Skilljack Client

What it does

Skilljack Client is an experimental full-capability MCP client built with Electron. It connects to MCP servers over stdio or HTTP, exposes a web UI for interactive exploration, and implements the full breadth of the MCP protocol — sampling, elicitation, roots, subscriptions, completions, and long-running tasks. It's designed to showcase what MCP Apps and server-side agents can do, and to serve as a reference implementation for MCP client developers.

Key features

• MCP Apps (SEP-1865) — Tool-provided HTML UIs rendered in sandboxed iframes on a separate port, with secure postMessage bridging
• Sampling — Handles server-initiated LLM requests with tool support, enabling full agentic server loops
• Elicitation — Server-driven user input via structured forms or URL redirects
• Multi-server mode — Connect to multiple MCP servers simultaneously via a JSON config file
• Conformance testing — Built-in --conformance flag for testing MCP server scenarios
• Customisable UI — Inspired by Winamp skins; designed to look however you want

Installation

Claude Desktop: Skilljack is a standalone MCP client, not a server — no claude_desktop_config.json entry needed. Run it alongside Claude to test MCP servers.

General setup:

git clone https://github.com/olaservo/skilljack-client
cd skilljack-client
npm install
npm run dev          # CLI mode
npm run dev:chat     # Web UI mode (browser at localhost:8080)
npm run electron:dev # Electron desktop app

Connect to a server:

# stdio
node dist/index.js --stdio "npx -y @anthropic-ai/echo-server" --sampling
# HTTP with web UI
node dist/index.js --url http://localhost:3001/mcp --sampling --web

Supported hosts

Standalone Electron desktop app and Node.js CLI — works alongside any MCP-compatible AI client.