AI Observability: Logs, Prompts, Tool Calls, And Cost

Here's a five-line function. It calls an LLM, logs the answer, returns it. async function ask(question: string) { const res = await openai.responses.create({ model: "o4-mini", input: question }); console.log("answer:", res.output_text); return res.output_text; } This compiles. It passes tests. It ships. And it will quietly cost you four figures a month before anyone notices, because nothing in that log tells you the model burned 8,000 hidden reasoning tokens to produce a 40-token...