Single-source codebase decomposition: scans a project scope, builds the module dependency graph, counts LOC by language, computes skip patterns (caller-supplied ∪ .gitignore ∪ baseline), and (when grouping is required) produces topology groupings with L3 quality validation. One skill owns ProjectProfile JSON, grouping protocols, and quality gates.
Install
npx skills add microsoft/github-copilot-modernization --skill project-decompositionnpx skills add microsoft/github-copilot-modernization --skill project-decomposition -a claude-code -gnpx skills add microsoft/github-copilot-modernization --skill project-decomposition -a codex -ggemini skills install https://github.com/microsoft/github-copilot-modernization.git --path plugins/github-copilot-modernization/skills/project-decompositiongh skill install microsoft/github-copilot-modernization project-decompositiongit clone --depth 1 https://github.com/microsoft/github-copilot-modernization /tmp/microsoft__github-copilot-modernization
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/microsoft__github-copilot-modernization/plugins/github-copilot-modernization/skills/project-decomposition ~/.claude/skills/project-decomposition # Claude Code
cp -R /tmp/microsoft__github-copilot-modernization/plugins/github-copilot-modernization/skills/project-decomposition ~/.agents/skills/project-decomposition # Codex, Cursor, Gemini CLI, Copilot, OpenCode