I don't like any of current solutions when it comes to compaction. I'd love to have a way to say what exactly should be summarized, because most of the time I just need to compact some noisy MCP tool calls, test runs and things like that. Just let me pick what should be summarized and keep the rest as is.

You can do that in Pi!

> Extensions can intercept and customize both compaction and branch summarization

https://pi.dev/docs/latest/compaction

Just make an extension (or ask Pi to write an extension for itself) that intercepts compaction and leaves only what you want, or rewrites it in any other way. Should be just a few lines.

I think /handoff on pi (or at least oh my pi) is what you are looking for

Sounds like you might like subagents. Agent > subagent receives agent context (presumably cached)->tool call->compact/summarise->return to main agent