PACT

Semantic compression that beats ZIP by 40% on codebases.

pact.zip · Demo video · Explainer

https://github.com/hmatrades/PACT/raw/main/PACT_demo.mp4

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npx pact-cc setup     # one command. right-click + Claude Code compaction. done.

Quick start

pact pack myproject/          # 88 KB → 21 KB (4.2x)
pact inspect myproject.pact   # see functions, imports, types — no decompression
pact unpack myproject.pact    # restores myproject (1)/

Install

npx pact-cc setup

One command. Detects your OS. Installs everything:

• macOS — Finder Quick Actions (right-click → Pack with PACT) + native Swift progress UI
• Windows — right-click context menu via registry
• Linux — Nautilus, Dolphin, Nemo, Thunar scripts
• All platforms — Claude Code auto-compaction at 50% context

Why not ZIP?

ZIP compresses each file in isolation using 1993-era deflate. PACT:

• Solid brotli archive — all files compressed as one stream. Cross-file patterns compound the ratio.
• Semantic inspection — see functions, classes, imports without decompressing.
• 40% smaller than ZIP on real codebases.

ZIP:   362 KB
PACT:  221 KB — 40% smaller (79 files, measured)

Claude Code compaction

pact install --global     # auto-compresses every session at 50% context

	PACT	/compact
Compression	18.4x	4.0x
Retention	92%	68%
Lossy?	no	yes
API calls	0	0

12-task benchmark. Reproducible: node benchmarks/compaction-benchmark.mjs

BARUTU SNAKE

Task 012: PACT compressed the session that built PACT. 179 turns, 1.6M → 46K tokens, 34.3x lossless.

node benchmarks/run.mjs --tasks 012-barutu-snake

CLI

pact setup                           install everything, one command
pact pack <file|dir> [-o out.pact]   compress
pact unpack <file.pact> [-o path]    decompress
pact inspect <file.pact>             view contents
pact install --global                Claude Code auto-compaction
pact compact [text]                  compress context (no API)
pact --version                       version

Demo videos

Video	Description
PACT_demo.mp4	Full demo — pact pack, pact inspect, pact unpack, right-click integration, /pact slash command
pact-explainer.mp4	Animated explainer — what PACT does and why it beats ZIP

Development

npm install
npm run build          # tsup → dist/
npm test               # 150 tests (vitest)
npm run build:binary   # standalone macOS binary

Architecture

Files on disk
  → collect + sort by extension (similar files adjacent)
  → extract semantic summary per text file (functions, imports, types)
  → concatenate raw bytes into single buffer
  → brotli quality 11 (solid stream — sees patterns across all files)
  → .pact container
       PACT magic + version + manifest (uncompressed) + payload

The manifest stores per-file metadata and semantic summaries uncompressed — pact inspect reads the manifest without touching the brotli stream.

License

PolyForm Noncommercial 1.0.0 — source-available, noncommercial use only. Commercial license: heckeraiden@gmail.com

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pact.zip · Built with Claude Code · 150 tests passing