History. You can determine the age and origin of objects, even if you have only a few pieces remaining from the original.
Investigation. When you inspect a damaged object, you gain knowledge of how it was damaged and how long ago.
Repair. You can restore 10 hit points to a damaged object for each hour of work. For any object, you need access to the raw materials required to repair it. For metal objects, you need access to an open flame hot enough to make the metal pliable.
Additional uses. You can use your tinker's tools to do a variety of things, as your DM if you may use the tools for a specific task. Examples of such tasks are as follows; Temporarily repair a disabled device, repair an item in half the time of what it usually would take, improvise a temporary item using scraps.