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.
The desktop model picker now stores a session-scoped provider/model selection instead of relying on the global active provider. That selection is replayed on connect, passed into the CLI startup path, and preserved across turns until the user changes it again.
To make that true end-to-end, the server now restarts the session process when runtime selection changes, injects provider-scoped env for third-party providers, and routes proxy traffic by provider id. The selector UI was also tightened so provider grouping stays visible while the actual model choice remains readable.
Constraint: Different providers can expose the same model id, so chat runtime selection cannot be derived from model id alone
Constraint: A desktop session reuses one CLI subprocess across turns, so runtime changes must restart that process to take effect
Rejected: Keep using Settings active provider as the chat selector | conflates defaults with live session state and breaks overlapping models
Rejected: UI-only runtime switching without server restart | later turns would continue using the old CLI subprocess configuration
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Keep provider defaults and session runtime overrides separate, and preserve provider-scoped proxy routing when extending model selection surfaces
Tested: cd desktop && bun run lint
Tested: cd desktop && bun run test src/stores/chatStore.test.ts
Tested: cd desktop && bun run test src/__tests__/generalSettings.test.tsx
Tested: bun test src/server/__tests__/conversation-service.test.ts
Tested: bun test src/server/__tests__/conversations.test.ts
Tested: bun -e "await import('./src/server/services/titleService.ts'); await import('./src/server/ws/handler.ts')"
Not-tested: Real third-party provider round-trip from the desktop UI against a live upstream account
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>
