ubiquitous-language

Build or refresh the project's ubiquitous language glossary — one markdown file per business concept at `.plans/domain/<Concept>.md` plus a `_index.md`. Mines grep-based signals (class names, enum values, interface names, domain-event names, BDD scenario names, validator rules) and applies a four-gate filter to keep only genuine business concepts. Optional interactive interview phase to refine definitions and capture behavior (state transitions, invariants, synonyms to avoid). Language-agnostic — works for JS/TS, C#, Java, Python, Go, or any mix. Use whenever the user says "build the glossary", "extract domain terms", "document the ubiquitous language", "what are the domain concepts", or when domain-review surfaces pervasive terminology inconsistency (3+ names for the same concept).