Building a slide deck by hand in 2026 is like typing a spreadsheet by hand—it made sense once, but it doesn’t anymore. In this walkthrough, I show exactly how I use Claude Desktop’s Cowork tab to take a document I already have (in our case, a 14-page investment memo) and turn it into a fully designed PowerPoint deck automatically. The key is that Cowork is desktop-only right now because it needs access to a folder on your computer, so I set up a dedicated “cowork PowerPoint” folder and run everything from there. We go step-by-step through the prompt: define the audience, point Claude to the source doc, set constraints like slide count, and tell it to follow the formatting rules in a claude.md file. That claude.md is the real unlock—because instead of letting the model “guess” your style, you lock in your colors, fonts, slide layouts, and structure so every deck comes out consistent. I also show how Claude asks clarifying questions before generating (which improves accuracy), how to keep your computer awake during generation, and how to make edits or even add a brand-new slide with a vague prompt after the deck is built.