		expect(failData(result).titleError).toBeTruthy();
 	});
 
 	it('surfaces both title and date errors when both blank (REQ-011)', async () => {
 		vi.mocked(createApiClient).mockReturnValue({ POST: vi.fn() } as never);
 		const result = await actions.save(saveEvent({ title: '', type: 'PERSONAL', eventDate: '' }));
-		expect(result.data.titleError).toBeTruthy();
-		expect(result.data.dateError).toBeTruthy();
+		expect(failData(result).titleError).toBeTruthy();
+		expect(failData(result).dateError).toBeTruthy();
 	});
 
 	it('redirects to /persons/{id} when originPersonId is a valid UUID', async () => {
@@ -201,6 +204,6 @@ describe('zeitstrahl/events/new save action (REQ-004/009/010/015)', () => {
 			saveEvent({ title: 'Umzug', type: 'PERSONAL', eventDate: '1925-04-01' })
 		);
 		expect(result).toMatchObject({ status: 409 });
-		expect(result.data.error).toBeTruthy();
+		expect(failData(result).error).toBeTruthy();
 	});
 });