Ask HN: Good LLM Observability Platforms?

My company has been through 3 different "LLM Observability" vendors and they each have failed to give us the one (simple) thing we want. Willing to pay for this.

The ONLY thing we care about is the ability to: - Log an LLM completion, and be able to press a button that lets us re-run the exact same completion in a UI (industry seems to call this the "playground"). We can rerun this completion exactly how it was in production.

What we DO NOT care about: - "datasets" - "scores" - "prompt enhancers"