Messages (Anthropic)

Use it when

• Your application already targets the Anthropic Messages API.
• You use Claude Code, Cline or another Anthropic-compatible agent.
• You need Anthropic-style system, tools, tool_choice or streaming events.

Code examples

curl https://api.prismaticapi.com/v1/messages \
  -H "x-api-key: $PRISMATIC_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-6",
    "max_tokens": 400,
    "messages": [
      { "role": "user", "content": "Draft a deployment checklist." }
    ]
  }'

import Anthropic from "@anthropic-ai/sdk";

const client = new Anthropic({
  apiKey: process.env.PRISMATIC_API_KEY,
  baseURL: "https://api.prismaticapi.com"
});

const message = await client.messages.create({
  model: "claude-sonnet-4-6",
  max_tokens: 400,
  messages: [{ role: "user", content: "Draft a deployment checklist." }]
});

Parameters

• model (string, required) — Public model ID returned by GET /v1/models.
• messages (array, required) — Array with role (user or assistant) and content.
• max_tokens (integer, required) — Maximum tokens to generate.
• system (string or array, optional) — System prompt as a string or text blocks.
• stream (boolean, optional) — Enables Anthropic-style SSE streaming.
• temperature (number, optional) — Sampling temperature.
• top_p (number, optional) — Nucleus sampling threshold.
• top_k (integer, optional) — Top-K sampling parameter.
• stop_sequences (array, optional) — Array of stop sequences.
• tools (array, optional) — Anthropic-format tool definitions.
• tool_choice (object, optional) — Tool choice strategy such as type=auto, type=any or a named tool choice.

Authentication

• Preferred Anthropic-style header: x-api-key: pa_YOUR_KEY.
• Also send anthropic-version: 2023-06-01 for Anthropic-compatible clients.
• Bearer authentication is also accepted for direct HTTP clients.

Notes

• Use /v1/messages/count_tokens to estimate input tokens before generation.
• Streaming PAYG settlement requires the client to consume the stream to completion.
• Vision and tools depend on the selected public model capabilities.