ChatGPT Codex requires streamed Responses API requests, including hidden non-chat paths such as title generation. Keep the OAuth adapter streaming upstream while preserving JSON responses for non-streaming Anthropic callers, and route ChatGPT Official titles through the OAuth Codex endpoint.
Constraint: ChatGPT Codex rejects non-streaming requests with HTTP 400
Rejected: Disable AI title generation for ChatGPT OAuth | would leave first-session metadata degraded
Confidence: high
Scope-risk: narrow
Tested: bun test src/services/openaiAuth/fetch.test.ts
Tested: bun test src/server/__tests__/title-service.test.ts
Tested: bun run check:server
Tested: git diff --check
Not-tested: Live ChatGPT OAuth account round trip after remote build
a159ee3511