To automatically obtain the processes for the island diffusion application example, we choose as initial atomic configuration a (4 × 4) square monolayer island plus one isolated adatom at a Pd(100) surface as already depicted in Fig. above. The surface is described as a four layer slab in a (10 × 10) periodic boundary condition supercell, and we al-low the adatom, all atoms of the island and all atoms of the first Pd(100) layer to freely move during the TS searches. The PES is determined with an embedded atom potential and we perform 100 TS searches for each entry in the to-do list, i.e. for each equivalence group denoting one distinct local atomic environment. DECAF with two-dimensional embedding and a cluster bandwidth of 0.048 , identifies ten equivalence groups in the initial atomic configuration. Detailed settings for the dimer search and prefactor calculations are provided in the SI. In the APE exploration phase, this is extended to 120 distinct equivalence groups that spread over a total of 46 different total atomic configurations that were generated as final state structures of identified processes. From 120 × 100 = 12000 TS searches launched, the outcome of the exploration phase are thus 7247 TSs with barriers within 20 k B T from the lowest barrier found (corresponding to a maximum absolute barrier of 1.36 eV). For further illustration, a part of the APE workflow is explicitly shown step by step in the SI. For the curation of this process list in the ensuing extraction phase we use a simple threshold of 0.55 Å to identify the significantly displaced atoms in each process. Again employing DECAF with the same settings, this extracts 777 unique processes as the central result of the APE framework. For comparison, we also ran the akMC code EON in different settings starting from the same initial state structure. After having spent the same computational budget in form of 12000 TS searches, EON had only identified less than a third of the unique process classes found by APE, with full details and a critical discussion on the use of akMC provided in the SI. As to be expected, the list of these APE identified unique processes contains the classic on-surface and exchange diffusion mechanisms . For an isolated adatom on Pd(100), on-surface diffusion proceeds via a TS at the bridge site to end up in a nearest-neighbor (NN) hollow site. In contrast, in exchange diffusion, the adatom pushes one of its directly coordinating Pd atoms of the topmost surface layer out into a second NN hollow site and takes its place instead. Including analogs of these two mechanisms at the perimeter of the island as e.g. illustrated in Fig. , this constitutes a group of 149 unique processes. With all likelihood, this group of processes would have been what a human researcher would have enumerated manually in the look-up table kMC strategy based on our current view of Pd island surface diffusion.