Braintrust Exporter
Braintrust is an evaluation and monitoring platform that helps you measure and improve LLM application quality. The Braintrust exporter sends your AI traces to Braintrust, enabling systematic evaluation, scoring, and experimentation.
When to Use Braintrust
Braintrust excels at:
- Evaluation workflows - Systematic quality measurement
- Experiment tracking - Compare model versions and prompts
- Dataset management - Curate test cases and golden datasets
- Regression testing - Ensure improvements don’t break existing functionality
- Team collaboration - Share experiments and insights
Installation
npm install @mastra/braintrustConfiguration
Prerequisites
- Braintrust Account: Sign up at braintrust.devÂ
- Project: Create or select a project for your traces
- API Key: Generate in Braintrust Settings → API Keys
- 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 { BraintrustExporter } from "@mastra/braintrust";
export const mastra = new Mastra({
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
})