The user supplied the failing ISBNs: 9781883937386 (The Hittite Warrior)
and 9781883937676 (Shadow Hawk), both Bethlehem Books. Both resolve
against the source the app already queries — title, author, publisher,
page count, cover art — and both real responses parse correctly through
the app's own OpenLibraryClient. Captured as fixtures with a regression
test, because these are the specific books that motivated the research.
That kills the coverage hypothesis for these two and demotes Harvard,
which holds neither: its 93% in the sample table is inflated by
construction (the sample was drawn from Harvard) and misleading in
exactly the direction that matters — it is a research library and does
not carry small-press children's historical fiction.
The failure is upstream of the metadata sources. Documented the three
candidates; the leading one is that the barcode never decoded into a
valid ISBN-13, which ScanCodeFilter drops silently with no UI feedback
whatsoever. Revised the recommendation accordingly: make the app say
what happened before adding any source.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDcPottghJXEvfYKqFM7zf
Spriteandclaude
1ba22a9f36