diff --git a/content/en/history/bibliography/_index.md b/content/en/history/bibliography/_index.md
index 4a499831..b9c2823f 100644
--- a/content/en/history/bibliography/_index.md
+++ b/content/en/history/bibliography/_index.md
@@ -2,6 +2,7 @@
 title: Bibliography
 heading: Interlisp Bibliography
 type: bibliography
+robots: "noindex, follow"
 cascade:
     type: bibliography
     toc_hide: true
diff --git a/layouts/_partials/hooks/head-end.html b/layouts/_partials/hooks/head-end.html
index f800ce9f..14f526e3 100644
--- a/layouts/_partials/hooks/head-end.html
+++ b/layouts/_partials/hooks/head-end.html
@@ -1,3 +1,11 @@
 <link rel="canonical" href="{{ .Permalink }}">
 <link rel="me" href="https://fosstodon.org/@interlisp">
+{{- /* Emit a page-level robots directive when front matter sets `robots`.
+       Docsy's head.html already emits "index, follow" for production pages;
+       when both tags are present, search engines apply the most restrictive
+       rule, so a `noindex` value here wins. See the bibliography section's
+       _index.md. */ -}}
+{{ with .Params.robots }}
+<meta name="robots" content="{{ . | htmlEscape }}">
+{{ end }}
 {{ partial "bibliography-json-ld.html" . }}
diff --git a/layouts/bibliography/list.html b/layouts/bibliography/list.html
index 68cd602d..47b6334b 100644
--- a/layouts/bibliography/list.html
+++ b/layouts/bibliography/list.html
@@ -107,9 +107,9 @@ <h1 class="h3 m-0">{{ or .Params.heading .Title }}</h1>
           {{- $previewing := gt (countwords $plain) $previewWordLimit -}}
           {{- if $previewing }}
             {{- $previewWords := split $plain " " | first $previewWordLimit -}}
-            <div class="mt-2 small">{{ delimit $previewWords " " | safeHTML }}…</div>
+            <div class="mt-2 small" data-nosnippet>{{ delimit $previewWords " " | safeHTML }}…</div>
           {{- else }}
-            <div class="mt-2 small">{{ replace (. | htmlEscape) "\n" "<br>" | safeHTML }}</div>
+            <div class="mt-2 small" data-nosnippet>{{ replace (. | htmlEscape) "\n" "<br>" | safeHTML }}</div>
           {{- end }}
         {{ end }}
       </li>
diff --git a/layouts/sitemap.xml b/layouts/sitemap.xml
index 226bee19..ab0b33f6 100644
--- a/layouts/sitemap.xml
+++ b/layouts/sitemap.xml
@@ -2,6 +2,7 @@
 <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
   xmlns:xhtml="http://www.w3.org/1999/xhtml">
   {{ range (where .Data.Pages "Type" "!=" "redirect") }}
+  {{- if not (strings.Contains (.Params.robots | default "") "noindex") }}
   <url>
     <loc>{{ .Permalink }}</loc>{{ if not .Lastmod.IsZero }}
     <lastmod>{{ safeHTML ( .Lastmod.Format "2006-01-02T15:04:05-07:00" ) }}</lastmod>{{ end }}{{ with .Sitemap.ChangeFreq }}
@@ -18,5 +19,6 @@
                 href="{{ .Permalink }}"
                 />{{ end }}
   </url>
+  {{- end }}
   {{ end }}
 </urlset>