Did Eve add anything to God's command about the forbidden tree?
Yes. Eve added the words "neither shall you touch it" to God's command about the forbidden tree. She added this restriction beyond what God had said, while the warning remained that they should not eat of it, lest they die.
Les explains that when Eve was confronted by the serpent, she said the fruit of the tree in the midst of the garden was not to be eaten and not to be touched. Les notes that "neither shall you touch it" was something Eve added. The result, however, was still death: to disobey the revealed will of God is sin, and the sinner dies, both spiritually and physically. Ezekiel 18:4 repeats that the soul that sins will die, with no exceptions.
But of the fruit of the tree which is in the midst of the garden, God hath said, Ye shall not eat of it, neither shall ye touch it, lest ye die.