Use when starting any non-trivial change, investigating a bug, or working in unfamiliar code - before the first line is written. Also use for pure investigation with no change planned yet - "dig into this", "figure out why", "sometimes the export is empty", intermittent errors after a deploy. Encodes the ground-first discipline: map the real code and data, quote evidence, never guess conventions.
Install
npx skills add riekelt/principal-engineer --skill grounding-before-codingnpx skills add riekelt/principal-engineer --skill grounding-before-coding -a claude-code -gnpx skills add riekelt/principal-engineer --skill grounding-before-coding -a codex -ggemini skills install https://github.com/riekelt/principal-engineer.git --path plugins/principal-engineer/skills/grounding-before-codinggh skill install riekelt/principal-engineer grounding-before-codinggit clone --depth 1 https://github.com/riekelt/principal-engineer /tmp/riekelt__principal-engineer
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/riekelt__principal-engineer/plugins/principal-engineer/skills/grounding-before-coding ~/.claude/skills/grounding-before-coding # Claude Code
cp -R /tmp/riekelt__principal-engineer/plugins/principal-engineer/skills/grounding-before-coding ~/.agents/skills/grounding-before-coding # Codex, Cursor, Gemini CLI, Copilot, OpenCode