Integer range: integers are stored as 64-bit signed (i64). Values outside [-9223372036854775808, 9223372036854775807] are loaded as strings.
Underscore separators: 1_000 is not parsed as an integer — it is loaded as the string "1_000" (and round-tripped faithfully as such).
Blank line cap: at most 255 blank lines before any entry are tracked; runs longer than that are clamped to 255 on load.
Block only by default: the emitter writes block-style YAML. Flow containers ({...} / [...]) from the source are preserved if they were already flow-style, but there is no option to force everything to flow on dump.
Memory per document: each individual document must fit in memory. load / load_all stream from IO in 8 KB chunks so the raw source text is not buffered as a whole, but the resulting Python objects still live in memory. For large multi-document streams use iter_load_all / iter_loads_all to process one document at a time without accumulating the full list.
YAML version: the scanner implements YAML 1.1 boolean/null coercion (yes/no/on/off/~). Most YAML 1.2-only documents load correctly, but inputs that rely on strict YAML 1.2 semantics may differ.