OpenTelemetry just standardized LLM tracing. Here's what it actually looks like in code.

Every LLM tool invents its own tracing format. Langfuse has one. Helicone has one. Arize has one. If you built your own — congratulations, you have one too. OpenTelemetry just published a standard for all of them. It defines how to name spans, what attributes a tool call should have, how to log prompts without leaking PII, and which span kind to use for an agent. It's called GenAI Semantic Conventions. It's experimental. And almost nobody has written about what it actually looks like when you implement it. I know because I searched. "OTel GenAI semantic conventions" gives you spec pages. Zero practical articles. "How to trace LLM agent with OpenTelemetry" gives you StackOverflow questions with no answers. We implemented it. Four PRs, a gap analysis, real before/after code. We also discovered, mid-implementation, that our traces never exported at all — but that's a different story. Here's what the spec actually says, where we got it wrong, and what you should do today. The wild west of