build_user_content derived the data-URL subtype from the file extension
only (image_format = ext[1:]). An extensionless upload (e.g. a pasted
screenshot) has ext == "", producing "data:image/;base64,..." with an
empty subtype (invalid per RFC 2046) that vision/audio endpoints reject,
silently dropping the attachment. Fall back to the resolved MIME subtype
when the extension is missing; present extensions are unchanged.
_extract_entities used the ASCII-only class [A-Z][a-zA-Z]+ to pull name
entities from a query, so non-ASCII names were dropped ("İstanbul",
"Zürich" yielded nothing) or shredded ("São Paulo" -> only "Paulo"),
degrading query enhancement for non-English/accented searches. Match
Unicode words and keep the alphabetic, uppercase-initial ones; ASCII
behaviour (the word boundary already excludes camelCase mid-word
capitals) is unchanged.
Accept calendar datetime phrases such as "3pm tomorrow" by adding a time-first natural-language parser branch mirroring the reminder parser. Add regression coverage proving time-first forms match their existing day-first equivalents.
Miraç Duran