During January 2026, Tobias Birchler enhanced data flow control and encoding robustness across the pytorch/tensordict and pytorch/rl repositories. He developed selective output key functionality for the ProbabilisticTensorDictSequential class, allowing users to specify which keys to include in outputs and improving downstream data processing. In pytorch/rl, Tobias addressed batch size handling in Composite encoding, ensuring correct TensorDict creation and adding targeted tests to validate output shapes. His work leveraged Python, data structures, and testing methodologies to improve reliability and usability. The contributions demonstrated thoughtful engineering depth, focusing on robust, maintainable solutions for machine learning data workflows and model development.