Lab: Send, Inspect, and Log Your First Model Request

import OpenAI from "openai";
import { appendFile } from "node:fs/promises";

const apiKey = process.env.OPENAI_API_KEY;
const model = process.env.OPENAI_MODEL;

if (!apiKey) throw new Error("OPENAI_API_KEY is missing from the environment");
if (!model) throw new Error("OPENAI_MODEL is missing from the environment");

const prompt = [
  "Classify this synthetic support message.",
  "Return two lines only: category and one-sentence reason.",
  "Message: My demo order arrived with the wrong colour.",
].join("\n");

if (prompt.length > 500) throw new Error("Prompt exceeds this lab's input cap");

const client = new OpenAI({ apiKey });
const startedAt = new Date();
const startMs = performance.now();

try {
  const response = await client.responses.create({
    model,
    input: prompt,
  });

  const elapsedMs = Math.round(performance.now() - startMs);
  const output = response.output_text?.trim() ?? "";
  if (!output) throw new Error("The response contained no output text");

  console.log(output);
  console.log({ responseId: response.id, model: response.model, elapsedMs });

  const logRecord = {
    timestamp: startedAt.toISOString(),
    task: "synthetic-support-classification",
    response_id: response.id,
    configured_model: model,
    returned_model: response.model ?? null,
    elapsed_ms: elapsedMs,
    usage: response.usage ?? null,
    output_review: {
      non_empty: output.length > 0,
      line_count: output.split(/\r?\n/).filter(Boolean).length,
    },
  };

  await appendFile("request-log.jsonl", `${JSON.stringify(logRecord)}\n`, "utf8");
} catch (error) {
  const safeError = {
    name: error?.name ?? "Error",
    status: error?.status ?? null,
    message: String(error?.message ?? "Unknown error").slice(0, 200),
  };
  console.error(safeError);
  process.exitCode = 1;
}