tools/corpus_engine.py indexes pages and headings once for orphans, links, Type/Status/Design refs, doorway bounds, and retired-authority language. wiki_gate.sh and corpus_gate.sh stay as entrypoints; fixture suite covers orphan, broken link, missing Design anchor, and bad Status. Docs path runs fixtures; gates fail clearly without python3. Defense: Implements wiki/process/agent-scale.md slice E (fast corpus/wiki engine with fixtures and stable script names).