It is designed as a replacement for legacy EterPack tooling when you control the client source and want a format that is easier to automate and harder to tamper with.

Goals

CLI workflow first, no GUI dependency
deterministic manifest layout for automation
zstd compression
XChaCha20-Poly1305 authenticated encryption per file
Ed25519 signed manifest for tamper detection
JSON output for AI agents and automation
no real content master key embedded in the client header

Current commands

m2pack keygen
m2pack build
m2pack diff
m2pack list
m2pack verify
m2pack extract
m2pack export-client-config

MCP Server

The repository also ships a Linux-friendly MCP server that wraps the m2pack CLI for AI agents and automation.

Files:

mcp_server.mjs
package.json

Install:

npm install

Run:

npm run mcp

If the m2pack binary is not at build/m2pack, set:

export M2PACK_BINARY=/absolute/path/to/m2pack

Exposed tools:

pack_keygen
pack_build
pack_diff
pack_list
pack_verify
pack_extract
pack_export_client_config
pack_binary_info

Smoke test:

npm run mcp:smoke

Python MCP Server

If you prefer Python over Node for the MCP wrapper, the repository also ships a Python FastMCP variant.

Setup:

python3 -m venv .venv-mcp
. .venv-mcp/bin/activate
pip install -r requirements-mcp.txt

Run:

python mcp_server.py

Python smoke test:

python scripts/mcp_smoke_test.py

Build

cmake -S . -B build
cmake --build build -j

Quick start

Generate a master content key and signing keypair:

./build/m2pack keygen --out-dir keys --json

Build an archive from a client asset directory:

./build/m2pack build \
  --input /path/to/client/root \
  --output out/client.m2p \
  --key keys/master.key \
  --sign-secret-key keys/signing.key \
  --json

Verify the archive:

./build/m2pack verify \
  --archive out/client.m2p \
  --public-key keys/signing.pub \
  --key keys/master.key \
  --json

Extract:

./build/m2pack extract \
  --archive out/client.m2p \
  --output out/unpacked \
  --key keys/master.key

Export a client config header for m2dev-client-src/src/PackLib/M2PackKeys.h:

./build/m2pack export-client-config \
  --key keys/master.key \
  --public-key keys/signing.pub \
  --output /path/to/m2dev-client-src/src/PackLib/M2PackKeys.h

Diff a source tree against an archive:

./build/m2pack diff \
  --left /path/to/client/root \
  --right out/client.m2p \
  --json

Format summary

Single archive file with a fixed header
Binary manifest near the end of the file
Signed manifest hash in the header
Per-file random nonce
Per-file AEAD ciphertext, authenticated with the relative file path

See docs/format.md and docs/client-integration.md. For Codex and Claude Code MCP setup, see docs/agent-setup.md.