client.testAddHistoryWithBudget(request, history, 10);
        // Q2 and A2 fit (4 chars), Q1 fits (6 chars), but A1 is too large and skipped
        // Pair integrity: Q1 without A1 => Q1 excluded
        // Result: Q2, A2
        assertEquals(2, request.getMessages().size());
        assertEquals("Q2", request.getMessages().get(0).getContent());

        session.addUserMessage("Q1");
        session.addAssistantMessage("A1");
        session.addUserMessage("Q2");
        session.addAssistantMessage("A2");

        final List<LlmMessage> history = chatClient.testExtractHistory(session);
        assertEquals(4, history.size());
        assertEquals("user", history.get(0).getRole());
        assertEquals("Q1", history.get(0).getContent());