## Assistants
### New Features
* Introducing support for the `input_file` message type in Next-Gen
Assistants.
* For PDF documents, on models with vision capabilities, such as gpt-4o
and later models, the API extracts both text and page images and sends
both to the model.
* For non-PDF document and text files (for example, `.docx`, `.pptx`,
`.txt`, and code files), the API extracts text only.
* For spreadsheet files (for example, `.xlsx`, `.csv`, `.tsv`), the API
parses up to the first 1,000 rows per sheet and adds model-generated
summary and header metadata so the model can work from a smaller,
structured view of the data.

### Notes
* The `input_file` message type is currently unavailable for
user-uploaded files in Next-Gen Assistants. The model will continue
utilizing File Search and Code Interpreter for PDFs and other documents.

## Lecture Slides (Preview)

> [!NOTE]
> This release adds new capabilities for Lecture Slides, which remain
under active development and are not yet officially supported in Groups.
APIs, features, and UI/UX may change before final release.
>
> Lecture Slides mode is currently visible only to institutional admins
when creating an assistant.

### Updates & Improvements
* Lecture Slides chat now uses slide narrations, knowledge checks,
playback state, and the original slide PDF as context instead of
separately generated summary checkpoints and moment contexts.
* The slide processing pipeline now generates only knowledge checks for
lecture slide manifests, reducing generation work and keeping chat
context closer to the source slides.
* Existing lecture slide PDFs can be backfilled into OpenAI file storage
so previously created slide decks can use the same PDF-grounded chat
context.