Choosing an Endpoint
The Turing Platform offers three conversational core endpoints. If you just want to see code, pick the first one. If you need to leverage vendor-specific capabilities to their fullest, you may need to use the native protocol.
Quick Decision Tree
Endpoint Comparison
| Chat Completions | Messages (Anthropic) | Responses (OpenAI) | |
|---|---|---|---|
| URL | /v1/chat/completions | /v1/messages | /v1/responses |
| Protocol | OpenAI Chat | Anthropic native | OpenAI next-gen |
| Request fields | messages | messages + max_tokens required | input (not messages) |
| Response structure | choices[].message | content[] block array | output[] polymorphic array |
| Cross-vendor | ✅ Primary (OpenAI/Claude/Gemini/Qwen/DeepSeek...) | ⚠ Full Claude lineup + select domestic models (Qwen/DeepSeek/GLM/Kimi/MiniMax/Doubao Seed 2.1); refer to the endpoint column in the model list | ⚠ GPT-5 / o series + select domestic models (Doubao Seed, Qwen, DeepSeek, GLM 5.x, Kimi); refer to the endpoint column in the model list |
| Prompt caching (Claude fine-grained) | ⚠ Available but simplified | ✅ Native cache_control | — |
| Extended Thinking (Claude) | ⚠ Via extra_body | ✅ Native thinking field | — |
| Reasoning (GPT-5/o) | ⚠ Via extra_body reasoning_effort | — | ✅ Native reasoning field |
| Stateful reasoning (GPT-5.x) | ❌ | — | ✅ tags: ["stateful"] |
| MCP tool connector | ❌ | ❌ | ✅ |
| Streaming event granularity | Coarse (choices[0].delta) | Fine (content_block_delta / text_delta / ...) | Finest (response.output_text.delta, etc.) |
| Turing extensions | ✅ turing_options | ✅ turing_options | ✅ turing_options + tags |
| Recommended for | 99% of use cases | Deep Claude customization | Deep GPT-5/o reasoning |
Summary
- Choose Chat Completions in the vast majority of cases: cross-vendor, largest ecosystem, switch models by changing a single string.
- Use Messages only when you explicitly need Claude's native block structure or finer-grained caching.
- Use Responses only when you explicitly need the GPT-5/o series' reasoning + stateful + MCP combination.