Worked on the vercel/vercel repository to deliver two features focused on improving CLI workflows and security. Developed environment-aware URL formation for resource provisioning, ensuring the --environment flag is consistently propagated through CLI and web UI flows, which reduced manual corrections and provisioning errors. Later, implemented an environment file safeguard for the vercel env pull command, updating default behavior to ignore .env* files in git and aligning with Next.js standards to prevent accidental exposure of sensitive data. Both features were built using TypeScript and involved CLI development, Git integration, and comprehensive unit testing to ensure reliability and alignment with existing patterns.