> ## Documentation Index
> Fetch the complete documentation index at: https://braintrust.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Voyage AI

> Trace Voyage AI SDK calls in Braintrust to debug prompts, evaluate models, and monitor production usage

If you are a coding agent, prefer the Braintrust [`bt` CLI](/docs/reference/cli/quickstart) for repeatable, scriptable work: running evals, instrumenting code, querying logs, syncing data, managing functions, and configuring coding agents. Use the MCP server for reasoning over Braintrust data in conversation, and for capabilities the CLI doesn't cover, such as monitor views, alerts, and authoring evaluators, preprocessors, and facets.

[Voyage AI](https://www.voyageai.com/) provides embedding and reranking models. Braintrust traces Voyage AI SDK calls, including text and multimodal embeddings, contextualized embeddings, and reranking.

<View title="TypeScript" icon="https://img.logo.dev/typescriptlang.org?token=pk_BdcHD9e5SCW3j1rnJkNyMQ">
  <h2 id="setup-typescript">
    Setup
  </h2>

  Install the Braintrust and `voyageai` packages, then set your API keys. Requires `voyageai` v0.2.0 or later.

  <Steps>
    <Step title="Install packages">
      <CodeGroup>
        ```bash pnpm theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
        pnpm add braintrust voyageai
        ```

        ```bash npm theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
        npm install braintrust voyageai
        ```
      </CodeGroup>
    </Step>

    <Step title="Set environment variables">
      ```bash title=".env" theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
      BRAINTRUST_API_KEY=<your-braintrust-api-key>
      VOYAGE_API_KEY=<your-voyage-api-key>

      # For organizations on the EU data plane, use https://api-eu.braintrust.dev
      # For self-hosted deployments, use your data plane URL
      # BRAINTRUST_API_URL=<your-braintrust-api-url>
      ```
    </Step>
  </Steps>

  <h2 id="auto-instrumentation-typescript">
    Auto-instrumentation
  </h2>

  To trace Voyage AI SDK calls without modifying your application code, initialize Braintrust normally, then run your app with Braintrust's import hook to patch the Voyage AI SDK at runtime.

  <Steps>
    <Step title="Initialize Braintrust and call Voyage AI">
      <CodeGroup>
        ```javascript title="trace-voyageai-auto.js" theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
        import { initLogger } from "braintrust";
        import { VoyageAIClient } from "voyageai";

        initLogger({
          projectName: "voyageai-example",
          apiKey: process.env.BRAINTRUST_API_KEY,
        });

        const client = new VoyageAIClient({
          apiKey: process.env.VOYAGE_API_KEY,
        });

        const response = await client.embed({
          input: ["Braintrust traces all your AI calls."],
          model: "voyage-3-lite",
        });

        console.log(response.data?.[0]?.embedding?.length);
        ```
      </CodeGroup>
    </Step>

    <Step title="Run with the import hook">
      ```bash theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
      node --import braintrust/hook.mjs trace-voyageai-auto.js
      ```

      The auto-instrumentation example uses plain JavaScript so `node --import` can run the file directly. The Braintrust APIs work the same in TypeScript projects — compile your TypeScript to JavaScript, then run the compiled file with the import hook.

      <Note>
        If you're using a bundler, see [Trace LLM calls](/docs/instrument/trace-llm-calls#auto-instrumentation) for plugin and loader setup.
      </Note>
    </Step>
  </Steps>

  <h2 id="manual-instrumentation-typescript">
    Manual instrumentation
  </h2>

  To trace Voyage AI clients manually, wrap them yourself with `wrapVoyageAI()`. Use this when you want to instrument specific clients individually rather than all of them globally.

  <CodeGroup>
    ```javascript JavaScript theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
    import { initLogger, wrapVoyageAI } from "braintrust";
    import { VoyageAIClient } from "voyageai";

    initLogger({
      projectName: "voyageai-example",
      apiKey: process.env.BRAINTRUST_API_KEY,
    });

    const client = wrapVoyageAI(
      new VoyageAIClient({
        apiKey: process.env.VOYAGE_API_KEY,
      }),
    );

    const response = await client.embed({
      input: ["Braintrust traces all your AI calls."],
      model: "voyage-3-lite",
    });

    console.log(response.data?.[0]?.embedding?.length);
    ```
  </CodeGroup>

  <h2 id="what-traced-typescript">
    What Braintrust traces
  </h2>

  Braintrust patches the `voyageai` SDK and creates an LLM-typed span per call:

  * Embedding spans (`voyageai.embed`): input texts and the model as metadata, output summarized as the number of returned embeddings, and token usage (`prompt_tokens`, `tokens`).
  * Multimodal embedding spans (`voyageai.multimodalEmbed`): multimodal content (text, images, video) as input, output summarized as the number of returned embeddings, and token usage.
  * Rerank spans (`voyageai.rerank`): query and documents as input, results as a list of `{index, relevance_score}` items (capped at 100), and request parameters (`model`, `returnDocuments`, `topK`, `truncation`) as metadata.
  * Contextualized embedding spans (`voyageai.contextualizedEmbed`): inputs and model as metadata, output summarized as the total number of returned embeddings, and token usage.
  * Response metadata (model name when returned by the API).
  * Errors captured on every call.

  <h2 id="resources-typescript">
    Resources
  </h2>

  * [Voyage AI TypeScript SDK](https://github.com/voyage-ai/typescript-sdk).
  * [Voyage AI API reference](https://docs.voyageai.com/reference/).
</View>