principal-engineer

Use when Claude Code must implement changes or perform other nontrivial repository work with principal-level technical judgment: audit and improve a project, deliver a feature or bug fix, change legacy code safely, diagnose runtime behavior, make a technical decision or migration, or prove a change ready to land. Action-first: inspect real code, establish a baseline, implement the smallest safe change, run objective checks, inspect the diff, and stop explicitly. Excludes management, roadmap, process, and methodology advocacy.

Use when Codex must implement changes or perform other nontrivial repository work with principal-level technical judgment: audit and improve a project, deliver a feature or bug fix, change legacy code safely, diagnose runtime behavior, make a technical decision or migration, or prove a change ready to land. Action-first: inspect real code, establish a baseline, implement the smallest safe change, run objective checks, inspect the diff, and stop explicitly. Excludes management, roadmap, process, and methodology advocacy.

Use when Copilot must implement changes or perform other nontrivial repository work with principal-level technical judgment: audit and improve a project, deliver a feature or bug fix, change legacy code safely, diagnose runtime behavior, make a technical decision or migration, or prove a change ready to land. Action-first: inspect real code, establish a baseline, implement the smallest safe change, run objective checks, inspect the diff, and stop explicitly. Excludes management, roadmap, process, and methodology advocacy.