Chat

Anthropic Messages

Use this endpoint when your client expects Anthropic’s Messages request and response shape, such as Claude-compatible SDKs or tools configured with a custom Anthropic base URL.

The request body, supported model values, streaming flag, top-level system field, and optional tool fields are defined in the schema below. Official protocol reference: Anthropic Messages API.

Errors use this endpoint’s protocol envelope and an HTTP error status, including failures rejected by the gateway. See Error handling for status codes, quota errors, and streaming failures.

POST

messages

Anthropic Messages

curl --request POST \
  --url https://api.linkmodel.ai/v1/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "claude-fable-5",
  "messages": [
    {
      "role": "user",
      "content": "Hello, who are you?"
    }
  ],
  "max_tokens": 1024,
  "system": "You are a helpful assistant.",
  "stream": false,
  "stop_sequences": [
    "<string>"
  ],
  "tools": [
    {}
  ],
  "tool_choice": {},
  "thinking": {}
}
'

import requests

url = "https://api.linkmodel.ai/v1/messages"

payload = {
    "model": "claude-fable-5",
    "messages": [
        {
            "role": "user",
            "content": "Hello, who are you?"
        }
    ],
    "max_tokens": 1024,
    "system": "You are a helpful assistant.",
    "stream": False,
    "stop_sequences": ["<string>"],
    "tools": [{}],
    "tool_choice": {},
    "thinking": {}
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'claude-fable-5',
    messages: [{role: 'user', content: 'Hello, who are you?'}],
    max_tokens: 1024,
    system: 'You are a helpful assistant.',
    stream: false,
    stop_sequences: ['<string>'],
    tools: [{}],
    tool_choice: {},
    thinking: {}
  })
};

fetch('https://api.linkmodel.ai/v1/messages', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.linkmodel.ai/v1/messages",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => 'claude-fable-5',
    'messages' => [
        [
                'role' => 'user',
                'content' => 'Hello, who are you?'
        ]
    ],
    'max_tokens' => 1024,
    'system' => 'You are a helpful assistant.',
    'stream' => false,
    'stop_sequences' => [
        '<string>'
    ],
    'tools' => [
        [
                
        ]
    ],
    'tool_choice' => [
        
    ],
    'thinking' => [
        
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.linkmodel.ai/v1/messages"

	payload := strings.NewReader("{\n  \"model\": \"claude-fable-5\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello, who are you?\"\n    }\n  ],\n  \"max_tokens\": 1024,\n  \"system\": \"You are a helpful assistant.\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {}\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.linkmodel.ai/v1/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"claude-fable-5\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello, who are you?\"\n    }\n  ],\n  \"max_tokens\": 1024,\n  \"system\": \"You are a helpful assistant.\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {}\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.linkmodel.ai/v1/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"claude-fable-5\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello, who are you?\"\n    }\n  ],\n  \"max_tokens\": 1024,\n  \"system\": \"You are a helpful assistant.\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {}\n}"

response = http.request(request)
puts response.read_body

{
  "id": "msg_abc123",
  "type": "message",
  "role": "assistant",
  "model": "claude-opus-4-7",
  "content": [
    {
      "type": "text",
      "text": "I'm Claude, an AI assistant made by Anthropic."
    }
  ],
  "stop_reason": "end_turn",
  "stop_sequence": "<string>",
  "usage": {
    "input_tokens": 12,
    "output_tokens": 18
  }
}

Authorizations

Authorization

string

header

required

Bearer authentication header of the form Bearer <token>, where <token> is your auth token.

Body

application/json

model

string

required

ID of the chat model to use. See Models for the current model list, pricing, and endpoint support.

Example:

"claude-fable-5"

messages

object[]

required

Input messages. Alternating user / assistant turns.

Show child attributes

max_tokens

integer

required

The maximum number of tokens to generate before stopping. Required.

Example:

1024

system

string

A system prompt providing context and instructions, set at the top level.

Example:

"You are a helpful assistant."

stream

boolean

default:false

If true, the response is streamed as Server-Sent Events.

stop_sequences

string[]

Custom text sequences that will cause the model to stop generating. The generated text will not contain the stop sequence.

tools

object[]

Optional Anthropic-compatible tool definitions. Support can vary by selected model and provider.

tool_choice

Controls tool use. Support can vary by selected model and provider.

thinking

object

Optional thinking/reasoning controls for models that support them. Support can vary by selected model and provider.

Response

Message result. When stream is true, the body is an SSE stream instead.

string

Example:

"msg_abc123"

type

string

Example:

"message"

role

string

Example:

"assistant"

model

string

Example:

"claude-opus-4-7"

content

object[]

Show child attributes

stop_reason

enum<string>

Available options:

end_turn,

max_tokens,

stop_sequence

Example:

"end_turn"

stop_sequence

string | null

usage

object

Show child attributes

Anthropic Messages

curl --request POST \
  --url https://api.linkmodel.ai/v1/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "claude-fable-5",
  "messages": [
    {
      "role": "user",
      "content": "Hello, who are you?"
    }
  ],
  "max_tokens": 1024,
  "system": "You are a helpful assistant.",
  "stream": false,
  "stop_sequences": [
    "<string>"
  ],
  "tools": [
    {}
  ],
  "tool_choice": {},
  "thinking": {}
}
'

import requests

url = "https://api.linkmodel.ai/v1/messages"

payload = {
    "model": "claude-fable-5",
    "messages": [
        {
            "role": "user",
            "content": "Hello, who are you?"
        }
    ],
    "max_tokens": 1024,
    "system": "You are a helpful assistant.",
    "stream": False,
    "stop_sequences": ["<string>"],
    "tools": [{}],
    "tool_choice": {},
    "thinking": {}
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    model: 'claude-fable-5',
    messages: [{role: 'user', content: 'Hello, who are you?'}],
    max_tokens: 1024,
    system: 'You are a helpful assistant.',
    stream: false,
    stop_sequences: ['<string>'],
    tools: [{}],
    tool_choice: {},
    thinking: {}
  })
};

fetch('https://api.linkmodel.ai/v1/messages', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.linkmodel.ai/v1/messages",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'model' => 'claude-fable-5',
    'messages' => [
        [
                'role' => 'user',
                'content' => 'Hello, who are you?'
        ]
    ],
    'max_tokens' => 1024,
    'system' => 'You are a helpful assistant.',
    'stream' => false,
    'stop_sequences' => [
        '<string>'
    ],
    'tools' => [
        [
                
        ]
    ],
    'tool_choice' => [
        
    ],
    'thinking' => [
        
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.linkmodel.ai/v1/messages"

	payload := strings.NewReader("{\n  \"model\": \"claude-fable-5\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello, who are you?\"\n    }\n  ],\n  \"max_tokens\": 1024,\n  \"system\": \"You are a helpful assistant.\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {}\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://api.linkmodel.ai/v1/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"claude-fable-5\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello, who are you?\"\n    }\n  ],\n  \"max_tokens\": 1024,\n  \"system\": \"You are a helpful assistant.\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {}\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.linkmodel.ai/v1/messages")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"model\": \"claude-fable-5\",\n  \"messages\": [\n    {\n      \"role\": \"user\",\n      \"content\": \"Hello, who are you?\"\n    }\n  ],\n  \"max_tokens\": 1024,\n  \"system\": \"You are a helpful assistant.\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {}\n}"

response = http.request(request)
puts response.read_body

{
  "id": "msg_abc123",
  "type": "message",
  "role": "assistant",
  "model": "claude-opus-4-7",
  "content": [
    {
      "type": "text",
      "text": "I'm Claude, an AI assistant made by Anthropic."
    }
  ],
  "stop_reason": "end_turn",
  "stop_sequence": "<string>",
  "usage": {
    "input_tokens": 12,
    "output_tokens": 18
  }
}

Models

Image Generation

Video Generation

Chat

Credits

API Keys

Files API

Audio Generation

API essentials

Anthropic Messages

Authorizations

Body

Response