responsesInputToMessages unmarshaled function_call.arguments and
function_call_output.output as bare strings, silently dropping the
value when it arrived as an object or content-parts array. This
caused the model to lose tool-call context in multi-turn
conversations, increasing the likelihood of malformed tool-call JSON.
Add rawJSONToString (re-encodes non-string values as JSON strings)
and outputToString (extracts text from content-parts arrays, re-encodes
other non-string values). Add 3 regression tests covering object
arguments, array output, and object output.
Translate Responses API requests (input→messages, instructions→system,
max_output_tokens→max_tokens, text.format→response_format, flat tools→nested
{function:{…}}) to upstream chat/completions, then convert responses back to
Responses format (streaming SSE event lifecycle + non-streaming JSON).
Verified against OpenAI migration guide and Python SDK Response model:
- Echo back required fields parallel_tool_calls/tool_choice/tools
- Include content:[] in reasoning items, logprobs:[] in output_text parts
- Support function_call/function_call_output multi-turn input items
- Map usage fields prompt_tokens→input_tokens, completion_tokens→output_tokens
m1saka