Mastra

LangWatch traces agents built with Mastra, the TypeScript agent framework.

Quick setup? Instead of following these steps manually, copy a prompt into your coding agent and it will set this up for you automatically.

LangWatch integrates with Mastra through OpenTelemetry to capture traces from your Mastra agents automatically.

Installation

npm

npm i langwatch @mastra/core @ai-sdk/openai @mastra/observability @mastra/otel-exporter @mastra/libsql

Usage

Configure your Mastra instance with OpenTelemetry exporter pointing to LangWatch:

import { Agent } from "@mastra/core/agent";
import { Mastra } from "@mastra/core";
import { openai } from "@ai-sdk/openai";
import { Observability } from "@mastra/observability";
import { OtelExporter } from "@mastra/otel-exporter";
import { LibSQLStore } from "@mastra/libsql";

export const mastra = new Mastra({
  agents: {
    assistant: new Agent({
      name: "assistant",
      instructions: "You are a helpful assistant.",
      model: openai("gpt-5-mini"),
    }),
  },
  storage: new LibSQLStore({ id: "mastra-storage", url: "file:./mastra.db" }),
  observability: new Observability({
    configs: {
      langwatch: {
        serviceName: "<project_name>",
        exporters: [
          new OtelExporter({
            provider: {
              custom: {
                endpoint: "https://app.langwatch.ai/api/otel/v1/traces",
                headers: { Authorization: `Bearer ${process.env.LANGWATCH_API_KEY}` },
              },
            },
          }),
        ],
      },
    },
  }),
});

Mastra automatically sends traces to LangWatch through the OpenTelemetry exporter. All agent interactions, tool calls, and workflow executions will be captured.

Related

• Capturing RAG - Learn how to capture RAG data from retrievers and tools
• Capturing Metadata and Attributes - Add custom metadata and attributes to your traces and spans
• Capturing Evaluations & Guardrails - Log evaluations and implement guardrails in your Mastra applications