The wall-framing takeoff page already counts studs, rafters, siding, soffit and fascia. Tick the new gutter box under the roof options and it also counts gutter sections, downspout pieces, hangers, end caps, elbows, straps and (on a hip roof) outside corners, all from the roof's eave runs, and adds them to the budget when you type prices.
On the example house that is 84 ft of gutter in two runs, 10 sections with 10% waste, four downspouts and 44 hangers. The downspout count is a rule of thumb (one per 40 ft of run and one per 600 sq ft of roof), not a drainage design, and the numbers are hand-checked on one roof, not against a real gutter order. Bad inputs, such as a 5 ft longest run, are refused with the allowed range.
The engine and the command-line flag (--gutters) landed earlier the same day; this change wires them into the page and its saved plans. It is a small step in the new-home construction program in ventures/wall-framing-takeoff/ROADMAP.md.