Docs API Reference SDK Reference Agentic Usage AI Skills

Messages (Anthropic)

Create a message

Requests a model response using Anthropic's native /v1/messages shape; BazaarLink routes it to any supported model, not just Anthropic's own. Point the official Anthropic SDK's base_url at BazaarLink and existing code works unchanged. Accepts either Authorization: Bearer or the Anthropic SDK's conventional x-api-key header. If the resolved model isn't native Anthropic, BazaarLink transparently translates the request/response, preserving tool_use blocks and stop_reason semantics where possible.

POST/api/v1/messages

Authorizations

Authorizationrequired

string · header

API key as bearer token in the Authorization header.

Body

modelrequired

string

The model to use, provider-qualified, e.g. "anthropic/claude-sonnet-4.6".

minLength: 1

Example: "anthropic/claude-sonnet-4.6"

messagesrequired

Message[]

Array of conversation messages, at least one. Each has a role (user/assistant) and content (a string, or an array of content blocks such as text/image/tool_use/tool_result).

minLength: 1

max_tokensrequired

integer

Maximum number of tokens the response may generate. Unlike the OpenAI-compatible endpoints, this field is required in the Anthropic shape.

positive integer

Example: 1024

system

string | ContentBlock[]

System prompt — a separate top-level field, not a message inside the messages array (one of the main shape differences from the OpenAI format).

stream

boolean

true streams the response as SSE (message_start / content_block_delta / message_delta / message_stop events); omitted or false returns a single JSON response.

temperature

number

Sampling temperature — higher is more random, lower is more deterministic. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

0–1

top_p

number

Nucleus sampling threshold. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

0–1

top_k

integer

Limits sampling to the K highest-probability tokens. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

stop_sequences

string[]

Array of strings where generation stops. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

tools

Tool[]

List of tool definitions the model may call, Anthropic-shaped (name, description, input_schema). Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

tool_choice

object

Controls whether/how the model is forced to call a tool, e.g. {type:"auto"}, {type:"any"}, {type:"tool", name:"..."}. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

thinking

object

Extended-thinking control object, e.g. {type:"enabled", budget_tokens:2048}. Only meaningful on reasoning models. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

metadata

object

Request metadata, e.g. {user_id:"..."}. Used for monitoring and abuse detection; has no effect on billing. Not validated by BazaarLink — forwarded as-is to the upstream. If the resolved model isn't native Anthropic, how this field is handled depends on BazaarLink's translation layer.

POST /api/v1/messages

1
2
3
4
5
6
7
8
curl https://bazaarlink.ai/api/v1/messages \
  -H "Authorization: Bearer $BAZAARLINK_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-sonnet-4.6",
    "max_tokens": 1024,
    "messages": [{"role": "user", "content": "Hello"}]
  }'

Response examples

Success. By default (or stream: false) returns the Anthropic-native Message object below; with stream: true, returns an SSE event stream instead (message_start / content_block_delta / message_delta / message_stop — see the deep guide for the protocol). model always echoes the name you requested (never the actually-resolved upstream model). usage keeps the native Anthropic fields (input_tokens, output_tokens, cache_creation_input_tokens, cache_read_input_tokens) plus cost/bz_cost — BazaarLink's own settled amount, never a value relayed from upstream.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
{
  "id": "msg_01XFDUDYJgAACzvnptvVoYEL",
  "type": "message",
  "role": "assistant",
  "model": "anthropic/claude-sonnet-4.6",
  "content": [
    {
      "type": "text",
      "text": "Hello! How can I help you today?"
    }
  ],
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "usage": {
    "input_tokens": 10,
    "output_tokens": 12,
    "cache_creation_input_tokens": 0,
    "cache_read_input_tokens": 0,
    "cost": 0.000186,
    "bz_cost": 0.000186
  }
}