#  `tag`

Auto-tag a PDF for accessibility using OpenDataLoader
## Usage
> pdftl `<input>` `tag` `[<option>...]` `output` `<file>`

## Details
Auto-tag a PDF file for accessibility (PDF/UA readiness) using OpenDataLoader.

This operation runs the OpenDataLoader auto-tagging pipeline to perform layout analysis,
structure discovery, and inject standard accessibility tags following the Well-Tagged PDF
specification.

### Options

Options are specified as `key=value` arguments:

* `table_method=<default|cluster>`
  Table detection method. `default` is border-based,
`cluster` uses borders and clustering.
* `reading_order=<off|xycut>`
  Reading order algorithm. Default is `xycut`.
* `pages=<spec>`
  Specific pages to tag (e.g., `1,3,5-7`). Default is all pages.
* `threads=<int>`
  Number of worker threads for parallel per-page processing (native Java
pipeline only).
* `hybrid=<off|docling-fast|hancom-ai>`
  Enable a hybrid backend server for advanced layout
analysis.
* `hybrid_mode=<auto|full>`
  Hybrid triage mode. Default is `auto`.
* `hybrid_url=<url>`
  Custom hybrid backend server URL.

Note: This operation requires Java 11+ to be installed on your system and available on your PATH,
as well as the `opendataloader-pdf` Python package. THe `hybrid` options require further
infrastructure to be set up; see the OpenDataLoader documentation for details.

### See also

The [`set`](<set.md>) operation may be used to set the document language and title, for enhanced accessibility.
## Examples

> Auto-tag the entire PDF with default settings.
```
pdftl in.pdf tag output out.pdf
```

> Auto-tag using the cluster table method and the docling-fast hybrid backend.
```
pdftl in.pdf tag table_method=cluster hybrid=docling-fast output out.pdf
```

> Auto-tag only the first 5 pages using 4 parallel threads.
```
pdftl in.pdf tag 1-5 threads=4 output out.pdf
```


**Tags**: accessibility, tagging, tagged-pdf, pdf-ua, tags

*Source: pdftl.operations.tag*

*Read online: [https://pdftl.readthedocs.io/en/latest/operations/tag.html](https://pdftl.readthedocs.io/en/latest/operations/tag.html)*

*Type: Operation*