According to the AP,
The United States launched multiple airstrikes against Islamic State militants in Libya on Monday, opening a new, more persistent front against the group at the request of the United Nations-backed government, Libyan and U.S. officials said... Serraj said his government is joining the coalition against IS, adding, "This is the time for the international community to live up to its promises to the Libyan people."...
Pentagon press secretary Peter Cook said President Barack Obama authorized the strikes following a recommendation from Defense Secretary Ash Carter and Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff. Cook told reporters that U.S. Africa Command will coordinate any strikes with the Libyans and that the new air campaign will last as long as the Libyans request assistance to eliminate IS from Sirte. The U.S. is also providing airborne surveillance and intelligence.Mohammed al-Ghasri, the commander of a pro-government militia known as al-Bonyan al-Marsous, said his forces gave target coordinates of Islamic State positions to the U.S. You can read the whole article here.
According to Jason Pack, "I think the short term impact is outrage on the libyan street that their government is in such open cahoots with the West. The medium term impact is that a sustained campaign could help BM breakthrough against ISIS in Sirte. But the long term impact is only negative because the US has agreed to help with airstrikes without a genuine anti-ISIS coalition being formed and without that it is irrelevant. Even if Sirte were to be liberated, ISIS will still persist in Libya and the political impasse will not be solved. What is needed is sustained political engagement, not just airstrikes."