Keynes differs from neoclassical economists on the necessary government response to a recession because:

Keynes believed that governments should intervene in the economy only in the case of an outside shock $($like COVID$-19$ or some natural disasters$)$

Keynes believed that governments should increase spending to make up for a deficiency of aggregate demand.

Keynes believes that governments can prevent an outside shock by running budget surpluses and minimizing the national debt.

Keynes believed that governments do not need to intervene, because the economy is always in $($or tending to$)$ fullemployment equilibrium.