- Extract callUpstream helper to deduplicate ~30 lines between chatCompletions and responses
- Move HTML templates to internal/server/templates/ via go:embed (server.go 1749→1192 lines)
- Consolidate 4 copies of firstNonEmpty into util.FirstNonEmpty
- Extract chatStreamChunk named type shared by aggregateStream and aggregateResponsesStream
- Fix tool-call ordering: iterate sorted map keys instead of sequential 0..N
- Map upstream finish_reason to Responses API status (length/content_filter → incomplete)
- Surface /v1/models errors as 401/502 instead of silently returning empty 200
- Add Secure cookie flag via isTLSRequest helper
- forEachSSEChunk: use sseDataPayload parser, drop redundant json.Valid, distinguish bufio.ErrTooLong
- Fix StreamIdleTimout typo → StreamIdleTimeout
- sso.go: single Read → io.ReadAll(io.LimitReader), explicit unknown error fallback
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