Mossaab Souaissa developed a legitimacy verification layer, PRISM 153-key, for model selection within the vllm-project/semantic-router repository. This feature introduced a structured approach to verifying model responses based on query context, enhancing governance and safety in the vLLM-SR framework. Mossaab designed the architecture and integration points in Go, updating design principles to clarify the new layer while maintaining existing behaviors. He also strengthened documentation by adding a detailed proposal file in Markdown and improved CI hygiene by integrating lint checks into the pull request workflow. The work demonstrated depth in backend development, system architecture, and API design within a complex system.