Setup Install the Braintrust Genkit integration: ```bash theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}} go get github.com/braintrustdata/braintrust-sdk-go/trace/contrib/genkit ``` Manual instrumentation To trace Firebase Genkit calls, attach Braintrust’s middleware by passing `tracegenkit.NewMiddleware()` to `ai.WithMiddleware(...)` on each Genkit call you want to trace. ```go Go theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}} package main import ( "context" "fmt" "log" "os" "github.com/firebase/genkit/go/ai" "github.com/firebase/genkit/go/genkit" "github.com/firebase/genkit/go/plugins/googlegenai" "go.opentelemetry.io/otel" "go.opentelemetry.io/otel/sdk/trace" "github.com/braintrustdata/braintrust-sdk-go" tracegenkit "github.com/braintrustdata/braintrust-sdk-go/trace/contrib/genkit" ) func main() { tp := trace.NewTracerProvider() defer tp.Shutdown(context.Background()) otel.SetTracerProvider(tp) bt, err := braintrust.New(tp, braintrust.WithProject("my-genkit-project"), braintrust.WithAPIKey(os.Getenv("BRAINTRUST_API_KEY")), ) if err != nil { log.Fatal(err) } ctx := context.Background() g := genkit.Init(ctx, genkit.WithPlugins(&googlegenai.GoogleAI{ APIKey: os.Getenv("GOOGLE_API_KEY"), }), genkit.WithDefaultModel("googleai/gemini-2.5-flash"), ) tracer := otel.Tracer("genkit-example") ctx, span := tracer.Start(ctx, "genkit-call") defer span.End() mw := tracegenkit.NewMiddleware() resp, err := genkit.Generate(ctx, g, ai.WithPrompt("What is the capital of France?"), ai.WithMiddleware(mw), ) if err != nil { log.Fatal(err) } fmt.Printf("Response: %s\n", resp.Text()) fmt.Printf("View trace: %s\n", bt.Permalink(span)) } ``` Streaming To trace streaming responses from `genkit.GenerateStream`, pass the same middleware to that call: ```go #skip-compile theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}} stream, err := genkit.GenerateStream(ctx, g, ai.WithPrompt("Tell me a story"), ai.WithMiddleware(mw), ) if err != nil { log.Fatal(err) } _ = stream ``` Tracing embeddings Genkit does not route embedding calls through its model middleware, so `tracegenkit.NewMiddleware()` does not capture them. To trace embeddings, wrap each embedder with `tracegenkit.WrapEmbedder`. The wrapped value implements `ai.Embedder` and can be used as a drop-in replacement with `ai.WithEmbedder(...)`. ```go #skip-compile theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}} import ( "github.com/firebase/genkit/go/ai" "github.com/firebase/genkit/go/genkit" tracegenkit "github.com/braintrustdata/braintrust-sdk-go/trace/contrib/genkit" ) embedder := tracegenkit.WrapEmbedder( genkit.LookupEmbedder(g, "googleai/gemini-embedding-001"), tracegenkit.WithEmbedderModel("gemini-embedding-001"), tracegenkit.WithEmbedderProvider("googleai"), ) resp, err := genkit.Embed(ctx, g, ai.WithEmbedder(embedder), ai.WithTextDocs("text 1", "text 2"), ) ``` What Braintrust traces Braintrust captures: * `genkit.Generate`, `genkit.GenerateText`, and `genkit.GenerateStream` inputs, outputs, and finish reasons * Streaming responses, with `time_to_first_token` captured on the first chunk * Token usage, including cached input tokens and reasoning (thoughts) tokens * Tool calls and tool results * Model configuration (model, temperature, top\_p, max output tokens, etc.) and response metadata (latency, provider, request id) * `genkit.Embed` inputs, embedding count, and dimensions when wrapped with `WrapEmbedder` Tracing resources * [Firebase Genkit documentation](https://firebase.google.com/docs/genkit) * [Go SDK example](https://github.com/braintrustdata/braintrust-sdk-go/tree/main/examples/genkit)