USB — Universal Skill Bridge

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).