Create your own protocol. I created a "wind down session" protocol my agents use that takes detailed notes in a "next_session_prompt.md" file that covers what was done this session, what is still open, and where they need to pick up the next session.

You can refine the protocol as you realize what's working and what isn't. I've been using that for months and it rarely drops important things now.

I'm fed up with compaction. I want my agent to get compacted but also retain full access to the prior conversation via search and tool calls - I want it to know "the requirements for X were discussed in detail previously in conversation C51E31CE-C985-4633-A749-DCC9805A7FEB" and have a tool that lets it dispatch a subagent to find those details again.

Do any of the coding agents have this already?

Just make a new slash command with those instructions as the prompt.

Have you tried Matt Pocock's "handoff" skill?

There is, but your wish of "clean" is ambiguous.