diff --git a/apps/web/src/lib/stores/lists.ts b/apps/web/src/lib/stores/lists.ts
index 4a1b1d3..a8a7881 100644
--- a/apps/web/src/lib/stores/lists.ts
+++ b/apps/web/src/lib/stores/lists.ts
@@ -287,6 +287,13 @@ export async function reorderItems(items: Pick<ShoppingItem, 'id'>[]) {
  * `(...)` list as a SQL error, and the cost of adding the filter for zero
  * effect would be wasted bytes on the URL anyway.
  *
+ * Long-list caveat: PostgREST encodes `not.in.(a,b,…)` literally in the
+ * query string, and supabase-js sends it as a single GET. Some upstream
+ * proxies / Kong configs cap request URI length around 16 KiB. We hard-cap
+ * the exclude list at EXCLUDE_NAMES_HARD_CAP names — past that point the
+ * filter degrades to a no-op (the dropdown may show a few names that are
+ * already on the list; acceptable UX) instead of failing the whole query.
+ *
  * `limit` overrides the default (5 without prefix, 10 with). The /collective
  * manage view does not call this — it has its own unbounded list query in
  * commonItems.ts — but UI experimentation may want a smaller bar.
@@ -296,6 +303,8 @@ export interface FetchSuggestionsOptions {
 	limit?: number;
 }
 
+const EXCLUDE_NAMES_HARD_CAP = 200;
+
 export async function fetchSuggestions(
 	collectiveId: string,
 	prefix: string,
@@ -317,7 +326,7 @@ export async function fetchSuggestions(
 		.map((n) => n.toLowerCase().trim())
 		.filter((n) => n.length > 0);
 
-	if (exclude.length > 0) {
+	if (exclude.length > 0 && exclude.length <= EXCLUDE_NAMES_HARD_CAP) {
 		// PostgREST in() takes a comma-separated list wrapped in parens. We
 		// double-quote each entry to be safe against names containing commas
 		// or parens (e.g. "rice (white)"); the inner double quotes are escaped
diff --git a/apps/web/tests/e2e/items.test.ts b/apps/web/tests/e2e/items.test.ts
index a1b6bea..d691565 100644
--- a/apps/web/tests/e2e/items.test.ts
+++ b/apps/web/tests/e2e/items.test.ts
@@ -102,19 +102,55 @@ test.describe('Shopping items — member (Borja)', () => {
 	});
 
 	test('D-06: frequency suggestions render below the add-item input', async ({ page }) => {
-		await gotoSeedList(page);
-		const nameInput = page.getByPlaceholder(ADD_ITEM_PLACEHOLDER);
-		await expect(nameInput).toBeVisible({ timeout: 10_000 });
+		// Use a fresh empty list. The seed list is shared mutable state for
+		// the entire suite — it accumulates many items over a long run, and
+		// the Fase-15 exclude-on-list filter then suppresses every frequency
+		// name that happens to match one of those items. A fresh empty list
+		// keeps the suggestion strip's contents deterministic.
+		const listId = await page.evaluate(async () => {
+			const supabase = (
+				window as unknown as { __sb: import('@supabase/supabase-js').SupabaseClient }
+			).__sb;
+			const { data } = await supabase
+				.from('shopping_lists')
+				.insert({
+					collective_id: 'aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa',
+					name: `d-06 list ${Date.now()}`,
+					created_by: '22222222-2222-2222-2222-222222222222'
+				})
+				.select('id')
+				.single();
+			return data?.id ?? '';
+		});
 
-		// Focus the input. The seed data has "milk", "bread", "eggs", etc. in
-		// item_frequency, so suggestion chips should render.
-		await nameInput.click();
-		// At least one of the seed-frequency items should be visible as a chip.
-		await expect(page.getByRole('button', { name: /^milk$/i })).toBeVisible({ timeout: 5_000 });
+		try {
+			await page.goto(`/lists/${listId}`);
+			await expect(page.getByRole('button', { name: /Casa García-López/ })).toBeVisible({
+				timeout: 15_000
+			});
+			const nameInput = page.getByPlaceholder(ADD_ITEM_PLACEHOLDER);
+			await expect(nameInput).toBeVisible({ timeout: 10_000 });
 
-		// Typing a prefix should narrow suggestions. "mi" matches "milk".
-		await nameInput.fill('mi');
-		await expect(page.getByRole('button', { name: /^milk$/i })).toBeVisible({ timeout: 3_000 });
+			// The strip renders the top of item_frequency. The seed has
+			// milk/bread/eggs/etc., and the list is empty so nothing is
+			// excluded — at least one chip must be there.
+			await nameInput.click();
+			await expect(page.getByTestId('item-suggestions-strip')).toBeVisible({ timeout: 5_000 });
+
+			// Typing a prefix narrows the chips; the strip still renders.
+			await nameInput.fill('mi');
+			await expect(page.getByRole('button', { name: /^milk$/i })).toBeVisible({ timeout: 5_000 });
+		} finally {
+			await page.evaluate(
+				async ({ id }) => {
+					const supabase = (
+						window as unknown as { __sb: import('@supabase/supabase-js').SupabaseClient }
+					).__sb;
+					await supabase.from('shopping_lists').delete().eq('id', id);
+				},
+				{ id: listId }
+			);
+		}
 	});
 });