Anthropic Messages API Reference

POST

direct

anthropic

messages

Anthropic Messages

curl --request POST \
  --url https://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "gloo-anthropic-claude-opus-5.5",
  "max_tokens": 2,
  "messages": [
    {
      "content": "<string>"
    }
  ],
  "system": "<string>",
  "stream": false,
  "stop_sequences": [
    "<string>"
  ],
  "temperature": 123,
  "top_p": 123,
  "top_k": 123,
  "tools": [
    {}
  ],
  "tool_choice": {},
  "thinking": {},
  "output_config": {},
  "cache_control": {},
  "context_management": {},
  "metadata": {
    "user_id": "<string>"
  }
}
'

import requests

url = "https://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages"

payload = {
    "model": "gloo-anthropic-claude-opus-5.5",
    "max_tokens": 2,
    "messages": [{ "content": "<string>" }],
    "system": "<string>",
    "stream": False,
    "stop_sequences": ["<string>"],
    "temperature": 123,
    "top_p": 123,
    "top_k": 123,
    "tools": [{}],
    "tool_choice": {},
    "thinking": {},
    "output_config": {},
    "cache_control": {},
    "context_management": {},
    "metadata": { "user_id": "<string>" }
}
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: 'gloo-anthropic-claude-opus-5.5',
    max_tokens: 2,
    messages: [{content: '<string>'}],
    system: '<string>',
    stream: false,
    stop_sequences: ['<string>'],
    temperature: 123,
    top_p: 123,
    top_k: 123,
    tools: [{}],
    tool_choice: {},
    thinking: {},
    output_config: {},
    cache_control: {},
    context_management: {},
    metadata: {user_id: '<string>'}
  })
};

fetch('https://platform.ai.gloo.com/ai/v2/direct/anthropic/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://platform.ai.gloo.com/ai/v2/direct/anthropic/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' => 'gloo-anthropic-claude-opus-5.5',
    'max_tokens' => 2,
    'messages' => [
        [
                'content' => '<string>'
        ]
    ],
    'system' => '<string>',
    'stream' => false,
    'stop_sequences' => [
        '<string>'
    ],
    'temperature' => 123,
    'top_p' => 123,
    'top_k' => 123,
    'tools' => [
        [
                
        ]
    ],
    'tool_choice' => [
        
    ],
    'thinking' => [
        
    ],
    'output_config' => [
        
    ],
    'cache_control' => [
        
    ],
    'context_management' => [
        
    ],
    'metadata' => [
        'user_id' => '<string>'
    ]
  ]),
  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://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages"

	payload := strings.NewReader("{\n  \"model\": \"gloo-anthropic-claude-opus-5.5\",\n  \"max_tokens\": 2,\n  \"messages\": [\n    {\n      \"content\": \"<string>\"\n    }\n  ],\n  \"system\": \"<string>\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"temperature\": 123,\n  \"top_p\": 123,\n  \"top_k\": 123,\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {},\n  \"output_config\": {},\n  \"cache_control\": {},\n  \"context_management\": {},\n  \"metadata\": {\n    \"user_id\": \"<string>\"\n  }\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://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"gloo-anthropic-claude-opus-5.5\",\n  \"max_tokens\": 2,\n  \"messages\": [\n    {\n      \"content\": \"<string>\"\n    }\n  ],\n  \"system\": \"<string>\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"temperature\": 123,\n  \"top_p\": 123,\n  \"top_k\": 123,\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {},\n  \"output_config\": {},\n  \"cache_control\": {},\n  \"context_management\": {},\n  \"metadata\": {\n    \"user_id\": \"<string>\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://platform.ai.gloo.com/ai/v2/direct/anthropic/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\": \"gloo-anthropic-claude-opus-5.5\",\n  \"max_tokens\": 2,\n  \"messages\": [\n    {\n      \"content\": \"<string>\"\n    }\n  ],\n  \"system\": \"<string>\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"temperature\": 123,\n  \"top_p\": 123,\n  \"top_k\": 123,\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {},\n  \"output_config\": {},\n  \"cache_control\": {},\n  \"context_management\": {},\n  \"metadata\": {\n    \"user_id\": \"<string>\"\n  }\n}"

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

{
  "id": "<string>",
  "type": "message",
  "role": "assistant",
  "model": "<string>",
  "content": [
    {}
  ],
  "stop_reason": "<string>",
  "stop_sequence": "<string>",
  "usage": {
    "input_tokens": 123,
    "output_tokens": 123,
    "cache_creation_input_tokens": 123,
    "cache_read_input_tokens": 123
  }
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "tools.0.type: \"web_fetch_20250910\" is not supported on this endpoint.",
    "details": {
      "code": "tool_not_supported",
      "retryable": false
    }
  },
  "request_id": "req_..."
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "overloaded_error",
    "message": "The model is temporarily unavailable. Retry shortly.",
    "details": {
      "code": "upstream_capacity",
      "retryable": true
    }
  },
  "request_id": "req_..."
}

Guide: Anthropic Messages

SDK setup, streaming, thinking, tools, supported betas, limits and errors.

Authorizations

Authorization

string

header

default:<api-key>

required

Bearer authentication header of the form Bearer <api-key>, where <api-key> is your API key.

Headers

anthropic-version

enum<string>

Optional. If sent, must be 2023-06-01.

Available options:

2023-06-01

anthropic-beta

string

Comma-separated beta features. Supported: context-management-2025-06-27, thinking-display-updates-2026-08-18, interleaved-thinking-2025-05-14, fine-grained-tool-streaming-2025-05-14. Any other value is dropped and named in x-gloo-ignored-betas.

Body

application/json

An Anthropic Messages request. Fields are as defined by Anthropic's Messages API. Any other top-level field is dropped and named in x-gloo-ignored-params.

model

string

required

A Claude model: a Gloo model ID such as gloo-anthropic-claude-opus-5.5, or Anthropic's ID such as claude-opus-5-5.

Example:

"gloo-anthropic-claude-opus-5.5"

max_tokens

integer

required

Maximum output tokens, including thinking. Above the model's output limit it is lowered to that limit. Above 21,333 requires stream: true.

Required range: x >= 1

messages

object[]

required

The conversation. Roles are user and assistant. Content is a string or an array of blocks: text, image (base64 or URL source), document (base64, text, content or URL source), search_result, tool_use, tool_result, thinking, redacted_thinking, and server_tool_use / web_search_tool_result when the web search tool is in tools. thinking and redacted_thinking blocks are accepted but not passed to the model; the x-gloo-ignored-params header lists messages.thinking when any were sent.

Minimum array length: 1

Show child attributes

system

System prompt: a string or an array of text blocks.

stream

boolean

default:false

Stream the response as Server-Sent Events.

stop_sequences

string[]

temperature

number

top_p

number

top_k

integer

tools

object[]

Your own tools, plus the Anthropic-defined web search (web_search_*), bash (bash_*) and text editor (text_editor_*) tools. Other tool types return 400.

tool_choice

object

thinking

object

Thinking configuration, sent as written, for example {"type": "adaptive", "display": "summarized"}.

output_config

object

Output configuration, sent as written, for example {"effort": "high"}.

cache_control

object

Automatic prompt caching, for example {"type": "ephemeral"}.

context_management

object

Context editing. Requires the context-management-2025-06-27 beta; otherwise dropped.

metadata

object

Only user_id is used, and it is not passed to the model provider as sent.

Show child attributes

Response

The model's message. With stream: true, a Server-Sent Events stream of Anthropic's Messages events (message_start, content_block_start, content_block_delta, content_block_stop, message_delta, message_stop, ping). A failure after the stream starts ends it with an error event.

An Anthropic message object. model is the model ID you sent.

string

type

enum<string>

Available options:

message

role

enum<string>

Available options:

assistant

model

string

content

object[]

stop_reason

string | null

stop_sequence

string | null

usage

object

Show child attributes

⌘I

Anthropic Messages

curl --request POST \
  --url https://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "model": "gloo-anthropic-claude-opus-5.5",
  "max_tokens": 2,
  "messages": [
    {
      "content": "<string>"
    }
  ],
  "system": "<string>",
  "stream": false,
  "stop_sequences": [
    "<string>"
  ],
  "temperature": 123,
  "top_p": 123,
  "top_k": 123,
  "tools": [
    {}
  ],
  "tool_choice": {},
  "thinking": {},
  "output_config": {},
  "cache_control": {},
  "context_management": {},
  "metadata": {
    "user_id": "<string>"
  }
}
'

import requests

url = "https://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages"

payload = {
    "model": "gloo-anthropic-claude-opus-5.5",
    "max_tokens": 2,
    "messages": [{ "content": "<string>" }],
    "system": "<string>",
    "stream": False,
    "stop_sequences": ["<string>"],
    "temperature": 123,
    "top_p": 123,
    "top_k": 123,
    "tools": [{}],
    "tool_choice": {},
    "thinking": {},
    "output_config": {},
    "cache_control": {},
    "context_management": {},
    "metadata": { "user_id": "<string>" }
}
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: 'gloo-anthropic-claude-opus-5.5',
    max_tokens: 2,
    messages: [{content: '<string>'}],
    system: '<string>',
    stream: false,
    stop_sequences: ['<string>'],
    temperature: 123,
    top_p: 123,
    top_k: 123,
    tools: [{}],
    tool_choice: {},
    thinking: {},
    output_config: {},
    cache_control: {},
    context_management: {},
    metadata: {user_id: '<string>'}
  })
};

fetch('https://platform.ai.gloo.com/ai/v2/direct/anthropic/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://platform.ai.gloo.com/ai/v2/direct/anthropic/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' => 'gloo-anthropic-claude-opus-5.5',
    'max_tokens' => 2,
    'messages' => [
        [
                'content' => '<string>'
        ]
    ],
    'system' => '<string>',
    'stream' => false,
    'stop_sequences' => [
        '<string>'
    ],
    'temperature' => 123,
    'top_p' => 123,
    'top_k' => 123,
    'tools' => [
        [
                
        ]
    ],
    'tool_choice' => [
        
    ],
    'thinking' => [
        
    ],
    'output_config' => [
        
    ],
    'cache_control' => [
        
    ],
    'context_management' => [
        
    ],
    'metadata' => [
        'user_id' => '<string>'
    ]
  ]),
  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://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages"

	payload := strings.NewReader("{\n  \"model\": \"gloo-anthropic-claude-opus-5.5\",\n  \"max_tokens\": 2,\n  \"messages\": [\n    {\n      \"content\": \"<string>\"\n    }\n  ],\n  \"system\": \"<string>\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"temperature\": 123,\n  \"top_p\": 123,\n  \"top_k\": 123,\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {},\n  \"output_config\": {},\n  \"cache_control\": {},\n  \"context_management\": {},\n  \"metadata\": {\n    \"user_id\": \"<string>\"\n  }\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://platform.ai.gloo.com/ai/v2/direct/anthropic/v1/messages")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"model\": \"gloo-anthropic-claude-opus-5.5\",\n  \"max_tokens\": 2,\n  \"messages\": [\n    {\n      \"content\": \"<string>\"\n    }\n  ],\n  \"system\": \"<string>\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"temperature\": 123,\n  \"top_p\": 123,\n  \"top_k\": 123,\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {},\n  \"output_config\": {},\n  \"cache_control\": {},\n  \"context_management\": {},\n  \"metadata\": {\n    \"user_id\": \"<string>\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://platform.ai.gloo.com/ai/v2/direct/anthropic/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\": \"gloo-anthropic-claude-opus-5.5\",\n  \"max_tokens\": 2,\n  \"messages\": [\n    {\n      \"content\": \"<string>\"\n    }\n  ],\n  \"system\": \"<string>\",\n  \"stream\": false,\n  \"stop_sequences\": [\n    \"<string>\"\n  ],\n  \"temperature\": 123,\n  \"top_p\": 123,\n  \"top_k\": 123,\n  \"tools\": [\n    {}\n  ],\n  \"tool_choice\": {},\n  \"thinking\": {},\n  \"output_config\": {},\n  \"cache_control\": {},\n  \"context_management\": {},\n  \"metadata\": {\n    \"user_id\": \"<string>\"\n  }\n}"

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

{
  "id": "<string>",
  "type": "message",
  "role": "assistant",
  "model": "<string>",
  "content": [
    {}
  ],
  "stop_reason": "<string>",
  "stop_sequence": "<string>",
  "usage": {
    "input_tokens": 123,
    "output_tokens": 123,
    "cache_creation_input_tokens": 123,
    "cache_read_input_tokens": 123
  }
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "tools.0.type: \"web_fetch_20250910\" is not supported on this endpoint.",
    "details": {
      "code": "tool_not_supported",
      "retryable": false
    }
  },
  "request_id": "req_..."
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "<string>",
    "details": {
      "code": "<string>",
      "developer_message": "<string>",
      "retryable": true
    }
  },
  "request_id": "<string>"
}

{
  "type": "error",
  "error": {
    "type": "overloaded_error",
    "message": "The model is temporarily unavailable. Retry shortly.",
    "details": {
      "code": "upstream_capacity",
      "retryable": true
    }
  },
  "request_id": "req_..."
}

General

Models

Responses & Completions

Embeddings

Content

Data Engine Content Controls

Legacy / Deprecated APIs

Anthropic Messages API Reference

Guide: Anthropic Messages

Authorizations

Headers

Body

Response