# USB — Universal Skill Bridge

> A portable skill format with sha256-verified installers that lets you write AI agent skills once and install them across 16 runtimes including Claude Code, Cursor, MCP, and LangChain.

USB (Universal Skill Bridge) is an open-source project by PeepSick Labs that solves the fragmentation problem in AI agent tooling: every runtime — Claude Code, Cursor, LangChain, MCP — invents its own way to package capabilities, so the same logic gets rewritten from scratch for each framework. USB provides a single portable skill format and a CLI installer that auto-detects your runtime and drops the right files into the right directories. The project is built in public under the MIT license and is currently in active beta (v0.4.7).

## What It Is

USB is an agent skill registry and cross-runtime installer. You define a skill once — with a trigger phrase, protocol prompt, input/output contract, and examples — and USB compiles it into every supported runtime's native format. The catalog ships with 529 skills spanning 65 engineering domains and 8 workflow types (Audit, Plan, Build, Script, Diagnose, Harden, Explain, Tune), plus 9 hand-written core orchestration skills. The installer is published on npm as `@peepsick/usb-cli` and is one command away: `npm install -g @peepsick/usb-cli && usb install`.

## Supported Runtimes and Targets

USB distinguishes between two tiers of runtime support:

- **Native installs** (the runtime loads these automatically): `claude`, `cursor`, `leosis`, `hermes`
- **Portable bundle emits** (skill markdown + JSON adapter descriptor under `~/.ai-skills/adapters/<target>/`): `openai`, `anthropic`, `langchain`, `mcp`, `openrouter`, `groq`, `mistral`, `ollama`, `lm-studio`, `vllm`, `generic`

The `auto` target detects the active runtime from your environment; `generic` falls back to plain markdown plus a JSON manifest for unrecognized runtimes. This covers 16 provider targets in total.

## Architecture and Trust Model

The system stores agent capabilities database-side (PostgreSQL via Drizzle ORM), independent of model or runtime. The key components are:

- **`/api/skills`** — compiles all 529 capabilities into a portable JSON bundle targeted at your platform
- **`/api/install`** — analyses your environment and writes the correct markdown, manifest, and rule files
- **`/api/install-sha256`** — provides a sha256 hash for verification before execution
- **`/api/mcp`** — an HTTP JSON-RPC 2.0 MCP server exposing `usb_search`, `usb_get_skill`, `usb_audit_skill`, and `usb_render_install` tools

The installer avoids raw `curl | bash` by default: the npm path is auditable like any package, and the curl path includes a sha256 verification step before execution. No telemetry is collected unless `USB_TELEMETRY=on` is set explicitly.

## Who It Is For

- **Claude Code users** — skills install into `~/.claude/skills/` as loadable `SKILL.md` files
- **Cursor users** — writes a `.mdc` rule into `.cursor/rules/`
- **AI teams** — one shared skill catalog instead of copy-pasted prompts across repos
- **MCP developers** — USB speaks MCP natively via its `/api/mcp` endpoint
- **Framework authors** — `@peepsick/usb-sdk` provides a typed `Agent` base class to build on

## Update: v0.4.7

The latest release (v0.4.7, published August 3, 2026) is described as a "consistency pass" aligning the README, landing page, and CLI. The project is actively evolving under a beta label, with APIs, skill formats, and runtime adapters subject to change before v1.0. The roadmap includes a skill marketplace, verified skill badges, CI-based skill validation, versioned skill contracts, and an agent runtime certification layer. PeepSick Labs describes itself as pre-incorporation and building in public, with USB sitting alongside two other planned layers: Foundry (multi-agent orchestration) and Leosis (an OpenAI-compatible LLM provider).

## Features
- 529-skill catalog across 65 engineering domains
- 16 supported agent runtime targets
- Auto-detection of installed agent runtimes
- sha256-verified installer scripts
- Native installs for Claude Code, Cursor, LeoSIS, and Hermes
- Portable bundle output for OpenAI, LangChain, MCP, Groq, Mistral, Ollama, and more
- npm CLI (@peepsick/usb-cli) with search, install, list, and info commands
- Dry-run mode for inspecting install scripts before execution
- MCP server endpoint with JSON-RPC 2.0 tools
- REST API for skills, install scripts, audit, version, and health
- PostgreSQL backend with Drizzle ORM
- No telemetry by default
- Typed Agent base class via @peepsick/usb-sdk
- Live playground for trying skills before installing
- Curated presets (e.g., web-dev) for bulk installs

## Integrations
Claude Code, Cursor, LeoSIS, Hermes, OpenAI Agents, Anthropic Messages API, LangChain, LangGraph, MCP (Model Context Protocol), OpenRouter, Groq, Mistral AI, Ollama, LM Studio, vLLM, PostgreSQL, Drizzle ORM, npm

## Platforms
CLI, API, WEB, DEVELOPER_SDK

## Pricing
Open Source

## Version
v0.4.7

## Links
- Website: https://usb.peepsicklabs.com
- Documentation: https://github.com/PeepSick/usb
- Repository: https://github.com/PeepSick/usb
- EveryDev.ai: https://www.everydev.ai/tools/usb-universal-skill-bridge