🚀 Quickstart#

From nothing to a first paused function, in five steps. Every step is detailed in the VS Code page.

1. Install#

Sniffer is two pieces working together: the Fabric mod, running inside Minecraft, and the VS Code extension, driving it.

Mod: install Fabric Loader for your Minecraft version, then drop the Sniffer jar into your mods folder alongside Fabric API and Cloth Config (Kotlin support is bundled in the jar, no separate download needed).
Extension: install Sniffer (publisher Gunivers) from the VS Code Marketplace.

2. Configure#

Open your datapack folder, the one containing pack.mcmeta, in VS Code and accept the notification offering to add a debug configuration. It writes this .vscode/launch.json:

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "sniffer",
      "request": "attach",
      "name": "Connect to Minecraft",
      "address": "ws://localhost:25599/dap"
    }
  ]
}

On a multiplayer server, add "user" with your Minecraft username.

3. Attach#

Load your world, then run Connect to Minecraft from the Run and Debug view and accept the authorization dialog that pops up in game.

4. Set a breakpoint#

Open a .mcfunction file and click just left of a line number. You can also put a #!breakpoint directly in the function.

5. Run the function#

Call your function in game, with /function for instance. The execution halts before the marked command, and VS Code shows the call stack and the variables in scope. Drive it from there with Continue, Step Over, Step Into and Step Out.

Next: the VS Code page for the full debugging workflow, and the commands reference for everything Sniffer adds in game.