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
Local OpenAI-compatible proxies can return function arguments as parsed objects instead of JSON strings. Preserve object-shaped arguments directly and serialize them for streaming deltas so Write, Bash, and Edit tool calls keep the fields required by Anthropic tool validation.
Constraint: Local proxy implementations such as OneAPI/NewAPI may not preserve OpenAI's string-only arguments shape.
Rejected: Normalize every upstream response through JSON.stringify before parsing | loses already-valid object identity and leaves streaming object deltas vulnerable to [object Object].
Confidence: high
Scope-risk: narrow
Directive: Do not assume function.arguments is always a string on provider responses or stream deltas.
Tested: bun test src/server/__tests__/proxy-streaming.test.ts src/server/__tests__/proxy-transform.test.ts
Tested: bun run check:server
Tested: bun run check:native
Tested: bun run quality:pr
Tested: agent-browser with real Ollama qwen3:4b provider for Write/Bash/Edit and streaming Write
Not-tested: Real Windows OneAPI/NewAPI instance from the issue reporters was not available locally.
Add a protocol-translating reverse proxy that allows using OpenAI-compatible
API providers (DeepSeek, OpenRouter, Groq, etc.) with Claude Code.
The proxy intercepts Anthropic Messages API requests from the CLI, transforms
them to OpenAI Chat Completions or Responses API format, forwards to the
upstream provider, and transforms streaming/non-streaming responses back.
Key features:
- Request transform: Anthropic Messages → OpenAI Chat/Responses
- Response transform: OpenAI → Anthropic (streaming SSE + non-streaming)
- Provider-agnostic reasoning support (reasoning_content, thinking_blocks,
reasoning fields from DeepSeek, OpenAI o-series, GLM-5, Groq, etc.)
- Event queue pattern for correct Anthropic SSE event ordering
- Two-step test: ① connectivity check ② full proxy pipeline validation
- Desktop UI: API format selector, two-step test results display
- License attribution for cc-switch (MIT, Jason Young)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
