What is lossless-compact?
lossless-compact is a Claude Code mod by MusicStudioNYC that lossless compaction for Claude Code: nothing is summarized; everything removed is archived verbatim with provenance and restorable by id (Jev or a local ruleset). /lossless to inspect and. It is listed under Context & memory and has 2 GitHub stars.
| Type | Claude code mod |
|---|---|
| Author | MusicStudioNYC |
| Repository | MusicStudioNYC/lossless-compact |
| Popularity | 2 GitHub stars |
| Category | Context & memory |
| Security | High risk (44/100) |
| Rank | #1,356 of 5,272 Claude Code mods; #144 in Context & memory |
| License | MIT |
| Last commit | 2026-10-07 |
| Hooks | 6 events |
| Sees | compaction, every prompt, every skill |
| Draws on | nothing |
Is lossless-compact safe to install?
lossless-compact scores 44/100 on the MCPMods security check: High risk. Things to review: sends data over the network; writes files or config; reads environment variables; watches every prompt or event. It passed 2 of 8 checks.
Mod footprints come from claude plugin validate, which lists every event a mod hooks and every API call it makes without running it.
| Check | Result |
|---|---|
| Sends data over the network | Review |
| Starts no processes | Pass |
| Writes files or config | Review |
| Reads environment variables | Review |
| Watches every prompt or event | Review |
| Drives Claude (model calls, prompts) | Note |
| Validator reported problems | Note |
| Has an open-source license | Pass |
API calls in its code
| Call | What it means |
|---|---|
$.command.register | |
$.command.run | drives Claude |
$.env.get | reads env vars |
$.fs.exists | reads files |
$.fs.list | reads files |
$.fs.read | reads files |
$.fs.write | writes files |
$.http.fetch | network requests |
$.model.complete | drives Claude |
$.model.fork | drives Claude |
$.session.compact | drives Claude |
$.session.cwd | |
$.session.id | |
$.session.messages | reads the transcript |
$.session.usage | |
$.settings.read | reads settings |
$.store.get | keeps its own state |
$.store.set | keeps its own state |
$.ui.ask | draws interface |
$.ui.log | draws interface |
$.ui.toast | draws interface |
How do I install lossless-compact?
- Check your Claude Code version. Mods need Claude Code 2.1.287 or later and are on by default.
claude --version
- Read its footprint. This lists every event it hooks and every API call it makes, without running it.
git clone https://github.com/MusicStudioNYC/lossless-compact claude plugin validate ./lossless-compact/.
- Install it. Run this in your terminal, then /reload-plugins in an open session.
claude plugin marketplace add MusicStudioNYC/lossless-compact && claude plugin install lossless-compact@lossless-compact
Or ask Claude to set it up
Paste this into Claude Code and it installs lossless-compact for you:
Install the "lossless-compact" Claude Code mod from https://github.com/MusicStudioNYC/lossless-compact. Run claude plugin validate on it first and show me what it can access before you enable it.