Skillget

pi-lcm

agent
Security Audit
Warn
Health Warn
  • License — License: MIT
  • Description — Repository has a description
  • Active repo — Last push 0 days ago
  • Low visibility — Only 5 GitHub stars
Code Warn
  • process.env — Environment variable access in src/config.ts
Permissions Pass
  • Permissions — No dangerous permissions requested
Purpose
This agent provides lossless context management for the Pi CLI. It stores all chat messages in a local SQLite database and uses a hierarchical DAG-based system to summarize history without permanently deleting older context.

Security Assessment
The overall risk is Low. The tool does not request any dangerous permissions, execute arbitrary shell commands, or contain hardcoded secrets. It relies on a local SQLite database to store your conversation history. There is a warning regarding environment variable access in `src/config.ts`, but this is a standard and secure practice for managing local configuration settings. No suspicious outbound network requests were detected, meaning your chat data stays on your machine.

Quality Assessment
The project is highly active, with its most recent push occurring today. It is properly licensed under the standard MIT license, and its documentation is clear, detailed, and provides straightforward installation steps. However, community trust and visibility are currently very low. The repository has only 5 GitHub stars, indicating that it has not yet been widely tested or reviewed by the broader developer community. As a newer, niche tool, you are likely an early adopter relying primarily on the creator's code.

Verdict
Safe to use, but be aware that it is an early-stage project with minimal community oversight.
SUMMARY

Lossless Context Management for Pi. DAG-based summarization with full history recovery.

README.md

pi-lcm

Lossless context management for Pi. Never lose a message again.

License: MIT npm version TypeScript Pi 0.58+ PRs Welcome

Install · Quick Start · How It Works · Features · Configuration · Contributing

Pi's default compaction throws away old messages when the context window fills up. A single flat summary replaces everything, and the original messages are gone forever.

pi-lcm fixes this. Every message is stored permanently in SQLite. When compaction triggers, messages are summarized into a hierarchical DAG (directed acyclic graph) instead of a flat blob. The agent can search and drill back into any compressed node to recover the original detail.

Install

# From npm
pi install npm:pi-lcm

# From source (development)
git clone https://github.com/codexstar69/pi-lcm.git
cd pi-lcm
bun install
pi -e ./index.ts

Quick Start

Install the extension and start Pi. That's it. pi-lcm works automatically:

  1. Every message is persisted to SQLite as it happens
  2. When Pi triggers compaction, pi-lcm creates hierarchical DAG summaries instead of flat text
  3. The agent gets three tools to recover detail from compressed history

No configuration needed. Default settings work well for most sessions.

How It Works

Pi Session
│
├── message_end ──► SQLite (every message stored permanently)
│
├── session_before_compact ──► CompactionEngine
│   ├── Leaf pass: raw messages → D0 summaries (parallel, 4 workers)
│   ├── Condensed pass: D0 → D1 → D2+ (cascading until stable)
│   └── Assembly: DAG summaries → token-budgeted output for Pi
│
├── before_agent_start ──► Static system prompt preamble (cache-safe)
│
└── registerTool ──► lcm_grep, lcm_describe, lcm_expand

The DAG grows logarithmically. With a condensation threshold of 6, you need 7 compaction cycles to get a D1 summary, 43 to get D2, 259 to get D3. A conversation can run for thousands of turns and the DAG stays compact.

Prompt caching is preserved. The system prompt preamble is a static const string, identical every turn. Dynamic stats go in the compaction summary message (which only changes on compaction). Zero extra cache misses.

Features

Message Persistence

  • Every AgentMessage stored in SQLite with FTS5 full-text search
  • Idempotent inserts via dedup_hash (safe for session resume)
  • Atomic sequence numbers via INSERT...SELECT (no race conditions)
  • Per-project database (cross-session history within the same project)

DAG Compaction

  • Two-phase: leaf pass (messages → D0) then condensed pass (D0 → D1 → D2+)
  • Parallel leaf summarization (configurable concurrency, default 4)
  • Bounded cascade loop (max 10 passes per cycle)
  • Consumed summaries filtered via NOT EXISTS (no re-condensation)
  • Failed chunks stay uncompacted for retry next cycle (no data loss)
  • Per-conversation mutex prevents duplicate summaries

Agent Tools

Tool Purpose
lcm_grep Search all history by text (FTS5) or regex. Returns snippets with context. Time-range filtering.
lcm_describe Overview of the summary DAG, recent/earliest activity, or detail on a specific summary ID.
lcm_expand Drill into any compressed summary to recover original messages. Hard 8K token cap. Cycle-safe.

Security

  • XML-fenced content in summarization prompts (prompt injection mitigation)
  • FTS5 query sanitization (no syntax injection)
  • Regex execution with 50K char cap per message (ReDoS mitigation)
  • DB directory permissions: 0o700 dir, 0o600 file
  • Path validation on LCM_DB_DIR (no traversal)

Settings TUI

  • /lcm-settings opens an interactive overlay panel
  • Toggle, adjust, and edit all settings with keyboard navigation
  • Global or project-scoped settings (.pi/settings.json)
  • Changes apply instantly, no restart needed

Configuration

Open the settings panel with /lcm-settings, or edit ~/.pi/agent/settings.json directly:

{
  "lcm": {
    "enabled": true,
    "leafChunkTokens": 4000,
    "condensationThreshold": 6,
    "maxDepth": 5,
    "maxSummaryTokens": 8000,
    "minMessagesForCompaction": 10,
    "leafPassConcurrency": 4,
    "debugMode": false
  }
}
Setting Default Description
enabled true Enable/disable the extension
leafChunkTokens 4000 Token budget per leaf summary chunk
condensationThreshold 6 Number of summaries at one depth before condensing up
maxDepth 5 Maximum DAG depth levels
maxSummaryTokens 8000 Token budget for the assembled compaction output
minMessagesForCompaction 10 Skip DAG compaction if fewer messages (falls back to Pi default)
leafPassConcurrency 4 Parallel workers for leaf summarization
debugMode false Verbose logging and notifications

Environment variables also work: LCM_ENABLED, LCM_LEAF_CHUNK_TOKENS, LCM_DEBUG, etc.

Project-level settings (.pi/settings.json) override global settings.

Commands

Command Description
/lcm stats Show message count, summary count, DAG depth, DB size
/lcm tree Visualize the summary DAG
/lcm compact Trigger manual compaction
/lcm settings Open the settings panel
/lcm-settings Open the settings panel (standalone)

Compaction Models

pi-lcm uses a cheap fast model for summarization, not your session model. It tries in order:

  1. cerebras/zai-glm-4.7 (fast, free)
  2. anthropic/claude-haiku-4-5 (reliable fallback)
  3. Session model (last resort)

Configure custom models in settings.json under compactionModels.

Development

git clone https://github.com/codexstar69/pi-lcm.git
cd pi-lcm
bun install
bun run test          # 46 tests
pi -e ./index.ts      # Load in Pi for testing

Contributing

See CONTRIBUTING.md for development setup and guidelines.

Security

See SECURITY.md for reporting vulnerabilities.

License

MIT. See LICENSE.

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