The eligibility gate in grokChatResponsesBridgeEligibility rejected any
structured content (arrays), including standard OpenAI image_url parts.
This forced image-bearing requests to fall back to raw Chat Completions
forwarding, where non-Composer models have no image bridge — silently
dropping the images or causing upstream errors.
Changes:
- Allow content arrays containing only text and image_url parts to pass
eligibility, so ChatCompletionsToResponses can convert them to
input_image parts that Grok vision models natively support.
- Force image-bearing requests to use Responses even when no prompt
cache identity is available, since the raw path cannot forward images
for non-Composer models.
- Add grokChatStructuredContentBridgeable helper with conservative
validation: unknown part types (e.g. input_audio) still fall back.
- Update tests: image_url content is now bridgeable; add cases for
text+image, text-only arrays, unknown parts, and empty arrays.
Add an opt-in first semantic output budget for native HTTP Responses, including response-header wait. Keep preamble and keepalive bytes non-semantic so a stalled account can fail over once without replaying its response IDs. Defaults remain disabled.
Related to #4201, #4185, and #4248. Complements the HTTP/2 dead-connection fix in #4207.
Adversarial re-verification found one more divergence from the
double-conversion chain: an upstream 200 with empty choices (or a nil
response) left stop_reason as an empty string, while the old chain
reports end_turn. Derive the fallback from the content blocks — the
guard never fires when choices exist, since every finish_reason maps to
a non-empty stop_reason.
Also strengthen the equivalence tests: compare tool_use Content[].Input
and tool_call Function.Arguments across bridges, and add an
empty-choices stop_reason parity case.
Adversarial review of the direct bridge found divergences from the
double-conversion chain it replaces; all are now aligned and covered by
tests that fail against the previous implementation:
- flush argument fragments buffered before a deferred tool announcement,
and announce name-less tools at finalize, so no tool arguments are lost
when upstreams stream arguments before the name
- fold text-only user array content into a single string; parts form only
when an image requires it (strict chat upstreams reject array content)
- drop tool_choice pointing at undeclared tools and unknown choice types
- treat cache_write_tokens/cache_creation_tokens as alternate spellings
(prefer write), not additive
- generate a response id when the upstream omits one
- derive stop_reason from blocks for content_filter/unknown finish reasons
- emit input_json_delta "{}" when a tool block closes without argument
deltas
Ambiguous idempotency-store failures can occur after the account transaction commits. Scope durable recovery markers to the authenticated admin, retain the operation key across reloads, and recover only an already committed copy without rerunning active work.
Constraint: Generic idempotent handlers may legitimately remain active while a recovery lookup is attempted
Rejected: Reclaim or rerun an in-progress duplicate request | can execute account creation concurrently
Rejected: Recover by source account and key alone | allows another admin to observe the committed copy
Confidence: high
Scope-risk: narrow
Reversibility: clean
Directive: Keep ambiguous-response recovery read-only and bind durable operation markers to the authenticated actor
Tested: Full Go unit suite, go vet, server build, integration-test compilation; frontend lint, typecheck, 1,030 Vitest tests, and production build
Not-tested: Docker-backed PostgreSQL integration runtime because Docker is unavailable
Related: Wei-Shaw/sub2api#1379
Related: Wei-Shaw/sub2api#2928
Wesley Liddick