One of the challenges in benchmarking bosonic qubit gates is the large Hilbert space that the states can occupy. To overcome this, we use coherent states as probes and observe how the process affects them, enabling us to fully characterize the quantum process. Our method involves reconstructing Kraus operators for a large Hilbert space, rather than being limited to the logical subspace, allowing for a more accurate determination of the process. This approach offers a more effective way to benchmark bosonic qubit gates, and enables precise measurements of the population leakage outside of the computational subspace. Find more here.