Marking up images and pages
Short answer: Markup lets you give the AI feedback you’d otherwise have to describe in words: draw on an image, or drop comments onto a generated web page or SVG, then attach it. The AI revises against exactly what you marked instead of guessing where you meant.
What is markup?
Markup is for located feedback: pointing at the spot instead of describing it. Rather than typing “the header on the top right is too big,” you mark the header and say “too big.” Build Perch has three markup paths, depending on what you’re pointing at.
Draw on an image
Click the pencil button in the message bar to open a blank sketchpad, or right-click any image in a chat or gallery and choose Markup & Attach to draw on that image. You get a pen, shapes, text, an eraser, a color palette, and undo. When you finish, the marked-up image saves into your workspace and attaches to your next message. Because the AI reads your markup as an image, this needs a vision-capable model.
Comment on a generated page or SVG
When the AI builds an HTML page or an SVG, right-click the file in the Files panel and open its preview. Click elements to attach text comments right where they belong, then choose Attach Markup to Chat. Your positioned notes go back to the AI with the file, so it can revise against them without you spelling out each location.
Have the AI annotate an image
You can also ask the AI to mark up an image for you: label the parts of a diagram, box the error in a screenshot, point an arrow at something. It draws the annotations over a copy and leaves your original untouched.