diff --git a/_includes/layouts/post.njk b/_includes/layouts/post.njk
index 35e8c8b..a23bb0e 100644
--- a/_includes/layouts/post.njk
+++ b/_includes/layouts/post.njk
@@ -57,6 +57,42 @@ withBlogSidebar: true
     {{ content | safe }}
   </div>
 
+  {# AI usage disclosure #}
+  {% set aiTextLevel = aiTextLevel or ai_text_level %}
+  {% set aiCodeLevel = aiCodeLevel or ai_code_level %}
+  {% set aiTools = aiTools or ai_tools %}
+  {% set aiDescription = aiDescription or ai_description %}
+  {% if aiTextLevel or aiCodeLevel or aiTools %}
+  <aside class="mt-6 p-4 rounded-lg bg-surface-50 dark:bg-surface-800/50 border border-surface-200 dark:border-surface-700">
+    <div class="flex items-center gap-2 mb-2">
+      <svg class="w-4 h-4 text-surface-500 dark:text-surface-400 flex-shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24" aria-hidden="true">
+        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9.75 3.104v5.714a2.25 2.25 0 01-.659 1.591L5 14.5M9.75 3.104c-.251.023-.501.05-.75.082m.75-.082a24.301 24.301 0 014.5 0m0 0v5.714a2.25 2.25 0 00.659 1.591L19 14.5M14.25 3.104c.251.023.501.05.75.082M19 14.5l-2.47 2.47a2.25 2.25 0 01-1.59.659H9.06a2.25 2.25 0 01-1.591-.659L5 14.5m14 0V17a2 2 0 01-2 2H7a2 2 0 01-2-2v-2.5"/>
+      </svg>
+      <strong class="text-sm font-semibold text-surface-700 dark:text-surface-300">AI Usage</strong>
+    </div>
+    <div class="flex flex-wrap gap-3 text-xs text-surface-600 dark:text-surface-400">
+      {% if aiTextLevel %}
+      <span class="inline-flex items-center gap-1 px-2 py-0.5 rounded bg-surface-100 dark:bg-surface-700">
+        Text: {% if aiTextLevel === "0" %}None{% elif aiTextLevel === "1" %}Editorial{% elif aiTextLevel === "2" %}Co-drafted{% elif aiTextLevel === "3" %}AI-generated{% endif %}
+      </span>
+      {% endif %}
+      {% if aiCodeLevel %}
+      <span class="inline-flex items-center gap-1 px-2 py-0.5 rounded bg-surface-100 dark:bg-surface-700">
+        Code: {% if aiCodeLevel === "0" %}Human{% elif aiCodeLevel === "1" %}AI-assisted{% elif aiCodeLevel === "2" %}AI-generated{% endif %}
+      </span>
+      {% endif %}
+      {% if aiTools %}
+      <span class="inline-flex items-center gap-1 px-2 py-0.5 rounded bg-surface-100 dark:bg-surface-700">
+        Tools: {{ aiTools }}
+      </span>
+      {% endif %}
+    </div>
+    {% if aiDescription %}
+    <p class="mt-2 text-xs text-surface-500 dark:text-surface-400">{{ aiDescription }}</p>
+    {% endif %}
+  </aside>
+  {% endif %}
+
   {# Rich reply context with h-cite microformat #}
   {% include "components/reply-context.njk" %}
 
diff --git a/blog.njk b/blog.njk
index 2b9eb5f..996d1ad 100644
--- a/blog.njk
+++ b/blog.njk
@@ -328,6 +328,16 @@ permalink: "blog/{% if pagination.pageNumber > 0 %}page/{{ pagination.pageNumber
         </a>
       </div>
       {% endif %}
+
+      {# AI usage badge #}
+      {% set postAiText = post.data.aiTextLevel or post.data.ai_text_level %}
+      {% set postAiCode = post.data.aiCodeLevel or post.data.ai_code_level %}
+      {% if postAiText or postAiCode %}
+      <span class="inline-flex items-center gap-1 mt-2 px-1.5 py-0.5 rounded text-[10px] font-medium bg-surface-100 dark:bg-surface-700 text-surface-500 dark:text-surface-400" title="AI usage: Text level {{ postAiText or '–' }}, Code level {{ postAiCode or '–' }}">
+        <svg class="w-3 h-3" fill="none" stroke="currentColor" viewBox="0 0 24 24" aria-hidden="true"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9.75 3.104v5.714a2.25 2.25 0 01-.659 1.591L5 14.5M9.75 3.104c-.251.023-.501.05-.75.082m.75-.082a24.301 24.301 0 014.5 0m0 0v5.714a2.25 2.25 0 00.659 1.591L19 14.5M14.25 3.104c.251.023.501.05.75.082M19 14.5l-2.47 2.47a2.25 2.25 0 01-1.59.659H9.06a2.25 2.25 0 01-1.591-.659L5 14.5m14 0V17a2 2 0 01-2 2H7a2 2 0 01-2-2v-2.5"/></svg>
+        AI{% if postAiText %}: T{{ postAiText }}{% endif %}{% if postAiCode %}/C{{ postAiCode }}{% endif %}
+      </span>
+      {% endif %}
     </li>
     {% endfor %}
   </ul>