improve-arch

## When to invoke Use when asked to "improve architecture", "find refactoring opportunities", "deepen modules", "consolidate tightly-coupled modules", or to make a codebase more testable and AI-navigable. ## Preamble ```bash eval "$(~/.vibestack/bin/vibe-slug 2>/dev/null)" 2>/dev/null || SLUG="unknown" _LEARN_FILE="${VIBESTACK_HOME:-$HOME/.vibestack}/projects/${SLUG:-unknown}/learnings.jsonl" if [ -f "$_LEARN_FILE" ]; then _LEARN_COUNT=$(wc -l < "$_LEARN_FILE" 2>/dev/null | tr -d ' ') echo "LEARNINGS: $_LEARN_COUNT entries loaded" if [ "$_LEARN_COUNT" -gt 5 ] 2>/dev/null; then ~/.vibestack/bin/vibe-learnings-search --limit 5 2>/dev/null || true fi else echo "LEARNINGS: none yet" fi ``` {{include lib/snippets/session-host.md}} {{include lib/snippets/decision-brief.md}} {{include lib/snippets/working-protocols.md}} {{include lib/snippets/state-protocols.md}} # Improve Codebase Architecture Surface architectural friction and propose **deepening opportunities** — refactors that turn shallow modules into deep ones. The aim is testability and AI-navigability. ## Glossary Use these terms exactly in every suggestion. Consistent language is the point — don't drift into "component," "service," "API," or "boundary." Full definitions in [LANGUAGE.md](LANGUAGE.md). - **Module** — anything with an interface and an implementation (function, class, package, slice). - **Interface** — everything a caller must know to use the module: types, invariants, error modes, ord...