Maybe/app/views/assistant_messages/_assistant_message.html.erb

<%# locals: (assistant_message:) %>

<div id="<%= dom_id(assistant_message) %>">
  <% if assistant_message.reasoning? %>
    <details class="group mb-1">
      <summary class="flex items-center gap-2">
        <p class="text-secondary text-sm">Assistant reasoning</p>
        <%= icon("chevron-down", class: "group-open:transform group-open:rotate-180") %>
      </summary>

      <div class="prose prose--ai-chat"><%= markdown(assistant_message.content) %></div>
    </details>
  <% else %>
    <% if assistant_message.chat.debug_mode? && assistant_message.tool_calls.any? %>
      <%= render "assistant_messages/tool_calls", message: assistant_message %>
    <% end %>

    <div class="flex items-start gap-3 mb-6">
      <%= render "chats/ai_avatar" %>

      <div class="prose prose--ai-chat"><%= markdown(assistant_message.content) %></div>
    </div>
  <% end %>
</div>