dug into the actual session JSONL files and the breakdown is kind of absurd -- 60-70% is raw file contents from tool reads that claude already synthesized, another 15-20% is base64 thinking signatures. your actual conversation is like 10-15% of the window.
so i built cmv. it strips the junk and keeps every message verbatim. tool results over 500 chars become stubs, thinking sigs get removed, everything you said stays.
cmv trim --latest # trim and relaunch, 20-70% smaller (milage varies depending on tool and context session etc.)
cmv snapshot "analysis" --latest # save a session state
cmv branch "analysis" --name "auth" # fork from it later
also has a TUI dashboard that shows the token breakdown per session so you can see what's eating your context before you do anything.
what it's not:
* not a token monitor (ccusage etc already do that)
* doesn't touch original sessions, everything creates copies
* local only, reads JSONL directly, no API calls
curious how others handle this. most people seem to just accept /compact but losing a deep architectural discussion to a bullet point summary felt wrong enough to build something.