Claude Agent SDK (JS/TS)

Trace Anthropic's Claude Agent SDK in TypeScript with Muster via OpenInference instrumentation.

The Claude Agent SDK is Anthropic's open-source framework for building AI agents in TypeScript. Muster captures every agent step, tool call, and model completion through the OpenInference Claude Agent SDK instrumentation.

Setup

1. Install dependencies

npm install @anthropic-ai/claude-agent-sdk @arizeai/openinference-instrumentation-claude-agent-sdk @langfuse/otel @opentelemetry/sdk-node

2. Configure environment

process.env.ANTHROPIC_API_KEY = "sk-ant-...";

process.env.LANGFUSE_PUBLIC_KEY = "pk-lf-...";
process.env.LANGFUSE_SECRET_KEY = "sk-lf-...";
process.env.LANGFUSE_BASE_URL = "https://app.getmuster.io";

3. Initialize OpenTelemetry

import { NodeSDK } from "@opentelemetry/sdk-node";
import { LangfuseSpanProcessor, isDefaultExportSpan } from "@langfuse/otel";
import { ClaudeAgentSDKInstrumentation } from "@arizeai/openinference-instrumentation-claude-agent-sdk";
import * as ClaudeAgentSDKModule from "@anthropic-ai/claude-agent-sdk";

const ClaudeAgentSDK = { ...ClaudeAgentSDKModule };

const instrumentation = new ClaudeAgentSDKInstrumentation();
instrumentation.manuallyInstrument(ClaudeAgentSDK);

const sdk = new NodeSDK({
  spanProcessors: [
    new LangfuseSpanProcessor({
      shouldExportSpan: ({ otelSpan }) =>
        isDefaultExportSpan(otelSpan) ||
        otelSpan.instrumentationScope.name ===
          "@arizeai/openinference-instrumentation-claude-agent-sdk",
    }),
  ],
  instrumentations: [instrumentation],
});

sdk.start();

4. Run an agent

const { query } = ClaudeAgentSDK;

for await (const message of query({
  prompt: "What is the capital of France? Answer in a single sentence.",
  options: {
    model: "claude-sonnet-4-5",
  },
})) {
  if (message.type === "assistant") {
    console.log(message.message.content);
  }
}

await sdk.shutdown();

5. View the trace

Claude Agent SDK JS/TS trace in Muster