Yeah, forget the chain tool...like Kerry, I easily have +300k over 35 years in the saddle and have only had ONE chain incident. That is what a cell phone is made for. And that was my fault, not a chain failure.
I do carry a multitool, you never know when you are going to knock your bars or saddle out after a crash, the 3/4/5mm hex is just plain necessary.
I will give a plug for the Park tire boots. Started using them last summer, and this Spring I got a chance to finally use not one but two of them on the road and they do work...very well...much better than other alternatives (and I have tried many).
ID, med card, old MV license or photocopy of same, Road ID, whatever you choose...a must.
•Inflator: I use CO2, so 2 or 3 threaded 16oz cartridges (depending on ride) with just the Proflate head...I prewrap the cartridges with cloth med tape, (you will appreciate that fact in the summer when a cartridge freezes to your hand, also can be used for wounds, see below

•spare tube(s) (pretalc them and keep them in a ziplock bag to protect them)
•two tire levers (in the heat of the summer or dead of winter) very sweaty hands or numb fingers are often incapable of starting the tire off the rim.
•multi-tool (I think it is a workforce one)
•patchkit (the Park mini one is perfect)
•tire boot(s) (as mentioned the Park one is good)
•presta to schrader adaptor (just in case you need a gas station pump)
•Money: I keep $100 rolled up in my bars for emergencies, also a Credit Card, and cash.
•Cell Phone, and knowledge of LBSs, icecream stands (bananas, water refills), along my routes.
•sterile gauze pad and small packet of bacitracin and two ibuprofens (med tape on cartridges comes in handy here, if needed)
•house key
•cell phone (one with mapping is great, GPS is a bonus)
•plastic ziplock bag. I keep my stuff in small zip bags, partly to keep them dry on wet days, but I always keep my cell phone in one in my back pocket.
I fit all this into a the small Trek saddle bag (except for the cell phone). On much longer rides, I have a mid size bag that I use with extra tubes and cartridges.
HTH
zac