| name | setup-mod |
| description | Step 2 of 4 of the Minecraft Java MCP setup. Download the minecraft-java MCP mod jar and its matching Fabric API jar and install both into the Minecraft mods folder. Use when the user has Minecraft Java with the Fabric loader ready and needs the MCP mod and Fabric API installed. |
Install the MCP mod + Fabric API (Step 2 of 4)
This is Phase 2 of the four-phase Minecraft Java MCP setup. It assumes
Phase 1 (setup-fabric) is done: Fabric is installed and the mods/ folder
exists. You should have, written down:
- the chosen Minecraft version (e.g.
26.1.2);
- the mods-folder path (single-player) or the
<server> root with its
mods/ folder (dedicated server).
If either is missing, get it before continuing. Work interactively — confirm
each download before moving on.
What you're installing
The MCP server is delivered as a Fabric mod. It needs exactly two jars in
mods/, both matching the same Minecraft version:
- The MCP mod —
minecraft-fabric-mcp-<modver>+<mc-version>.jar.
- Fabric API — the mod's only dependency.
Match the Minecraft version on both jars. A jar built for 26.1.2 will
not load on 1.21.11, and vice versa. The version suffix after the + must
equal the version chosen in Phase 1.
Step 1 — Download the MCP mod jar
From the mod's releases:
https://github.com/chapmanjw/minecraft-java-fabric-mcp-server/releases
Pick the asset whose filename ends in +<your-mc-version>.jar — e.g.
minecraft-fabric-mcp-0.1.0+26.1.2.jar for Minecraft 26.1.2. Pin to a specific
release tag rather than tracking latest, so the version stays in lockstep
with Minecraft and Fabric API.
Step 2 — Download the matching Fabric API jar
From Modrinth: https://modrinth.com/mod/fabric-api/versions
Filter by your Minecraft version and download the Fabric API jar for it — e.g.
fabric-api-0.149.1+26.1.2.jar. The exact Fabric API build doesn't have to be
the newest, but its Minecraft version must match.
Step 3 — Put both jars in mods/
Copy both jars into the mods/ folder from Phase 1.
Single-player — the platform path:
| OS | Path |
|---|
| Windows | %appdata%\.minecraft\mods\ |
| macOS | ~/Library/Application Support/minecraft/mods/ |
| Linux | ~/.minecraft/mods/ |
Dedicated server — <server>/mods/:
mkdir -p /opt/fabric-mcp/mods
The folder should now contain exactly these two jars (plus any other mods the
user already runs):
mods/
├── fabric-api-0.149.1+26.1.2.jar
└── minecraft-fabric-mcp-0.1.0+26.1.2.jar
Confirm with the user that both files are present and that the version suffixes
match each other and the Minecraft version.
Step 4 — Quick load check (optional but recommended)
If the user wants to confirm the mod loads before configuring it:
- Single-player: launch the Fabric profile and load any world.
- Dedicated server:
java -Xmx2G -jar fabric-server-launch.jar nogui.
In the log, look for the mod's startup lines:
[minecraft_fabric_mcp] MCP server config loaded from .../config/minecraft_fabric_mcp/config.json
[minecraft_fabric_mcp] Registered N MCP tools (M skipped due to version/module constraints)
[minecraft_fabric_mcp] MCP server listening at http://127.0.0.1:8765 (...)
Seeing the listening line means the mod loaded and the embedded MCP server
started. (Phase 3 covers configuring it and verifying /healthz.) If the game
crashes on load, the usual cause is a version mismatch between the mod jar, the
Fabric API jar, and Minecraft — re-check the +<version> suffixes.
Wrap up
Confirm with the user:
Hand off: Phase 2 is done — the mod is installed. The next step configures the
MCP server (config.json), launches it, and verifies it's reachable. Offer to
continue with the setup-server skill now.
