hideEmptyState();
        hideErrorBanner();
        updateUI();
        showStatus('thinking');
        showProgressIndicator();

        // Add user message
        addMessage('user', message);

        // Clear input
        elements.chatInput.val('');
        updateCharCount();
        autoResizeTextarea();

        // Add thinking indicator

     *
     * @param sessionId the session ID
     * @param message the message to add
     * @return true if the message was added, false if the session was not found
     */
    public boolean addMessage(final String sessionId, final ChatMessage message) {
        final ChatSession session = getSession(sessionId);
        if (session == null) {
            if (logger.isDebugEnabled()) {

        final ChatSession session = new ChatSession();
        final LocalDateTime beforeAdd = session.getLastAccessedAt();

        final ChatMessage message = ChatMessage.userMessage("Hello");
        session.addMessage(message);

        assertEquals(1, session.getMessages().size());
        assertEquals("Hello", session.getMessages().get(0).getContent());

        final Map<String, Object> doc = new HashMap<>();
        doc.put("title", "Doc Title");
        doc.put("url", "http://example.com");
        assistantMsg.addSource(new ChatSource(1, doc));
        session.addMessage(assistantMsg);

        final List<LlmMessage> history = chatClient.testExtractHistory(session);
        assertEquals(2, history.size());
        assertEquals("user", history.get(0).getRole());