[HAYDEN-OAI]

Summary

• Reject named SSE event: error frames as typed APIErrors instead of yielding flat provider failures as successful Chat Completions, Responses, and Assistants stream events.
• Preserve nested provider errors, request headers and request IDs, cancellation, ordinary named events, Assistant event envelopes, completion sentinels, and private malformed-event diagnostics.
• Remove the unreachable error check from the Assistant-only branch and add 19 public-API and exported-stream regression cases.

Validation

• Regression-first on untouched main: all three actual new OpenAI({ fetch }) public streaming APIs and both exported event-synthesis modes incorrectly fulfilled before the fix.
• OPENAI_TEST_SUITE=unit pnpm test -- --maxWorkers=6 — 3,531 handwritten tests passed.
• OPENAI_TEST_SUITE=generated pnpm test -- --runInBand — 559 generated tests passed.
• pnpm lint — zero errors and warnings.
• pnpm exec tsc --pretty false; pnpm build.
• Published source type-checked with TypeScript 4.9 and 6.
• pnpm exec publint dist; packed-package CommonJS, ESM, and 267 source checks passed on Node 22.23.2 and 26.7.0.
• Dedicated 19-case streaming regression passed on Node 22 and Node 26.

[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 8.525s for Node SDK PR #2409.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	89ms
tests/chat-completions-create.test.ts	✅ Passed	185ms
tests/chat-completions-stream.test.ts	✅ Passed	100ms
tests/files-content-binary.test.ts	✅ Passed	111ms
tests/files-create-multipart.test.ts	✅ Passed	107ms
tests/files-list-pagination.test.ts	✅ Passed	109ms
tests/initialize-config.test.ts	✅ Passed	98ms
tests/instance-isolation.test.ts	✅ Passed	85ms
tests/models-list.test.ts	✅ Passed	99ms
tests/responses-background-lifecycle.test.ts	✅ Passed	171ms
tests/responses-body-method-errors.test.ts	✅ Passed	242ms
tests/responses-cancel-timeout.test.ts	✅ Passed	169ms
tests/responses-cancel.test.ts	✅ Passed	165ms
tests/responses-compact-retries.test.ts	✅ Passed	178ms
tests/responses-compact.test.ts	✅ Passed	159ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	93ms
tests/responses-create-advanced.test.ts	✅ Passed	146ms
tests/responses-create-disconnect.test.ts	✅ Passed	1.158s
tests/responses-create-errors.test.ts	✅ Passed	161ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	91ms
tests/responses-create-retries.test.ts	✅ Passed	116ms
tests/responses-create-stream-failures.test.ts	✅ Passed	170ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	2.124s
tests/responses-create-stream-wire.test.ts	✅ Passed	2.092s
tests/responses-create-stream.test.ts	✅ Passed	64ms
tests/responses-create-terminal-states.test.ts	✅ Passed	160ms
tests/responses-create-timeout.test.ts	✅ Passed	175ms
tests/responses-create.test.ts	✅ Passed	109ms
tests/responses-delete.test.ts	✅ Passed	85ms
tests/responses-input-items-errors.test.ts	✅ Passed	131ms
tests/responses-input-items-list.test.ts	✅ Passed	136ms
tests/responses-input-items-options.test.ts	✅ Passed	79ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	176ms
tests/responses-input-tokens-count.test.ts	✅ Passed	151ms
tests/responses-malformed-inputs.test.ts	✅ Passed	1.679s
tests/responses-not-found-errors.test.ts	✅ Passed	191ms
tests/responses-parse.test.ts	✅ Passed	124ms
tests/responses-retrieve-retries.test.ts	✅ Passed	236ms
tests/responses-retrieve.test.ts	✅ Passed	204ms
tests/responses-stored-method-errors.test.ts	✅ Passed	470ms
tests/retry-behavior.test.ts	✅ Passed	3.009s
tests/sdk-error-shape.test.ts	✅ Passed	225ms

View OkTest run #32196970553

_{SDK merge (3798bdfa5590) · head (44b730c36bbf) · base (2097ba0902cc) · OkTest (7e7850017529)}

[jbeckwith-oai]

Independent two-pass review: named SSE provider errors are correctly converted into APIError while preserving nested error behavior, response metadata, request IDs, assistant envelopes, cancellation, and sanitized malformed-event diagnostics. No actionable findings.