provider.Request.ResponseFormat was being silently dropped by the
openai translation layer (translate.go:translateRequest). The
upstream provider type and the openai-go SDK both supported it; the
adapter just never propagated it.
This is why Move 1 (set ResponseFormat=ResponseJSON in the SLM
classifier) produced zero observable change: the field made it from
the classifier into provider.Request but stopped at the OpenAI
translation step. The ollama backend (used via the OpenAI-compatible
endpoint) therefore never received format=json_object and kept
emitting free-form prose, which the classifier's downstream JSON
parser duly rejected — 50 fallbacks in a row across two model swaps.
Translate provider.ResponseJSON to oai.ResponseFormatJSONObjectParam
and provider.ResponseText to oai.ResponseFormatTextParam; leave the
union zero-valued when the caller didn't set ResponseFormat so the
SDK omits the field per its omitzero tag. Three table cases cover
the json / text / unset paths.
Affects ollama, llama.cpp, llamafile, and any other backend reached
via openaicompat — all run through openai.translateRequest.
vikingowl
c065a2dea7