12. Anthropic Messages Compatibility Endpoint#

POST /v1/messages — on top of the OpenAI-compatible pipeline, this additionally provides Anthropic Messages API protocol compatibility, drivable by the official Anthropic clients / SDKs, regardless of whether the underlying channel is actually OpenAI or Anthropic. Both non-streaming and streaming are supported (streaming is a server-synthesized Anthropic SSE event sequence).

Authentication notes#

Like every other endpoint, this one authenticates with Authorization: Bearer sk-... and does not accept Anthropic's default x-api-key header. When using the official Anthropic SDK, pass the key as a Bearer header (for example via the SDK's auth_token parameter or a custom request header) instead of the default api_key (which sends x-api-key).

Supported capabilities#

• Supported: plain-text messages, system prompts, max_tokens, stream, and other basic fields.
• Not supported: tools / tool_choice (function calling) and non-text content blocks (images and other multimodal content). Requests containing these fields return 400 immediately with an Anthropic-shaped error body — they are not silently dropped.
• All errors (auth, permissions, parameters) are uniformly returned in the Anthropic error shape.

curl http://183.240.79.21:52099/v1/messages \
  -H "Authorization: Bearer sk-你的YiTuoToken-Key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-3-5-sonnet-20241022",
    "max_tokens": 256,
    "system": "你是一个简洁的助手。",
    "messages": [
      { "role": "user", "content": "用一句话介绍你自己" }
    ]
  }'

For function calling / multimodal and other advanced capabilities, use /v1/chat/completions (OpenAI format) instead.