LangSmith is for the agent you are shipping: you instrument it, and every run becomes a trace with the full tree of steps, tool calls, latencies and token costs, plus the evaluation machinery to know whether it is getting better. If you are building on LangChain — or on anything, since it works without it — that is a serious platform for a serious problem.
PromptWake is for the agent that is writing your codebase. Nobody instruments Claude Code; it is a product you install, running under a developer's account, calling a vendor's API. There is no place to put a callback handler. What there is, is a transcript on disk — and that is what we read.
You cannot instrument software you did not write. What you can do is read what it already writes down.