Anthropic SDK

The Anthropic SDK connects to Claude’s native Messages API. Set the base URL to https://gateway.toolken.ai (no /v1 suffix — the SDK appends /v1/messages itself) and add X-Toolken-Key as a default header.

The base URL for the Anthropic SDK is https://gateway.toolken.ai with no /v1 at the end. The SDK appends /v1/messages automatically. Adding /v1 yourself will cause routing errors.

Get your keys

You need two keys:

Key	Where to get it	Looks like
Toolken key	Dashboard, under API Keys	`tk_live_...`
Anthropic key	Your Anthropic account	`sk-ant-...`

Toolken forwards your Anthropic key verbatim and never stores it.

Configure the client

import anthropic

client = anthropic.Anthropic(
    base_url="https://gateway.toolken.ai",  # no /v1 -- SDK appends /v1/messages
    api_key="sk-ant-...",                   # your Anthropic key, forwarded untouched
    default_headers={
        "X-Toolken-Key": "tk_live_...",
        "X-Toolken-Metadata-Agent": "my-agent",  # tag this client's traffic
    },
)

message = client.messages.create(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Hello"}],
)
print(message.content[0].text)

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

const client = new Anthropic({
  baseURL: "https://gateway.toolken.ai",  // no /v1 -- SDK appends /v1/messages
  apiKey: process.env.ANTHROPIC_API_KEY,  // forwarded untouched
  defaultHeaders: {
    "X-Toolken-Key": "tk_live_...",
    "X-Toolken-Metadata-Agent": "my-agent",  // tag this client's traffic
  },
});

const message = await client.messages.create({
  model: "claude-3-5-sonnet-20241022",
  max_tokens: 1024,
  messages: [{ role: "user", content: "Hello" }],
});
console.log(message.content[0].text);

X-Toolken-Metadata-Agent takes any string. Use one value per agent or workflow you want to track separately in the dashboard. Any X-Toolken-Metadata-* header becomes a groupable dimension automatically.

Attribute by customer (optional)

Add X-Toolken-Metadata-Customer-Id to track spend per end-user or organization:

client = anthropic.Anthropic(
    base_url="https://gateway.toolken.ai",
    api_key="sk-ant-...",
    default_headers={
        "X-Toolken-Key": "tk_live_...",
        "X-Toolken-Metadata-Agent": "support-agent",
        "X-Toolken-Metadata-Customer-Id": "org_abc123",
    },
)

const client = new Anthropic({
  baseURL: "https://gateway.toolken.ai",
  apiKey: process.env.ANTHROPIC_API_KEY,
  defaultHeaders: {
    "X-Toolken-Key": "tk_live_...",
    "X-Toolken-Metadata-Agent": "support-agent",
    "X-Toolken-Metadata-Customer-Id": "org_abc123",
  },
});

See your cost

Within seconds your request appears in the dashboard, grouped by agent and customer. The response body is identical to calling Anthropic directly — Toolken is a transparent proxy.

Streaming

The Anthropic SDK’s streaming API works without any changes:

with client.messages.stream(
    model="claude-3-5-sonnet-20241022",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Count to five."}],
) as stream:
    for text in stream.text_stream:
        print(text, end="", flush=True)

const stream = await client.messages.create({
  model: "claude-3-5-sonnet-20241022",
  max_tokens: 1024,
  messages: [{ role: "user", content: "Count to five." }],
  stream: true,
});
for await (const event of stream) {
  if (
    event.type === "content_block_delta" &&
    event.delta.type === "text_delta"
  ) {
    process.stdout.write(event.delta.text);
  }
}

How the two keys travel

The Anthropic SDK injects your key as x-api-key. Toolken reads X-Toolken-Key separately and forwards x-api-key unchanged.

Header	Who reads it	What happens after
`X-Toolken-Key: tk_live_...`	Toolken gateway	Stripped before forwarding
`x-api-key: sk-ant-...`	Anthropic	Forwarded untouched
`X-Toolken-Metadata-Agent: ...`	Toolken gateway	Recorded as metadata key `agent`, then stripped
`X-Toolken-Metadata-Customer-Id: ...`	Toolken gateway	Recorded as metadata key `customer_id`, then stripped

Provider detection

Any request to /v1/messages routes to Anthropic automatically. A model name starting with claude- also triggers auto-detection. You do not need an X-Toolken-Provider header.

Custom Properties

All attribution headers and how metadata keys become dashboard dimensions.

OpenAI SDK

Use OpenAI and OpenAI-compatible models through Toolken.

Gemini SDK

Use Gemini models through Toolken via the OpenAI-compatible path.

Anthropic and Gemini

Provider routing details for Anthropic and Gemini.

Getting Started

Observability

Providers & Routing

Rate Limits

Integrations

Use cases

Streaming

How the two keys travel

Provider detection

Next

Custom Properties

OpenAI SDK

Gemini SDK

Anthropic and Gemini

​Streaming

​How the two keys travel

​Provider detection

​Next

Custom Properties

OpenAI SDK

Gemini SDK

Anthropic and Gemini

Streaming

How the two keys travel

Provider detection

Next