Fitting a tube kit, Allen wrench, tire tool, phone, and wallet into a pair of skinny jeans is nigh on impossible and carrying a backpack just to hold these small items is way inefficient. Instead, roll them up before you roll out.
The Mopha roll measures 16" by 7" when opened and is constructed of waxed canvass with 10 pockets of various sizes for all your riding necessities. When closed, the Mopha cinches under your seat with a leather toe strap or can be stored in the water bottle cage. It's available from Etsy and retails for $36.