DeriveUpstreamEndpoint maps every OpenAI-platform request to /v1/responses, but
API-key accounts whose upstream only speaks Chat Completions
(!ShouldUseResponsesAPI) are forwarded directly to /v1/chat/completions. The
messages, responses and cyber-policy recording sites derived the endpoint via the
bare GetUpstreamEndpoint, so usage/ops records mislabeled those requests as
/v1/responses. Generalize the existing resolveRawCCUpstreamEndpoint into
resolveOpenAIUpstreamEndpoint and use it at every OpenAI recording site, matching
the already-correct chat-completions client path.
Service layer writes a complete JSON error response then returns error.
Handler's ensureForwardErrorResponse couldn't distinguish this from
"no response written" and appended an SSE event, corrupting the body.
Use gin.Context flag: service marks MarkResponseCommitted(c) after
writing, ensureForwardErrorResponse checks IsResponseCommitted(c)
and skips. Zero function signature changes, zero error wrapping.
Keep large gateway payloads as raw body ranges and bind OpenAI parsed-body caches to the body bytes so failover and mapping do not reuse stale mutable state.
Case B: when a slot wait flushes SSE ping comments first (Writer.Written
becomes true), the previous ensureForwardErrorResponse short-circuited
on `c.Writer.Written()` and returned false without notifying the client.
Subsequent upstream errors (http2 timeout, stream INTERNAL_ERROR, etc.)
produced silent EOF; Codex CLI reported "stream closed before
response.completed" just like the user-slot timeout case.
Remove the Written() early return; coerce streamStarted to true when
Writer has already been written to, and let handleStreamingAwareError
walk the existing logic — which now (thanks to the previous commits)
emits a protocol-compliant response.failed for /responses paths and the
legacy `event: error` for others.
Update tests that previously asserted "do not override written response":
the new contract is to *append* an SSE terminal frame so the client sees
a clean close instead of EOF. recoverResponsesPanic inherits this fix.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
The first revision compared GetInboundEndpoint(c) against EndpointResponses
("/v1/responses"). NormalizeInboundEndpoint only recognizes paths that
contain the literal "/v1/responses" substring, but the project actually
registers six /responses routes — three of which (top-level
r.POST("/responses", ...) and codexDirect's "/backend-api/codex/responses")
have FullPath values without the "/v1" prefix and therefore fall through
to the default branch.
Codex CLI users targeting the bare /responses route at the production
deployment (observed 2026-05-24 ~11:05 UTC, user 16) never reached the
new writeResponsesFailedSSE path: the endpoint check was false, the
legacy `event: error` frame fired, and the strict SDK kept reporting
"stream closed before response.completed".
Replace the strict equality check with inboundIsResponses(c), which
uses suffix detection on FullPath (falling back to URL.Path when
FullPath is empty in test fixtures) and covers all six route variants:
/v1/responses[/...]
/responses[/...]
/backend-api/codex/responses[/...]
Add test table covering all routes plus negative cases.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
When /v1/responses streaming hits the user/account concurrency wait, the
wait loop sends SSE ping comments to keep the connection alive, which
flushes HTTP 200 + headers. If the wait then times out (or any other
post-flush error fires), handleStreamingAwareError previously emitted a
generic `event: error` frame. Codex CLI requires the stream to end with
a Responses terminal event (response.completed/failed/incomplete/cancelled),
so it reports "stream closed before response.completed" and the user-facing
rate-limit intent is lost.
This change detects inbound = /v1/responses in both handleStreamingAwareError
implementations and emits a protocol-compliant response.failed event whose
field set mirrors apicompat.makeResponsesCompletedEvent
(id/object/model/status/output/error). The synthetic id reuses
ctxkey.RequestID so client errors can be grepped against server logs.
sequence_number is intentionally omitted to preserve monotonicity on streams
that already emitted real events.
Other inbound endpoints (/v1/chat/completions, /v1/messages) keep their
legacy formats untouched.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
