Senior-level proficiency (6+ years) in Rust, with a strong track record of shipping production code. Experience contributing to or leading open-source projects. Familiarity with workflow engines, scientific computing, or large-scale computation. Ability to work with Rust crates for lexing, parsing, validating, linting, formatting, testing, and executing domain-specific languages. Strong skills in API design and specification development. Experience using GitHub for project planning and collaboration.