Matterhorn 28-012 · PDF/UA-1 UA1:7.18.5-2

Link annotation with no Contents description

Link annotations need /Contents describing where the link goes.

What a screen reader actually does

The links list shows entries with no description, and a bare URL is read character by character.

What is in the file

The description lives on the annotation:

19 0 obj
<< /Type /Annot
   /Subtype /Link
   /Rect [ 72 640 300 660 ]
   /F 4
   /Contents (Privacy notice, opens example.gov)     % ← this
   /A << /S /URI /URI (https://example.gov/privacy) >>
   /StructParent 3
>>
endobj

Condition 28-012 is /Contents being absent or empty on a link annotation that is otherwise in scope — not hidden, not outside the crop box.

It is a separate condition from 28-011, which is about the link having a <Link> structure element at all. A link can be perfectly placed in the structure tree and still have no description, and vice versa. Both are needed.

What the user gets

Screen readers give users a links list — Insert + F7 in NVDA, VO + U in VoiceOver — which is how most people navigate a document’s links. That list shows the link text, and where the text is unhelpful the reader falls back to whatever else it can find.

With no description and text reading “click here”, the list is a column of identical entries. With a bare URL as the text, the entry is read character by character:

h t t p s colon slash slash e x a m p l e dot g o v slash p r i v a c y

Thirty seconds to hear one link. On a page with twelve references, the links list becomes the slowest way to navigate the document rather than the fastest.

How to fix it free, in Acrobat Pro

Acrobat has no field labelled “link description”, which is why this gets missed. It is on the structure element:

1. Open the Tags panel.
2. Find the <Link> element containing the link. If there is no <Link> element, fix 28-011 first: select the tag containing the link text, then Options → Find → Unmarked Links → Find → Tag Element.
3. Right-click the <Link> → Properties.
4. Type into Alternate Text.

That writes an /Alt on the structure element, which PDF/UA-1 accepts in place of /Contents on the annotation. Both satisfy the condition; /Contents is what more readers look at first, and it is what Taggart writes.

Upstream: Word and InDesign both export real hyperlinks as tagged <Link> elements, and Word carries a ScreenTip (Insert → Link → ScreenTip) into the export as the description. Setting ScreenTips in the source is the only version of this job that scales.

Writing link text that survives the links list

The links list removes all context, so the text has to carry its own. Three rules that hold up:

Never “click here”, “read more”, “here” or a bare URL.

Front-load the distinguishing word. Privacy notice (PDF, 240 KB) beats Download our privacy notice as a PDF — the first two words already identify it.

Two links with the same text must go to the same place. Otherwise the list contains two identical entries with different destinations, and the user has no way to choose.

Where Taggart differs

Taggart reports each link with its page and object id, so you can find it:

A link annotation on page 3 has no /Contents entry describing where the link goes.

The description is a human decision and Taggart will not invent one. What it offers is a starting point: with useUriAsDescription set, it writes the target URI as the description and marks every one it filled that way in the change log —

page 3: set link /Contents to ‘https://example.gov/privacy’ (derived from the target URI — review the wording)

— so it never reads as a wording somebody chose. A bare URI announced is poor; a link announced with no destination at all is worse, and the log makes clear which you have.

How Taggart handles it

Taggart detects this condition automatically. It is reported as a blocker, with the page, the structure path and the object id of every occurrence.

The fix is Build link structure elements. It changes what the document means, so Taggart proposes it and waits for your approval rather than applying it unattended.

Where this sits in the standards

Related conditions

• 28-011 A link annotation is not nested within a Link tag A link annotation must be a child of a Link structure element containing the link's text, joined by an object reference (/OBJR).
• 13-002 A link with a meaningful background lacks alternative text for both An image link — a button, a logo that navigates — needs alternative text that conveys both what the graphic shows and where the link goes.
• 28-004 An annotation has neither a Contents entry nor an alternative description Every non-widget annotation needs an accessible description, either in its own /Contents or in the /Alt of the structure element that encloses it.
• 28-013 An IsMap entry is true but the functionality is not provided in some other way A server-side image map requires pointing at a pixel, which is not possible without a mouse.

Other conditions in checkpoint 28

Checkpoint 28 covers annotations. These are its other failure conditions; the ones without a link are in the rule set but do not have a written page yet.

• 28-001 An annotation is not in correct reading order The annotation's position in the structure tree does not match where it appears on the page.
• 28-002 An annotation is not a direct child of an Annot structure element Non-widget, non-link annotations must sit inside an Annot structure element so they have a place in the reading order.
• 28-003 An annotation is used for visual formatting but is not tagged according to its semantic function A Square or Line annotation used to draw a box round a callout is decoration and should be artifacted, or tagged for what it actually means.
• 28-004 An annotation has neither a Contents entry nor an alternative description Every non-widget annotation needs an accessible description, either in its own /Contents or in the /Alt of the structure element that encloses it.
• 28-005 A form field has neither a TU entry nor an alternative description The /TU tooltip is the accessible name of a PDF form field. Without it the field has no name at all — the visible label printed next to it is not connected to the control.
• 28-006 An annotation with subtype undefined in ISO 32000 does not meet 7.18.1 A custom annotation subtype still has to be placed in the structure tree and described.
• 28-007 An annotation of subtype TrapNet exists TrapNet annotations are prepress artefacts and are forbidden in PDF/UA-1.
• 28-008 A page containing an annotation does not contain a Tabs entry Any page carrying annotations must declare a tab order. PDF/UA-1 requires /Tabs /S — tab order follows the structure tree.
• 28-009 A page containing an annotation has a Tabs entry with a value other than S /Tabs is present but set to /R (row order) or /C (column order) rather than /S (structure order).
• 28-010 A widget annotation is not nested within a Form tag Every form control must sit inside a Form structure element.
• 28-011 A link annotation is not nested within a Link tag A link annotation must be a child of a Link structure element containing the link's text, joined by an object reference (/OBJR).
• 28-013 An IsMap entry is true but the functionality is not provided in some other way A server-side image map requires pointing at a pixel, which is not possible without a mouse.
• 28-014 CT entry is missing from the media clip data dictionary The media clip's content type (/CT) is required so a processor knows what it is being asked to play.
• 28-015 Alt entry is missing from the media clip data dictionary Media clips require an /Alt array giving a text description.
• 28-016 File attachment annotations do not conform to 7.11 The file specification referenced by a FileAttachment annotation must carry both /F and /UF.
• 28-017 A PrinterMark annotation is included in the logical structure Crop marks and registration targets are production artefacts and must not appear in the structure tree.
• 28-018 The appearance stream of a PrinterMark annotation is not marked as Artifact The content inside a PrinterMark's appearance stream must itself be artifacted.

Verified against a real document on 2026-09-09 . Last updated 2026-09-10 .