@tozil/anthropic

Tozil instrumentation for the Anthropic SDK.

Automatically tracks every messages.create() and messages.stream() call — model, tokens, latency — with zero code changes to your Anthropic usage.

Install

npm install @tozil/core @tozil/anthropic

Usage

import { init } from "@tozil/core";
import { anthropic } from "@tozil/anthropic";

init({
  apiKey: "tz_...",
  instrumentations: [anthropic()],
});

// Use Anthropic as normal — tracking is automatic
import Anthropic from "@anthropic-ai/sdk";
const client = new Anthropic();

const message = await client.messages.create({
  model: "claude-sonnet-4-20250514",
  max_tokens: 1024,
  messages: [{ role: "user", content: "Hello" }],
});

How it works

The plugin monkey-patches messages.create() and messages.stream() on the Anthropic SDK prototype. It captures:

• Model name
• Input/output token counts (from usage in the response)
• Latency in milliseconds
• User and endpoint context (if set via @tozil/core)

It does not capture prompts, completions, or any content.

Streaming support

Both messages.create({ stream: true }) and messages.stream() are fully supported. Token usage is captured from message_start and message_delta stream events.

License

MIT