5+ years writing production Python. You should be comfortable in a 5K+ line Python codebase, idiomatic with `typing`, `pathlib`, `subprocess`, `pytest`, and the subtleties of mocking at the import-site vs. the source-site (this will come up).
Deep familiarity with Docker, docker-compose, and the Dev Containers specification. You should be able to read a `devcontainer.json` plus its referenced `docker-compose.yml` and predict exactly which bind-mounts, setting variables, and lifecycle hooks will land inside the resulting container.
Comfortable across macOS, Linux, and Windows as both a user and a developer. Cross-platform shell quirks (PowerShell vs. bash, path-separator handling, symlink semantics, NTFS junctions vs. POSIX links) should be old friends,
not surprises.
Strong Git: worktrees, hooks, submodules, the difference between `git rev-parse --git-common-dir` and `--git-dir`, and exactly what `git add -A` will silently sweep into a commit.
A working understanding of at least one of: large C++ codebases (CMake/Bazel, distcc/ccache, NFS-backed build artifacts) or large Java codebases (Maven/Gradle, IDE indexing, build caches). You will not write application code, but you will need to read it and understand why a build is slow inside the container.