Claude Messages API for AI Chat and Text Generation

POST /gw_llm_power/v1/messages — Send messages using the Anthropic Claude protocol. Supports Claude and GPT models with native Claude request format.

The Claude Messages API lets you interact with Claude and GPT models using the native Anthropic request format. It is fully compatible with the official Anthropic SDK and documentation, so you can point your existing Anthropic integrations at GlobalAI OPC with minimal changes.

Base URL: http://apillm.globalaiopc.com/gw_llm_power

Endpoint: POST /v1/messages

Authentication

Authenticate every request using the Authorization header with your API key:

Authorization: Bearer YOUR_API_KEY
Content-Type: application/json

Supported Models

Claude Models

Standard	-official	-hc	-fd
claude-haiku-4-5	claude-haiku-4-5-official	claude-haiku-4-5-hc	claude-haiku-4-5-fd
claude-opus-4-5	claude-opus-4-5-official	claude-opus-4-5-hc	claude-opus-4-5-fd
claude-opus-4-6	claude-opus-4-6-official	claude-opus-4-6-hc	claude-opus-4-6-fd
claude-opus-4-7	claude-opus-4-7-official	claude-opus-4-7-hc	claude-opus-4-7-fd
claude-sonnet-4-5	claude-sonnet-4-5-official	claude-sonnet-4-5-hc	claude-sonnet-4-5-fd
claude-sonnet-4-6	claude-sonnet-4-6-official	claude-sonnet-4-6-hc	claude-sonnet-4-6-fd

GPT Models (via Claude Protocol)

GPT models are also accessible through the Claude Messages API using the same request format.

Standard	-official	-hc	-fd	-low
gpt-5.4	gpt-5.4-official	gpt-5.4-hc	gpt-5.4-fd	gpt-5.4-low
gpt-5.5	gpt-5.5-official	gpt-5.5-hc	gpt-5.5-fd	gpt-5.5-low

GPT models accessed through this endpoint do not support image analysis. For image input with GPT models, use the OpenAI Chat API endpoint instead.

Model Suffix Reference

Suffix	Description
(none)	Standard version
-official	Official version
-hc	High-quality pool (AWS or premium account pool)
-fd	Proxy pool / mixed account pool
-low	Budget version

Request Parameters

model · string · required

The name of the model to use. For example: claude-opus-4-6, claude-sonnet-4-5, or gpt-5.5.

max_tokens · integer · required

The maximum number of tokens the model may generate in its response. This field is required by the Claude protocol.

messages · array · required

An array of message objects representing the conversation history, following the Claude Messages protocol.

messages[].role · string · required

The role of the message author. Accepted values: user or assistant.

messages[].content · string | array · required

The content of the message. Pass a plain text string for standard text input, or a Claude native content block array for multimodal input.

system · string

An optional system prompt that sets the context and behavior for the model throughout the conversation.

stream · boolean

When set to true, the response is returned as a stream of Claude-style SSE events.

temperature · number

Controls the randomness of the model’s output. Lower values produce more focused, deterministic responses; higher values produce more varied output.

Response Fields

id · string

A unique identifier for the message response.

type · string

The type of the returned object. Always message.

role · string

The role of the generated message. Always assistant.

content[].type · string

The type of the content block. Typically text for standard text responses.

content[].text · string

The text content generated by the model.

stop_reason · string

The reason the model stopped generating. Common values include end_turn (natural end) and max_tokens (token limit reached).

usage.input_tokens · integer

The number of tokens in the input messages and system prompt.

usage.output_tokens · integer

The number of tokens in the generated response.

Code Examples

cURL

curl -X POST http://apillm.globalaiopc.com/gw_llm_power/v1/messages \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-opus-4-6",
    "max_tokens": 1024,
    "system": "You are a professional writing assistant.",
    "messages": [
      {"role": "user", "content": "Write a product description for a coffee maker."}
    ]
  }'

Example Response

{
  "id": "msg_01ABC123",
  "type": "message",
  "role": "assistant",
  "content": [
    {
      "type": "text",
      "text": "Introducing the BrewMaster Pro — your perfect morning companion. With precision temperature control and a 12-cup capacity, it delivers rich, barista-quality coffee every time."
    }
  ],
  "model": "claude-opus-4-6",
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 18,
    "output_tokens": 42
  }
}

This endpoint is fully compatible with the Anthropic Messages API protocol. For complete details on request options — including extended thinking, tool use, and vision — refer to the Anthropic Messages API documentation.