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Documentation Index

Fetch the complete documentation index at: https://langwatch.ai/docs/llms.txt

Use this file to discover all available pages before exploring further.

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.

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Installation

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

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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.