TL;DR: Spring AI, LangChain4j, Koog (Kotlin), the Python OpenLLMetry-style instrumentations, and the Go OTel SDKs all emit gen_ai.* spans natively now. So you don't need a vendor SDK to make your agent observable — you need an OTLP endpoint that knows what to do with the spans your framework is already throwing on the wire. Here's what that looks like in three lines of YAML or one Kotlin extension. Someone on your team shipped an LLM agent two months ago. Today it ran up a $400 bill in twen...