What the document says about itself, said once
Write what the file says about itself in its metadata packet alone, with no table of entries beside it.
Summary
A PDF carries its label twice: a short table where reading software looks up the title or the author, and a fuller description written in a format any program can read. The two say the same thing, and a checker holds them to each other. A file may keep the fuller description alone, whatever version of the format it declares, so that each fact is stated once and there is nothing left to keep in step.
Technically
Written at the top level of a request, under
"information_dictionary"
information_dictionary with enabled set to false writes no /Info dictionary and no trailer entry naming one: what metadata states is written in the XMP /Metadata packet alone, which the file then carries whether or not it claims a standard. The trailer entry naming that dictionary is optional at every version of the format (ISO 32000-2, table 15), so a request drops the dictionary under whatever version it declares. The engine refuses an entry named through metadata.info, which no property of the packet stands for, and private_data with neither metadata.modified nor metadata.created, since the dictionary is what writes the moment the data carries. A document claiming pdfa4 or pdfa4f writes no dictionary whatever this key says.
Request schema
-
information_dictionary— object, optional, absent by default. -
information_dictionary.enabled— boolean, optional,trueby default. Set tofalse, the table of entries is not written and the metadata packet alone says what the document is. -
Refused beside it: an entry named through
metadata.info, andprivate_datawith neithermetadata.modifiednormetadata.created. Each refusal comes from the engine, which says which of them the file cannot hold. Noversionrefuses it: the entry is optional at every one of them.
A whole request that creates a PDF
{
"version": "2.0",
"information_dictionary": { "enabled": false },
"metadata": {
"title": "Order 4471",
"keywords": "order, despatch, 4471",
"modified": "2026-06-18T17:05:00+02:00"
},
"standard_fonts": [{ "name": "sans", "face": "helvetica" }],
"items": [
{
"type": "text",
"rect": { "llx": 60, "lly": 740, "urx": 535, "ury": 762 },
"content": ["Order 4471"],
"font": "sans",
"font_size": 14
}
]
}The document as a whole
The numbers reading software shows A hundred letters in a single file What the document says about itself The notes a program leaves in the file for itself The notes a program leaves on one page The data a program hangs on a run of ink A file still readable decades from now The print standard the document claims The password that opens it, and what may be done with it An invoice a person and a machine both read The address relative links are read against The PDF version the file declares What a picture says about itself, and how it is read The attachments the document carries beside its pages The attachments shown as a portfolio Which attachments a page claims The identity card a single page carries The accessibility standard the document claims The standards the finished document is measured against
Where to go next
Every JSON key of a request, in one page The other forty-one settings of a request