Adopt a single logging approach across commands and services: - **Never use `print`/direct `FileHandle.standardError.write` in production code** for user-facing or diagnostic messages. Use `Logger`. - **Plumb and reuse the existing logger**: - In `AsyncLoggableCommand`, use the provided `log`—don’t create a redundant logger. - In utilities/helpers, accept a `log: Logger` (or `log: Logger?` when optional) from the caller; don’t do unconditional stderr output inside the helper. - **Use structured logging**: prefer `metadata` dictionaries over interpolating values into the message. - Example pattern: ```swift log.warning( "failed to load container", metadata: ["path": dir.path, "error": String(describing: error)] ) ``` - **Choose appropriate levels for stderr/normal flows**: avoid logging non-error conditions to stderr; reserve `warning/error` for actionable issues, and use `debug/trace` for noisy entry/exit or busy calls. - **Keep test diagnostics real**: when cleanup fails, log enough details to diagnose (name, error, stdout/stderr/status) rather than retrying in a way that hides the root cause. Applying this consistently will keep stderr output clean, make logs machine-parseable, and ensure logging behavior follows configured verbosity (e.g., `--debug` should increase log level via the logger/handler, not by adding new ad-hoc prints).