Claude Sonnet 5.5

This page is generated from the upstream official OpenAPI documentation. Endpoints, parameters and examples match the official docs; brand and API domain are replaced with ModelFold.

Endpoint

POST /claude/v1/messages

Full URL: https://ai.modelfold.online/claude/v1/messages

Authentication: every request must include the Authorization: Bearer <API_KEY> header.

Streaming Support

When stream: true is set in the request, the API returns responses as server-sent events (SSE). Claude tool calling responses stream tool_use blocks and input_json_delta fragments.

Streaming Response Format:

• Content-Type: text/event-stream
• Event names include message_start, content_block_start, content_block_delta, message_delta, and message_stop
• Tool calls are emitted as tool_use content blocks
• Final stop reason is often tool_use for function-calling requests

Features

• Standard chat with messages.
• Function calling with tools and input_schema.
• Optional stream response with Claude events.
• Optional thinking flag (thinkingFlag).

Request Notes

• Put the current model name in the model field.
• Use messages for conversation history.
• Use tools to declare callable functions.
• Set stream to true for SSE output.

Authentication

Authentication: send Authorization: Bearer YOUR_API_KEY. Clients that send x-api-key (such as the Anthropic SDK) must set it to Bearer YOUR_API_KEY. anthropic-version is optional.

Request Parameters

Body (application/json)

Parameter	Type	Required	Description
model	string	Yes	Model id for this page, e.g. claude-sonnet-5-5. Available ids are listed by GET https://ai.modelfold.online/v1/anthropic/v1/models%60. Allowed values：claude-sonnet-5-5。 示例：claude-sonnet-5-5`。
messages	array<object>	Yes	Conversation messages in chronological order.
messages[].role	string	Yes	Message role. Allowed values：user / assistant。 示例：user。
messages[].content	`string	array<object>`	Yes
tools	array&lt;object&gt;	No	Optional callable tools. Each tool includes a name, description, and input_schema.
tools[].name	string	Yes	Function name. 示例：get_current_weather。
tools[].description	string	Yes	Human-readable function description. 示例：Get the current weather in a given location。
tools[].input_schema	object	Yes	JSON Schema for function parameters.
tools[].input_schema.type	string	No	Schema type. 示例：object。
tools[].input_schema.properties	object	No	Function parameter definitions.
tools[].input_schema.required	array&lt;string&gt;	No	Required parameter names.
thinkingFlag	boolean	No	Whether to enable thinking. 示例：true。
stream	boolean	No	If set to true, the response is returned as an SSE stream. Default：true。 示例：false。
max_tokens	number	No	Optional Claude output token limit. Leave empty to use the default of 4096. Default：4096。 示例：4096。

Request Example

curl -X POST "https://ai.modelfold.online/claude/v1/messages" \
  -H "Authorization: Bearer $MODELFOLD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "claude-sonnet-5-5",
  "messages": [
    {
      "role": "user",
      "content": "What is the weather like in Boston today?"
    }
  ],
  "tools": [
    {
      "name": "get_current_weather",
      "description": "Get the current weather in a given location",
      "input_schema": {
        "type": "object",
        "properties": {
          "location": {
            "type": "string",
            "description": "The city and state, e.g. Boston, MA"
          }
        },
        "required": [
          "location"
        ]
      }
    }
  ],
  "thinkingFlag": true,
  "stream": false,
  "max_tokens": 4096
}'

{
  "model": "claude-sonnet-5-5",
  "messages": [
    {
      "role": "user",
      "content": "What is the weather like in Boston today?"
    }
  ],
  "tools": [
    {
      "name": "get_current_weather",
      "description": "Get the current weather in a given location",
      "input_schema": {
        "type": "object",
        "properties": {
          "location": {
            "type": "string",
            "description": "The city and state, e.g. Boston, MA"
          }
        },
        "required": [
          "location"
        ]
      }
    }
  ],
  "thinkingFlag": true,
  "stream": false,
  "max_tokens": 4096
}

Response

200 — Request successful.

参数	类型	必填	说明
role	string	否	Returned message role 示例：assistant。
usage	object	否	Usage information returned in the response
usage.input_tokens	integer	否	Input token count 示例：600。
usage.output_tokens	integer	否	Output token count 示例：57。
usage.cache_creation_input_tokens	integer	否	Cache creation input token count 示例：0。
usage.cache_read_input_tokens	integer	否	Cache read input token count 示例：0。
usage.service_tier	string	否	Service tier 示例：standard。
stop_reason	string	否	Reason why generation stopped 示例：tool_use。
model	string	否	Actual model version returned in the response 示例：claude-opus-4-5-20251101。
id	string	否	Unique message identifier 示例：msg_01VSoxV4a8YWB3DBh9TdM63W。
credits_consumed	number	否	Credits consumed by the request 示例：0.25。
type	string	否	Top-level response object type 示例：message。
content	array<object>	否	Response content blocks
content[].input	object	否	Tool input arguments
content[].caller	object	否	Tool caller metadata
content[].caller.type	string	否	示例：direct。
content[].name	string	否	Tool name 示例：get_current_weather。
content[].id	string	否	Tool call identifier 示例：toolu_018gdqs2FHxrRjQHLZv1qvbF。
content[].type	string	否	Content block type 示例：tool_use。

{
  "role": "assistant",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "output_tokens": 57,
    "service_tier": "standard",
    "cache_creation_input_tokens": 0,
    "input_tokens": 600,
    "cache_read_input_tokens": 0,
    "inference_geo": "not_available"
  },
  "stop_reason": "tool_use",
  "model": "claude-sonnet-5-5",
  "id": "msg_01VSoxV4a8YWB3DBh9TdM63W",
  "credits_consumed": 0.14,
  "type": "message",
  "content": [
    {
      "input": {
        "location": "Beijing, China"
      },
      "caller": {
        "type": "direct"
      },
      "name": "get_current_weather",
      "id": "toolu_018gdqs2FHxrRjQHLZv1qvbF",
      "type": "tool_use"
    }
  ]
}

400 — Bad Request - Invalid request parameters

参数	类型	必填	说明
error	object	否	—
error.message	string	否	示例：Invalid request parameters。
error.type	string	否	示例：invalid_request_error。

{
  "error": {
    "message": "Invalid request parameters",
    "type": "invalid_request_error"
  }
}

401 — Unauthorized - Invalid or missing API key

参数	类型	必填	说明
error	object	否	—
error.message	string	否	示例：Invalid or missing API key。
error.type	string	否	示例：authentication_error。

{
  "error": {
    "message": "Invalid or missing API key",
    "type": "authentication_error"
  }
}