Three fidelity gaps where the mock answered a request differently from the
API it stands in for:
- The usage chunk was emitted on every stream. The real API sends it only
when stream_options.include_usage is set, so a caller that did not opt in
had to skip a trailing chunk with an empty choices array. stream_options
is now a typed model, which also rejects a non-boolean include_usage
instead of reading it as truthy.
- A fixed-length tuple is prefixItems with no items, which is what Pydantic
emits for tuple[str, int]. Reading only items returned [], failing the
minItems the same schema carries — the silent-empty failure schema_gen
exists to avoid.
- A zero or negative dimensions was silently replaced with 1536, answering
a bad request with a plausible-looking vector rather than a 400.
Three further deviations from JSON Schema are left in place and documented
where they occur: allOf merges properties first-wins, oneOf is treated as
anyOf, and string pattern is ignored. None is reachable from a Honcho
response model — no model emits prefixItems or oneOf, and the only pattern
constraints are on API request models — and each fix costs more than the
unreachable path is worth.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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