Fitting a tube kit, Allen wrench, tyre 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 inches by 7 inches 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 $US36.