Measured on a real Leonardo load against the local platform stack:
per-lib sync-stack POSTs : 174-200 -> 0
batch sync-stacks POSTs : 0 -> 1 (216 stacks in one request)
file GETs negotiating ydoc: 0 -> 107 of 133
Lib resolve: syncedScopeLibsSource now resolves every stack up front through
the shared paged batch client and feeds them to the per-lib sources, which skip
their own POST on a hit. Best-effort throughout — a failure (older backend
without the route, a network blip) leaves the map empty and every lib resolves
exactly as before, so this can only remove requests, never break a load. A
batched `null` is recorded as "backend says unresolvable" so a stale pin isn't
then retried one-by-one.
File downloads: fetchFileBytes sends Accept: application/x-pcbjam-ydoc and
converts client-side with the converters shared already exports, moving the
per-request materialize cost off the metered Worker. A backend that doesn't
negotiate answers with text and the branch never fires; a ydoc we fail to
convert re-fetches without negotiating rather than making the file
undownloadable.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0137pGo8W7asomGUTRMB7RzM
ad777bcbba