feat(server): add /v1/responses (OpenAI Responses API) for Codex CLI

Browse Source

Implements the Responses API endpoint that Codex CLI (and other modern
OpenAI tooling) speaks instead of /v1/chat/completions. The wire format
is documented in OpenAI's Responses API; this implementation has been
iterated against the Codex CLI binary's SSE parser shape until no
remaining schema gaps were found.

Request parsing (parse_responses_request, parse_responses_input):
- Accepts the typed input array (message, function_call,
  function_call_output, reasoning, custom_tool_call(_output),
  local_shell_call(_output), web_search_call(_output),
  tool_search_call(_output), image_generation_call(_output),
  compaction, context_compaction).
- Maps hosted-tool history to function_call/function_call_output so
  prior actions survive across turns; rejects unknown item types and
  non-completed status with 400 to avoid silent context loss.
- Strict content-array parsing: only string|null|array of recognized
  text blocks (input_text/output_text/text/summary_text/
  reasoning_text); rejects non-text modalities (input_image/file/
  audio) instead of accepting an empty prompt.
- Merges adjacent function_call items into the preceding assistant
  message so text + tool-call turns render as a single assistant
  block.
- Honors reasoning.effort (incl. "minimal"/"none") and gates
  reasoning summary surface on reasoning.summary opt-in.
- Rejects previous_response_id, conversation, and forced tool_choice
  explicitly (constrained decoding / persisted state not supported).

Output (responses_sse_*, responses_final_response):
- Emits the full streaming lifecycle: response.created,
  output_item.added/.done, reasoning_summary_part.added/.done,
  reasoning_summary_text.delta/.done, content_part.added/.done,
  output_text.delta/.done, function_call_arguments.delta/.done,
  response.completed.
- Branches the terminal event by finish reason: response.failed for
  errors and response.incomplete with reason "max_tokens" for length.
- Every event carries sequence_number; every output_text part carries
  annotations:[]; function_call output_item.added ships with an empty
  arguments string (full args arrive via function_call_arguments.done
  and output_item.done), and item ids are stable across added/done.
- Tracks whether </think> was actually observed so a truncated stream
  marks the reasoning item incomplete instead of "completed".
- Recovers gracefully when the DSML tool parse fails after the model
  was suppressed at the tool marker: the suppressed tail is flushed
  as additional output_text deltas so the streamed message matches
  output_item.done.

Tested by 25 rounds of /codex:adversarial-review against the same
client this is meant to feed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

...

This commit is contained in:

Audrey Tang

2026-05-12 06:45:02 -04:00

co-authored by Claude Opus 4.7

parent 3630e64ea2

commit bb697b3b5f

1 changed files with 1646 additions and 3 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download Patch File Download Diff File Expand all files Collapse all files

ds4_server.c

+1646 -3

File diff suppressed because it is too large Load Diff