diff --git a/plugins/astro-agent-docs.mjs b/plugins/astro-agent-docs.mjs
index 90f9686..637ed4d 100644
--- a/plugins/astro-agent-docs.mjs
+++ b/plugins/astro-agent-docs.mjs
@@ -87,6 +87,9 @@ const SECTIONS = deriveSections(sidebar);
 // a charset=utf-8 in the Content-Type header.
 const BOM = "\uFEFF";
 
+const LLMS_TXT_DIRECTIVE =
+  "> For the complete documentation index, see [llms.txt](/llms.txt)\n\n";
+
 /** Strip YAML frontmatter, HTML comments, and MDX artifacts; prepend title heading. */
 function cleanMarkdown(raw, isMdx = false) {
   const { data, content } = matter(raw);
@@ -96,7 +99,7 @@ function cleanMarkdown(raw, isMdx = false) {
   }
   body = body.replace(/\n{3,}/g, "\n\n").trim();
   const title = data.title ? `# ${data.title}\n\n` : "";
-  return BOM + title + body + "\n";
+  return BOM + title + LLMS_TXT_DIRECTIVE + body + "\n";
 }
 
 /**
diff --git a/public/_headers b/public/_headers
new file mode 100644
index 0000000..73888bd
--- /dev/null
+++ b/public/_headers
@@ -0,0 +1,2 @@
+/*.md
+  Content-Type: text/markdown; charset=utf-8