assertEquals("A2", request.getMessages().get(2).getContent());
        assertEquals("Q3", request.getMessages().get(3).getContent());
    }

    @Test
    public void test_addHistoryWithBudget_singleLargeMessage_truncation() {
        // Single message larger than budget triggers truncation fallback
        final List<LlmMessage> history = new ArrayList<>();
        history.add(LlmMessage.user("A".repeat(500)));