What Claude does with a Markdown file, and where a PowerPoint deck fits

Claude takes Markdown through a message attachment, or the knowledge base of a Project, and that is the door this page is about. The question worth asking is what a PowerPoint deck looks like by the time it arrives, because Claude never sees the deck itself. It sees whatever the conversion handed over, and nothing else.

Claude reads a fenced code block as something not to paraphrase and a heading as a citable section. What comes out of a PowerPoint deck here is one section a slide, with the presenter notes underneath and the chart data written out as a table, so the structure Claude is looking for is actually present instead of merely implied. That is the entire trick, and there is nothing clever underneath it.

What survives from a PowerPoint deck into Claude

The conversion drops master slides, transitions, animation order and the placeholder boxes nobody filled before Claude ever sees them, because none of it carries meaning into Claude and all of it costs something. What it keeps is the part you would otherwise have retyped by hand.

• Slide text comes through as one section a slide, so the running order is readable, and Claude receives it as structure rather than as something to infer.
• Presenter notes are extracted, and they are usually where the argument actually lives, which is the part Claude would otherwise have to reconstruct on its own.
• Chart categories and series are extracted as data instead of being left to a model to guess, so nothing downstream of Claude has to guess at it.

What Claude never gets back from a PowerPoint deck

Every conversion costs something, and a page listing only the gains is a sales page. Here is what a PowerPoint deck gives up on the way to Claude, stated plainly enough that you can decide against it.

• Layout, animation and build order are gone, and a build order sometimes was the argument, and Claude will not get it back from anywhere.
• Images are left out entirely when the option is off, and returned as encoded text when it is on, so nothing you build in Claude should depend on it.
• The speaker is gone, and with the speaker everything said over the slide, which is a real cost inside Claude and not a rounding error.

The PowerPoint to Markdown step behind this Claude page was measured

python-pptx on a machine we rent and watch does the conversion, and it was proven end to end on 13 August 2026: a deck carrying an image, presenter notes and a chart came back with the notes extracted and the chart categories and series read as data rather than guessed at. That is one run on one day and not an average, which is exactly why the date travels with the claim instead of being left out of it. The same output is what Claude would have received.

A deck whose meaning lived in its diagram arrives as a list of labels, and a list of labels is not a diagram. Claude has no way of telling you any of that from the inside, so it gets said here instead, on the page that sent you there.

Once the deck is Markdown, what to do inside Claude

With the Markdown in hand, load the Markdown into a Project once, so every later conversation starts from it instead of re-uploading. That is a Claude habit rather than a conversion setting, and it is where most of the value of converting a PowerPoint deck in the first place actually lands.

The constraint worth knowing before you start: a window of 200k tokens is large enough to hide the exact moment a document stopped fitting inside it. It bites the same way whether the Markdown came out of a PowerPoint deck or out of something else entirely, but it bites hardest on long documents, which is what a PowerPoint deck usually is.

What we will not pretend about PowerPoint in Claude

• Claude will not re-read an attachment you replaced unless you say so, and converting a PowerPoint deck first does not change that in the slightest.
• long context rewards structure and punishes filler, so extracted layout costs accuracy twice over, which is a Claude behaviour rather than anything the deck conversion did.
• The conversion costs half a credit and the price is shown before the deck is sent, whether the Markdown ends up in Claude or nowhere at all.