Anthropic SDK - Triw

Triw implements the Anthropic Messages API. Use the official anthropic SDK, or any client that targets /v1/messages.

Install

pip install anthropic

npm install @anthropic-ai/sdk

Configure

Setting	Official Anthropic	Triw
Base URL	`https://api.anthropic.com`	`https://router.triw.io`
Key	`sk-ant-...`	`sk-...` from Triw
Endpoint	`/v1/messages`	`/v1/messages` (same path)

Unlike the OpenAI SDK, the Anthropic SDK does not append /v1 for you — pass the host only.

import anthropic

client = anthropic.Anthropic(
    api_key="sk-...",                 # Triw key
    base_url="https://router.triw.io" # host only
)

msg = client.messages.create(
    model="claude-sonnet-4-5",
    max_tokens=512,
    messages=[{"role": "user", "content": "Explain TCP slow start in 3 bullets."}],
)
print(msg.content[0].text)

curl https://router.triw.io/v1/messages \
  -H "x-api-key: $TRIW_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-sonnet-4-5",
    "max_tokens": 256,
    "messages": [{"role": "user", "content": "ping"}]
  }'

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

const client = new Anthropic({
  apiKey: process.env.TRIW_API_KEY,
  baseURL: "https://router.triw.io",
});

const msg = await client.messages.create({
  model: "claude-sonnet-4-5",
  max_tokens: 512,
  messages: [{ role: "user", content: "ping" }],
});

Authentication details

x-api-key: sk-... is accepted on Anthropic routes.
Authorization: Bearer sk-... also works — useful when a tool only exposes one auth style.
Keep the anthropic-version header. Triw forwards it; the upstream channel decides whether it matters.

Token counting

curl https://router.triw.io/v1/messages/count_tokens \
  -H "x-api-key: $TRIW_API_KEY" \
  -H "anthropic-version: 2023-06-01" \
  -H "Content-Type: application/json" \
  -d '{"model":"claude-sonnet-4-5","messages":[{"role":"user","content":"hello"}]}'

Streaming and tools

stream: true works; events arrive in Anthropic’s SSE format (message_start, content_block_delta, message_stop). Tool use (tools, tool_choice) is passed through unchanged.

Using Claude models from an OpenAI-style client

You can also call Claude models through /v1/chat/completions, since Triw translates between formats. Pick one style per integration; mixing both in one codebase doubles the number of response parsers you maintain.