This template is a notice for templates that may be used in citation templates. By default, it indicates the template is safe for use as shown above.

To indicate a template that should not be used in a citation template:

{{COinS safe|n}}

Citation templates such as Citation Style 1 and Citation Style 2 generate COinS metadata. If a template is used in a citation template field, then it may inject HTML into the metadata.

Compare the rendered HTML for {{cite book}} with |author= using no template and using {{smallcaps}}.

Markup Renders as
{{cite book |author=Sam Drucker |title=Title}}
Sam Drucker, Title 

<span class="citation book">Sam Drucker, ''Title''।</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fne.wikipedia.org%3A%E0%A4%A2%E0%A4%BE%E0%A4%81%E0%A4%9A%E0%A4%BE%3ACOinS+safe%2F%E0%A4%95%E0%A4%BE%E0%A4%97%E0%A4%9C%E0%A4%BE%E0%A4%A4&rft.au=Sam+Drucker&rft.aulast=Sam+Drucker&rft.btitle=Title&rft.genre=book&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;">&nbsp;</span></span>

{{cite book |author={{smallcaps|Sam Drucker}} |title=Title}}
Sam Drucker, Title 

<span class="citation book">'"`UNIQ--templatestyles-0000000A-QINU`"'<span class="smallcaps">Sam Drucker</span>, ''Title''।</span><span title="ctx_ver=Z39.88-2004&rfr_id=info%3Asid%2Fne.wikipedia.org%3A%E0%A4%A2%E0%A4%BE%E0%A4%81%E0%A4%9A%E0%A4%BE%3ACOinS+safe%2F%E0%A4%95%E0%A4%BE%E0%A4%97%E0%A4%9C%E0%A4%BE%E0%A4%A4&rft.au=%7F%27%22%60UNIQ--templatestyles-0000000A-QINU%60%22%27%7F%3Cspan+class%3D%22smallcaps%22%3ESam+Drucker%3C%2Fspan%3E&rft.aulast=%7F%27%22%60UNIQ--templatestyles-0000000A-QINU%60%22%27%7F%3Cspan+class%3D%22smallcaps%22%3ESam+Drucker%3C%2Fspan%3E&rft.btitle=Title&rft.genre=book&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook" class="Z3988"><span style="display:none;">&nbsp;</span></span>

The author metadata is in the rft.aulast field. In this case, it is percent-encoded and is rendered as <span class="smallcaps" style="font-variant:small-caps;">Sam Drucker</span>

Reference management software will interpret the entire span as the author name.