Module @langfuse/vercel-ai-sdk

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@langfuse/vercel-ai-sdk

This package provides a Langfuse-owned telemetry integration for AI SDK v7 (ai@7) using the new callback-based telemetry system.

It delegates AI SDK-compatible OpenTelemetry span creation to Vercel's @ai-sdk/otel package so it works with the existing Langfuse OTEL ingestion pipeline, and it adds Langfuse-specific observation attributes for prompt linking and observation metadata.

Trace-level attributes such as user ID, session ID, tags, trace name, and trace metadata should be set with propagateAttributes from @langfuse/tracing.

Usage

import { generateText, registerTelemetry } from "ai";
import { propagateAttributes } from "@langfuse/tracing";
import { LangfuseVercelAiSdkIntegration } from "@langfuse/vercel-ai-sdk";

registerTelemetry(new LangfuseVercelAiSdkIntegration());

await propagateAttributes(
  {
    userId: "user-123",
    sessionId: "session-456",
    tags: ["production", "chat"],
    metadata: {
      feature: "assistant",
    },
  },
  () =>
    generateText({
      model,
      prompt: "Explain RAG in one paragraph",
      runtimeContext: {
        langfuse: {
          metadata: {
            route: "support-chat",
          },
          prompt: {
            name: "assistant/default",
            version: 3,
            isFallback: false,
          },
        },
      },
      telemetry: {
        functionId: "chat-assistant",
      },
    }),
);

You can also pass the integration on a single call:

import { generateText } from "ai";
import { LangfuseVercelAiSdkIntegration } from "@langfuse/vercel-ai-sdk";

await generateText({
  model,
  prompt: "Summarize this article",
  telemetry: {
    functionId: "article-summary",
    integrations: new LangfuseVercelAiSdkIntegration({
      langfuse: {
        metadata: {
          feature: "article-summary",
        },
      },
    }),
  },
});

Packages

Package	Description	Environments
@langfuse/client	Langfuse API client for universal JavaScript environments	Universal JS
@langfuse/tracing	Langfuse instrumentation methods based on OpenTelemetry	Node.js 20+
@langfuse/otel	Langfuse OpenTelemetry export helpers	Node.js 20+
@langfuse/openai	Langfuse integration for OpenAI SDK	Universal JS
@langfuse/langchain	Langfuse integration for LangChain	Universal JS
@langfuse/vercel-ai-sdk	Langfuse integration for AI SDK v7	Universal JS