purse-first

A package framework for bundling CLIs, MCP servers, and skills into composable, Nix-built packages for humans and agents like Claude Code.

Architecture

purse-first has three layers:

Layer	Description
Protocol	A convention for Nix derivations to declare Claude Code capabilities via well-known paths under share/purse-first/
CLI	The purse-first binary — implements tool routing (hooks), marketplace generation, installation, and validation
Libraries	go-mcp and rust-mcp — building blocks for creating MCP servers that conform to the protocol

Package Flavors

Packages come in three flavors:

Flavor	Description	Examples
MCP package	Ships an MCP server with optional tool mappings	grit, get-hubbed, lux
Skill package	Ships skills only	robin, tap-dancer, bob
MCP + Skill package	Ships both MCP server and skills	chix

Current Packages

• grit (MCP) — Git operations via MCP: stage, commit, push, log, blame, and more
• get-hubbed (MCP) — GitHub CLI wrapper via MCP: issues, pull requests, and repos
• lux (MCP) — LSP multiplexer via MCP: hover, definitions, references, and symbols
• chix (MCP + Skill) — Nix MCP server and skills for Claude Code: build, evaluate, search, and manage flakes
• robin (Skill) — BATS integration testing skill with bundled assertion libraries, sandcastle isolation, and justfile patterns
• tap-dancer (Skill) — TAP-14 writer libraries (Go + Rust) and skill for producing spec-compliant TAP output
• bob (Skill) — purse-first's own skill package: plugin-mcp, context-saving, and go-cli-framework skills

Getting Started

purse-first packages are built with Nix and installed via the purse-first CLI. A marketplace is an aggregation of packages into a single Claude Code plugin (the .claude-plugin/ output).

Installation

# Install purse-first CLI
nix profile install github:friedenberg/purse-first

# Generate a marketplace from packages
purse-first marketplace generate --config marketplace-config.json --output ~/.claude/plugins/marketplace

For the complete protocol specification, see docs/purse-first-protocol.md.

Development

This is a Nix-based project. See the project-specific CLAUDE.md for build commands and architecture details.

# Build the project
just build

# Run tests
just test

# Format code
just fmt