and activation barrier E act , also defined as normal distributions (Supplementary Note 8). Since the GNN is trained on single adsorbates on the surface, bimolecular surface reactions A * +B * → C * + * are energetically evaluated in the bond-breaking direction (C * + * →A * +B * ) to construct the TS from the reactant graph by labelling the corresponding broken bond. The products are then evaluated separately, assuming absence of lateral interactions. As fallback strategy, CARE automatically treats steps as barrierless if GAME-Net-UQ predicts TS energies between the initial and final states. For electrochemical processes, the computational hydrogen electrode (CHE) approach is used to include the effect of applied potential and electrolyte pH to the energies. Reactions involving species not bonded to the surface, such as adsorption/desorption and PCET steps involving -OH removal and the formation of water, can be evaluated with GAME-Net-UQ as it has been trained with closed-shell gas phase molecules.