fast-jev-compaction

fast-jev-compaction changes what happens when a long Claude Code session runs out of room. The built-in behavior summarizes old conversation, which loses detail. This plugin asks Jev, a decision model from TypeSafe AI, which old tool calls and outputs are stale, deletes only those, and keeps every user and assistant message word for word. MIT licensed.

Install goes through the Claude Code plugin marketplace, straight from the repo. It needs an environment flag for function hooks, which the README calls an early-access Claude Code feature, plus a TypeSafe API key. Jev bills $0.042 per million input tokens and is waitlisted. When Jev errors out or does not cut enough, the plugin falls back to the normal summary.

Solo developers living in long Claude Code sessions are the audience, once they have Jev access. Teams should think harder, because the plugin sends your session transcript to TypeSafe for scoring.

The catch: do not run the npm install line in the README. As of September 21, 2026, the fast-jev-compaction name on npm belongs to a different account publishing its own fork with extra command line tools. Nothing in it looked malicious on a static read, but it is not the author's package. The marketplace path pulls from the repo and is unaffected. Token sizes are also estimated from character counts, and users report the hooks not loading on some Claude Code versions.