fast-jev-compaction

# fast-jev-compaction

Claude Code plugin that replaces the compaction summary with Jev decisions:
every tool call and result is scored in one fast request, stale ones are
dropped or truncated, everything kept stays verbatim. Also usable as an npm
library.

## What and why

Most context compaction asks an LLM to summarize old turns. A summary is
lossy: a file path, exact error, constraint, or command can disappear even when
it matters later. This library never rewrites anything. It only deletes tool
calls and tool results Jev says are no longer needed, and it asks Jev while
showing it the whole conversation. User and assistant text stays verbatim and
in order.

The repository is both an npm package (`src/`) and a Claude Code plugin
(`hooks/`, `.claude-plugin/`) that uses the package to replace Claude Code's
built-in compaction summary with the original messages.

## How it works

1. Every `tool_use` is paired with its `tool_result` by `tool_use_id`. Calls in
   the first message or in the newest `preserveRecentMessages` messages are
   pinned and never touched.
2. The **state** sent to Jev is the whole conversation so far, oldest first,
   with every tool result replaced by a short note (`ok, 4213 chars (omitted)`).
   Tool inputs are included, texts are included, nothing is summarized.
3. The state is fitted into `maxStateTokens` (25k by default) in stages, each
   applied only if the previous one was not enough: tool inputs truncated to
   1000, then 200, then 60 characters; long texts abridged to head + tail,
   oldest non-pinned messages first; old non-pinned messages collapsed to a
   `[… N chars omitted …]` note; old tool calls reduced to one line each
   (`t12 Read file_path=src/a.ts → ok 480ch`); old call-less messages left
   out; runs of old call-only messages