Well, we heard of one possible mechanism of monetary policy in the blog, which is to change the mining reward, but as the blog mentions, using such a thing as a monetary instrument is quite risky. I want to suggest another possible monetary instrument: Use proof-of-stake returns as the monetary mechanism.
So you probably know Slasher. In Slasher PoS, if you are picked randomly, you can sign blocks, but your reward is held back for a moment while others make sure you haven't signed a block multiple times; if you didn't cheat, you get the reward after a bit of waiting.For the purposes of this idea, I'll make a slight adjustment: Instead of having to pray to be chosen by RNG, you can participate in staking by buying rights to stake and doing the whole PoS dance. When your block is fully checked, you get your money back plus a small reward.
Now we have something resembling a bond. You put money in it, and after a while, you get your money back plus a bit more. And we can change the money supply by changing the return on these "slasher bonds", which I will refer to them as. If we increase the return of the slasher bonds, more people will sink their money into slasher bonds and less currency will end up circulating around; if we decrease the return, fewer people will want slasher bonds, and the money that might have been in the bonds will be available for other purposes. So we have a simple tool to influence monetary supply with fewer risks and faster effects than if we merely controlled PoW returns.