fix(server): allow browser SDK request headers through CORS preflight by lidge-jun · Pull Request #1778 · lidge-jun/opencodex

lidge-jun · 2026-08-15T13:26:30Z

Summary

The OpenAI and Anthropic browser SDKs send X-Stainless-* request headers describing runtime and retry state. The CORS preflight answered with a fixed Access-Control-Allow-Headers list that never mentioned them, so the browser blocked the real request before it was ever sent — every browser SDK client was unable to reach the proxy.

corsHeaders() now echoes the headers an already-allowed origin asked for, keeping the existing static list as the floor, and declares the dependency with Vary: Origin, Access-Control-Request-Headers.

The echo is gated on the origin check that already ran. It widens which headers an admitted caller may send, never which origins are admitted: a rejected origin is refused with 403 before any allow-list is built, and the preflight still carries no credential and produces no auth or account-pool side effect. Header names are normalized case-insensitively before de-duplication, so a caller re-requesting content-type cannot duplicate the entry.

Closes #1773

Verification

Run on the Linux validation host against this exact head:

bun test tests/server-auth.test.ts tests/server-live.test.ts tests/server-loopback-host-gate.test.ts tests/loopback-listener-admission.test.ts
142 pass, 0 fail, 859 expect() calls

bun x tsc --noEmit clean.

New regression table-drives /v1/messages, /v1/responses, and /v1/chat/completions: each must echo every requested Stainless header, preserve the static contract, avoid duplicating content-type, and set Vary. The rejected-origin case asserts 403 with no echoed header.

Checklist

Focused tests for the changed subsystem pass
bun x tsc --noEmit clean
No request bodies, keys, or account identifiers logged
Security boundary reviewed: origin admission is unchanged

Summary by CodeRabbit

Bug Fixes
- Improved CORS preflight handling for approved origins.
- Supports requested SDK headers while preventing duplicate headers.
- Rejects unauthorized origins with HTTP 403 responses.
- Added cache-safe response variation for origin and requested headers.
Tests
- Added coverage for CORS behavior across message, response, and chat completion endpoints.

The OpenAI and Anthropic browser SDKs send X-Stainless-* headers describing runtime and retry state. The preflight answered with a fixed allow-list that never mentioned them, so the browser blocked every request before it was sent and no browser SDK client could reach the proxy at all. Echo the requested headers for an origin that already passed the origin gate, keeping the static contract as the floor, and declare the dependency with Vary. The echo widens which headers an admitted caller may send, never which origins are admitted: a rejected origin is refused before any allow-list is built, and the preflight still carries no credential and no auth side effect. Closes #1773

coderabbitai · 2026-08-15T13:26:52Z

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📥 Commits

Reviewing files that changed from the base of the PR and between 906533b and f46094a.

📒 Files selected for processing (4)

devlog/_plan/260815_roadmap_closeout/000_source_capture_raw.txt
devlog/_plan/260815_roadmap_closeout/010_unit_overview.md
src/server/auth-cors.ts
tests/server-auth.test.ts

📝 Walkthrough

Walkthrough

The PR adds roadmap closeout records and updates server CORS handling. Authorized origins can receive requested preflight headers with case-insensitive deduplication. Tests cover Stainless SDK headers across three API routes and reject unauthorized origins.

Changes

Roadmap closeout and CORS handling

Layer / File(s)	Summary
Roadmap closeout records `devlog/_plan/260815_roadmap_closeout/000_source_capture_raw.txt`, `devlog/_plan/260815_roadmap_closeout/010_unit_overview.md`	The records document issue counts, merge and closure rules, CORS requirements, provider remediation plans, prioritization, validation evidence, execution status, and explicit holds.
Dynamic CORS preflight handling `src/server/auth-cors.ts`, `tests/server-auth.test.ts`	`allowedRequestHeaders` deduplicates requested headers and preserves additional header spelling. `corsHeaders` echoes them only for authorized origins and adds `Vary: Origin, Access-Control-Request-Headers`. Tests cover `/v1/messages`, `/v1/responses`, and `/v1/chat/completions`, including HTTP 403 responses for unauthorized origins.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

lidge-jun/opencodex#379: Shares CORS allow-list changes in src/server/auth-cors.ts and related tests.
lidge-jun/opencodex#850: Refines CORS origin and header handling in the same implementation and test files.
lidge-jun/opencodex#800: Uses corsHeaders for route-level CORS behavior.

Suggested labels: review-ready

Suggested reviewers: ingwannu, wibias

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Commit unit tests in branch codex/roadmap-closeout-260815

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github-actions · 2026-08-15T13:26:52Z

✅ Deterministic PR hygiene checks passed.

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chatgpt-codex-connector · 2026-08-15T13:29:53Z

+CRM 프로젝트 평가 요청
+인사 나누기
+김
+김병준


Remove personal account data from the tracked capture

The raw transcript includes the user's full name along with unrelated private ChatGPT history titles, so committing 000_source_capture_raw.txt publishes personal account data in the repository even though the automated privacy scan does not recognize names. Remove the raw UI capture or replace it with a narrowly redacted summary before this commit is pushed.

AGENTS.md reference: AGENTS.md:L281-L282

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chatgpt-codex-connector · 2026-08-15T13:29:53Z

+#1774 — Responses 전용 encrypted annotation 누출
+
+V2 spawn_agent의 tool schema에 있는 encrypted: true가 generic openai-chat upstream으로 그대로 전달될 때, provider가 필수 message argument를 비워 반환하는 controlled A/B 재현이 있다. provider 이름별 예외가 아니라 protocol-boundary schema sanitizer로 처리해야 한다. 


Move unfixed security triage out of devlog

This tracked _plan transcript records a controlled reproduction and patch strategy for unresolved defect #1774, with additional unresolved credential and routing boundary analysis later in the same file. Because devlog/ is public, pushing this commit publishes pre-disclosure working notes whose history is difficult to purge; keep the raw review in .tmp/ and commit only the fix and regression evidence once the affected defects are resolved.

AGENTS.md reference: AGENTS.md:L97-L104

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lidge-jun added 2 commits August 15, 2026 22:24

docs(devlog): capture the 260815 roadmap closeout unit map

ee22ae0

lidge-jun requested review from Ingwannu and Wibias as code owners August 15, 2026 13:26

lidge-jun merged commit 53130de into dev Aug 15, 2026
6 checks passed

lidge-jun mentioned this pull request Aug 15, 2026

[Bug]: CORS preflight rejects all browser SDK clients — Access-Control-Allow-Headers omits X-Stainless-* #1773

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github-actions Bot added the bug Something isn't working label Aug 15, 2026

chatgpt-codex-connector Bot reviewed Aug 15, 2026

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Wibias deleted the codex/roadmap-closeout-260815 branch August 15, 2026 19:57

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fix(server): allow browser SDK request headers through CORS preflight - #1778

fix(server): allow browser SDK request headers through CORS preflight#1778
lidge-jun merged 2 commits into
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		#1774 — Responses 전용 encrypted annotation 누출

		V2 spawn_agent의 tool schema에 있는 encrypted: true가 generic openai-chat upstream으로 그대로 전달될 때, provider가 필수 message argument를 비워 반환하는 controlled A/B 재현이 있다. provider 이름별 예외가 아니라 protocol-boundary schema sanitizer로 처리해야 한다.

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