VitaminMCP

VitaminMCP

Test your plugins with an AI agent — on a real running server, with real players.

Documentation · Modrinth · npm · Issues

VitaminMCP is a Paper/Purpur plugin that opens an MCP (Model Context Protocol) endpoint from inside your running server. Connect an AI agent — Claude Code, Cursor, Codex, Gemini CLI, any MCP client — and it can drive the server and read back what happened, while real bot clients join over the actual Minecraft protocol.

Nothing about the plugin you are testing changes. No test framework to adopt, no source to instrument, no mock server: the plugin under test runs on a real server through its real lifecycle. That also means it works on plugins you did not write — anything installed is testable.

What the agent can do

• Spawn and control test players — real protocol clients, not mock Player objects
• Execute commands as the console or as a player
• Open, read, click and assert on inventories and plugin GUIs
• Right-click NPCs and villagers, the way a shop or quest giver is actually triggered
• Move players, break and use blocks, chat
• Wait for events and conditions instead of sleeping
• Read the player's whole screen: menus, chat, action bar, titles, boss bars, scoreboard
• Read live server state: events, logs, exceptions, permissions
• Drive several servers at once — one session per backend of a BungeeCord network

MCP tools

Scenario steps

bot_run_scenario scripts a whole test from these steps — a failure reports the failing step and what the server was doing at that moment:

How the three pieces fit together, what every tool and step accepts, and an example scenario are in docs/reference.md.

Version support

Runner support by operating system

Legend: 🟢 supported · 🟡 planned or requires the stated runtime · 🔴 unsupported.

Requirements, where each claim comes from, and how the version matrix is run are in docs/reference.md.

Setup

1. Install the plugin — download VitaminMCP.jar from the latest release (or from Modrinth), drop it into plugins/, and start the server.

2. Add the MCP server to your AI client — it runs on your machine, not on the server:

Claude Code

claude mcp add vitaminmcp -- npx -y vitaminmcp

Claude Desktop, Cursor, or any client with a JSON MCP config:

{
  "mcpServers": {
    "vitaminmcp": {
      "command": "npx",
      "args": ["-y", "vitaminmcp"]
    }
  }
}

It is also on the official MCP registry as io.github.Backas03/vitaminmcp, so clients with a registry catalogue can add it from there.

Clients that keep one stdio process per loaded project can instead connect all projects to one shared loopback server. On Windows, npx -y vitaminmcp service install installs and verifies that shared server in one command.

3. Let the agent wire itself up — ask it to run the setup prompt (in Claude Code: /mcp__vitaminmcp__setup). It finds the running server, checks the plugin, and connects.

That is enough for a server on this machine. The Claude Code plugin (which also brings the testing skill), other clients, installing from the jars, config.yml defaults, bot setup, and reaching a server behind SSH or TLS are all in INSTALL.md.

Full installation and usage docs: backas03.github.io/VitaminMCP — every tool, scenario runs, multi-server sessions, and remote-server setup are covered in docs/usage.md.

Contributing and building

Contribution rules are in CONTRIBUTING.md, building from source in docs/reference.md, and release steps in docs/publishing.md.

License

MIT — see LICENSE. The third-party code bundled in the jars, and its licenses, are listed in docs/reference.md.