Technically speaking it's not just a bayonet
It's also a servicing/maintenance tool for the AK-47
P.S. though, judging by the bright straps, this one looks like it came from the Yugoslavian version of the AK47, the Zastava M70
You're right about tools:
I bought it for 5DM in W-Germany, some months after collapsing the DDR.
A LOT of material got here for sale on flee markets, the people needed DM !