Worked on the mbta/api repository to update developer documentation, focusing on aligning onboarding materials with the current Phoenix framework workflow. The primary contribution involved revising the README to replace the deprecated 'mix phoenix.server' command with the correct 'mix phx.server', ensuring that new developers can start the server without confusion. This change, implemented using Markdown and knowledge of Phoenix and Elixir, addressed a common source of onboarding friction and reduced the likelihood of support requests related to outdated instructions. The work demonstrated attention to detail in documentation and effective change management around framework deprecations, supporting a smoother developer experience.