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Installation

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Overview

The @ai-billing/anthropic package provides middleware for tracking token usage and calculating costs when using Anthropic models with the Vercel AI SDK. It captures Anthropic-specific metrics, such as inputCacheReadTokens and inputCacheWriteTokens, ensuring that Prompt Caching costs are accurately reflected.

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Usage

To use the middleware, wrap your Anthropic model using wrapLanguageModel from the ai package and pass the createAnthropicMiddleware.
1

Initialize the Anthropic provider

First, set up the Anthropic provider using your API key.
2

Define model pricing

Set up a price resolver to define the costs for the models you’ll be using. For Anthropic, you can specify costs for both standard prompt/completion tokens and cached tokens (inputCacheReadTokens and inputCacheWriteTokens).
3

Create the billing middleware

Initialize the Anthropic billing middleware. You need to provide a destination (such as consoleDestination) where billing events will be sent, along with your priceResolver.
4

Wrap the model

Use wrapLanguageModel from the ai package to apply the billing middleware to your Anthropic model.
5

Use the wrapped model

Finally, use the wrapped model with AI SDK functions like generateText or streamText. The billing middleware will automatically track tokens, handle caching metrics, and calculate costs.