I have a little nylon stuff sack, smaller than a fist. It contains a pretty complete tool kit and I leave it in my saddlebag. It contains:
- Allen wrenches, short ones, in all the sizes needed for my bike (four, I think)
- Metal tire levers that are also hex wrenches, that fit the few hex fasteners on my bike.
- A very small chain tool.
- A spoke wrench.
- Patches, little tube of vulcanizing compound, small square of sandpaper.
- Spare derailleur and brake cables.
- Rolled up spare tube (used and tested).