USR369 is uploading a phone-local "old zips ref" folder (subfolders extra, v0.0-v1.5, each holding zips of old CAI system MDs) to systems/old-zips-ref/ (his choice, outside backups/ so AI sessions can actually read it — backups/ is permanently 403 per SOP-OLD-ZIPS-ARCHIVE.md). Built old-zips-search-api.php at systems/ root: action=ping (dir/zip/index status), action=reindex (POST — walks old-zips-ref/, extracts any zip via ZipArchive to old-zips-ref/_extracted/, builds a lightweight JSON index of extracted files), action=search (query+optional version filter, greps indexed text-like files, returns file+snippet), action=list_versions. Reused real boilerplate pulled via file-reader.php from 40-server/data/api.php (auth-lib.php require, cai_time()/cai_now(), token check, JSON envelope) rather than guessing from the SOP summary alone, per D-SEARCH-FIRST. Deployed via file_write_web.php, confirmed full server path is /home/yttcooyc/public_html/systems/old-zips-search-api.php (also resolves the open question from the X-plore FTP-root screenshot earlier this session — public_html IS the live docroot, so the root-level systems/ and yttcom.net/ folders seen sitting outside public_html in that screenshot are NOT the live ones).