lcm-compact

lcm-compact is a command for Claude Code from lossless-claude/lcm. It costs 13 tokens per session (250 once invoked), scanned A, original, MIT.

A command that turns earlier conversation messages into linked summary notes, arranged so related information stays connected.

In plain words
What is it for?
Use it to summarize the current project’s conversations, summarize all projects, preview a compaction, or repeat compaction for sessions already summarized.
Why use it?
It reduces the amount of conversation text the coding agent must handle while keeping a way to recover the original detail. A preview option lets you check the result before anything is written.

Command for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the lcm plugin — 7 skills, 10 commands, 4 agents shipped together

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add lossless-claude/lcm
Claude Code
/plugin install lcm

Made for: Claude Code.

Or install lcm, the plugin that ships this one along with the rest of its 7 skills, 10 commands, 4 agents.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for lcm-compact

README.md
[![agentmods](https://agentmods.dev/badge/commands/lossless-claude/lcm/lcm-compact.svg)](https://agentmods.dev/commands/lossless-claude/lcm/lcm-compact)
Your own site
<a href="https://agentmods.dev/commands/lossless-claude/lcm/lcm-compact"><img src="https://agentmods.dev/badge/commands/lossless-claude/lcm/lcm-compact.svg" alt="Measured on agentmods" height="20"></a>
Per session 13 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 250 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00013 $0.00250
Opus 5 $0.00006 $0.00125
Sonnet 5 $0.00003 $0.00050
Haiku 4.5 $0.00001 $0.00025

Measured 6d ago against content hash 7400303250c7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

lcm-compact scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude-plugin/commands/lcm-compact.md · 38 lines

What it actually says

/lcm-compact

Compact unprocessed conversation messages into summarized DAG nodes.

Instructions

Run the following command via Bash:

lcm compact

If lcm is not on PATH (marketplace install), use the plugin-relative binary instead:

node "${CLAUDE_PLUGIN_ROOT}/lcm.mjs" compact

Options

Pass user-specified flags through to the command:

  • --all — Compact all projects (default: current project only). Forces batch compaction mode regardless of TTY environment, ensuring reliable behavior in automated tools.
  • --dry-run — Preview without writing
  • --replay — Re-compact sessions that already have summaries (by default, already-compacted sessions are skipped)

For example:

  • /lcm-compact --alllcm compact --all
  • /lcm-compact --dry-runlcm compact --dry-run
  • /lcm-compact --replaylcm compact --replay

Display the output verbatim.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 38 lines · 13 tokens per session scan A 7400303250c7

Subscribe to this mod's changes

lcm-compact is a command published in the GitHub repository lossless-claude/lcm (24 stars, last pushed 2d ago), licensed MIT. It adds 13 tokens to every session and 250 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.