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Braintrust Exporter

Braintrust is an evaluation and monitoring platform that helps you measure and improve LLM application quality. The Braintrust exporter sends your traces to Braintrust, enabling systematic evaluation, scoring, and experimentation.

Installation​

npm install @mastra/braintrust@beta

Configuration​

Prerequisites​

  1. Braintrust Account: Sign up at braintrust.dev
  2. Project: Create or select a project for your traces
  3. API Key: Generate in Braintrust Settings → API Keys
  4. Environment Variables: Set your credentials:
.env
BRAINTRUST_API_KEY=sk-xxxxxxxxxxxxxxxx
BRAINTRUST_PROJECT_NAME=my-project  # Optional, defaults to 'mastra-tracing'

Basic Setup​

src/mastra/index.ts
import { Mastra } from "@mastra/core";
import { Observability } from "@mastra/observability";
import { BraintrustExporter } from "@mastra/braintrust";

export const mastra = new Mastra({
  observability: new Observability({
    configs: {
      braintrust: {
        serviceName: "my-service",
        exporters: [
          new BraintrustExporter({
            apiKey: process.env.BRAINTRUST_API_KEY,
            projectName: process.env.BRAINTRUST_PROJECT_NAME,
          }),
        ],
      },
    },
  }),
});

Complete Configuration​

new BraintrustExporter({
  // Required
  apiKey: process.env.BRAINTRUST_API_KEY!,

  // Optional settings
  projectName: "my-project", // Default: 'mastra-tracing'
  endpoint: "https://api.braintrust.dev", // Custom endpoint if needed
  logLevel: "info", // Diagnostic logging: debug | info | warn | error
});

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