car didnt start, battery is fine

[jts98z28]

okay, so i drove to work this morning with no issues, and 5 hours later when i go to take lunch break the car didnt start.
it was normal when i first put the key in, all the gauges were working and everything, then as soon as i went to start it everything just stopped. ive looked around and a lot of people have had a similar issue but radio and stuff still works, but my car was acting like it had a dead battery, no radio, no windows, gauges not even trying to move, no interior lights, and there was a very rapid clicking noise from what i assume is the BCM, about 1-2 times per second. when i took the key out and closed the door it stopped clicking, but if i had the door open and the key in the on position it stopped as well.
i assumed it was a bad battery but when i tested it, it had 12.7 volts. so i got my brother to give me a jump and it started right up, no problems and ran fine. i was even able to turn it off and turn it on a few minutes later without issue. but my main concern is this happening again, since i have no idea what it is does anyone have any suggestions?
thanks

[NJ Torque]

Okay... what kind of car?

[V]

check and clean terminals. most likely attaching the jumper cables made them create a connection again.

[jts98z28]

its an 01 z28, i am thinking of replacing the terminals and the positive cables, the car has a normal top terminal battery instead of the side terminals and it has the real cheap kind you get for like $3 on there now, and i have like 30ft of battery cable laying around so ill prolly just throw that in there too
i didnt see any blown fuses or obvious electrical issues and the car has been starting no problem since it happened so i guess it makes sense that it could just be the terminals and/or the battery cable
thanks for the input

[sweetbmxrider]

Sounds like a poor connection.

[foxriderry]

no ones thinking a lack of cold cranking amps as a possibility as well? correct me if im wrong but I thought it was amps that start the car not necessarily voltage. i agree always check connections, but just because the battery has 12.7 volts does not necessarily signify that it is good, if you have AAA you could call and have them do a full test of the battery and alternator for free, may be a worthwhile investment of time after you replace your connections and so on good luck with the diagnosis