Electroweak response functions are the quantities that connect cross-sections measured in lepton-scattering experiments to the structure and dynamics of the target nucleus. They encode how a nucleus absorbs energy and momentum from an external probe, and they are therefore the meeting point between nuclear many-body theory and a broad experimental program. In electron scattering inclusive response functions have been measured over a wide range of momentum transfers and provide some of the most stringent tests available of our understanding of nuclear currents and correlations. The same nuclear input governs the weak sector, where the experimental situation is far more demanding and the theoretical uncertainties matter far more. The principal motivation for this project comes from accelerator-based neutrino oscillation experiments, in particular DUNE and Hyper-Kamiokande. These experiments aim to determine the neutrino mass ordering and to search for leptonic CP violation, and their sensitivity depends on reconstructing the incident neutrino energy. That reconstruction is performed through a nuclear model: the neutrino energy is inferred from the kinematics of the outgoing lepton and hadrons using theoretical cross sections on the detector material, oxygen for Hyper-Kamiokande and argon for DUNE. Uncertainties in the nuclear response therefore propagate directly into the extracted oscillation parameters, and they are now recognised as one of the leading systematic limitations of the programme. Reducing them requires calculations that are not only accurate but that carry quantified, traceable theoretical uncertainties. This project computes inclusive electroweak responses in the region of the quasi-elastic peak. This kinematic region dominates the event rate at the flux energies of both experiments and is the region in which energy reconstruction is carried out, so its description directly controls the accuracy of the oscillation analysis. We use the ab initio nuclear approach: coupled-cluster method with interactions from chiral effective field theory, which provides a systematically improvable description of nuclei from first principles. Responses are obtained through the Lorentz Integral Transform, evaluated with the Lanczos algorithm and with Chebyshev moment expansions, and subsequently inverted to recover the response as a function of energy transfer. Calculations are performed for a grid of momentum transfers spanning the quasi-elastic region and repeated with interactions at successive chiral orders, which allows the truncation uncertainty of the underlying theory to be propagated into the final responses rather than estimated after the fact. The present allocation covers 4He, the lightest system for which the full machinery is required and one for which precise electron scattering data and independent theoretical benchmarks exist. Responses are computed for both the electromagnetic and the weak probe, so that the same currents and the same many-body treatment can be validated against electron scattering data and then carried over to neutrino kinematics without further assumption. It establishes the accuracy of the approach and the performance of the code on this system, and forms the basis for the subsequent extension to 16O and to heavier nuclei of direct relevance to the neutrino detectors.