PackWarden — Thunderstore Mod-Pack MCP Server (v0.1.0)

PackWarden is not affiliated with or endorsed by Thunderstore. "Thunderstore" is used only to describe compatibility. Mod data comes from the public Thunderstore API (https://thunderstore.io).

An MCP server that helps AI assistants build and maintain Thunderstore mod packs (Lethal Company, Risk of Rain 2, Valheim, and every other Thunderstore community).

Tools

Mods are referenced as Owner-Name (latest) or Owner-Name-1.2.3.

Related MCP server: nexus-mcp

Install

Requires Node.js ≥ 18.17.

git clone <repo> thunderstore-mcp && cd thunderstore-mcp
npm install && npm run build

Claude Desktop

Edit claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\):

{
  "mcpServers": {
    "thunderstore": {
      "command": "node",
      "args": ["/absolute/path/to/thunderstore-mcp/dist/main.js"],
      "env": { "TSMCP_EXPORT_DIR": "/absolute/path/for/profiles" }
    }
  }
}

Restart Claude Desktop.

Cursor

~/.cursor/mcp.json (global) or .cursor/mcp.json (project):

{
  "mcpServers": {
    "thunderstore": {
      "command": "node",
      "args": ["/absolute/path/to/thunderstore-mcp/dist/main.js"]
    }
  }
}

Streamable HTTP (remote / self-hosted)

npm run start:http            # http://127.0.0.1:3333/mcp
PORT=8080 HOST=0.0.0.0 node dist/main.js --http

Cursor: { "mcpServers": { "thunderstore": { "url": "http://127.0.0.1:3333/mcp" } } }. The HTTP mode is stateless (POST-only, JSON responses) and has no auth. Put it behind a reverse proxy with TLS and auth before exposing it.

Configuration (env)

Be a good API citizen

• One full package list download per community per TTL, then conditional requests (If-Modified-Since). Results are cached on disk as a slim index.

• Outbound requests are serialized (concurrency 1) and spaced ≥1s apart. On 429/5xx the client backs off and honours Retry-After.

• Identifying User-Agent with a contact address.

• If the network fails, the server keeps serving stale cache.

Tests (live API)

npm test                         # default community: valheim
TEST_COMMUNITY=valheim npm test

Tests cover stdio and streamable HTTP end-to-end against the live Thunderstore API.

Limitations

• Large communities are heavy. The first load of Lethal Company is about 330 MB of JSON, takes about 14 s, and uses about 1.4 GB of RAM. After that, loads from cache take about 3 s.

• Resolution follows r2modman behaviour (highest requested version wins). It does not do semver range solving, because Thunderstore pins exact versions.

• No profile code sharing, which would need an upload to Thunderstore. Only file export is supported.

• Search is local keyword scoring, not Thunderstore's own search ranking.