Subsequently, the agent learned to satisfy the desired MPO objective via RL. Specifically, in the fragment linking experiment , we showed that Link-INVENT can propose plausible linker ideas that satisfy a molecular docking constraint with additional constraint over the permitted linker spatial occupancy by controlling for branching. More than 5000 unique Bemis-Murcko scaffolds were generated by the Link-INVENT agent, demonstrating that diverse linker ideas were explored. In the scaffold hopping experiment , we showed that Link-INVENT can simultaneously optimize a relatively complex MPO objective encompassing a molecular docking constraint and favourable central nervous system (CNS) compatible physico-chemical properties. In this experiment, Link-INVENT navigated a narrow solution space and proposed plausible scaffold ideas which satisfy all desired properties and are diverse as shown by the number of unique Bemis-Murcko scaffolds. In the PROTACs experiment , we further showed Link-INVENT's extensive user control on the linker properties. We demonstrated the ability to enforce the Link-INVENT agent to explore effective linker lengths within a specified interval while keeping physico-chemical properties within a specified range. Moreover, linker linearity can be controlled, enforcing the agent to explore only linear linkers or linkers containing rings. Finally, we prove that linker flexibility can be controlled via the "linker ratio of rotatable bonds" component which provides users with the ability to modulate the conformational entropy of proposed linker ideas. These series of PROTACs Sub-Experiments mimic real-world PROTACs linker design which typically investigate linkers of variable length and flexibility. Link-INVENT is a ready-to-use generative model for linker design with the capability to optimize bespoke MPO objectives via the flexible Scoring Function. The case studies in this work show how Link-INVENT can be applied to real-world drug discovery projects and that the agent proposes plausible and diverse linker ideas. The code is freely available at .