Worked on the zed-industries/zed repository to resolve a critical issue affecting AWS Bedrock model routing in non-US regions. Addressed failures with Claude Sonnet 5 and Claude Fable 5 by implementing logic in Rust to default to a global inference profile when regional profiles are unavailable, ensuring reliable model invocation outside the US. Developed comprehensive unit tests to validate routing behavior for EU and APAC regions, and verified the solution in the eu-west-1 environment. Collaborated closely with a co-author to draft release notes and coordinate the rollout. The work emphasized backend development, AWS Bedrock API integration, and robust unit testing.