@usagetap/observer

A tiny, fail-open wrapper for UsageTap's 30-day usage and cost analysis trial. It sends only provider/model metadata, token counts, timing, status, and optional feature tags. It never sends prompts, model responses, or provider credentials.

import OpenAI from "openai";
import { observeOpenAI } from "@usagetap/observer";

const openai = observeOpenAI(new OpenAI(), {
  feature: "support-assistant",
});

const response = await openai.chat.completions.create({
  model: "gpt-4.1-mini",
  messages,
});

Anthropic uses the same options:

import Anthropic from "@anthropic-ai/sdk";
import { observeAnthropic } from "@usagetap/observer";

const anthropic = observeAnthropic(new Anthropic());

Set USAGETAP_API_KEY as a server-side environment variable. Trial keys infer their private workspace automatically. Full accounts can optionally pass a customerId when one key reports usage for multiple end customers.

The observer supports OpenAI-compatible chat completions, Responses API calls, and Anthropic Messages calls. Streams pass through while the observer reads only metadata-bearing usage events; it never buffers or sends content chunks.

UsageTap network requests are kept off the provider response path. In ordinary long-running Node processes, queued metadata is delivered in the background. In short-lived jobs or serverless handlers, flush before the process exits:

await openai.flushUsageTap();

Move to @usagetap/sdk when you deliberately need customer or user attribution, limits, gateway routing, sampling, managed compression, alerts, or forecasts.