nexus-mcp

A local MCP server for Nexus Mods mod discovery and research, backed by the v2 GraphQL API (api.nexusmods.com/v2/graphql). Read-only by design.

Tools

Adult content is always included — there is no filtering toggle.

Related MCP server: OSRS MCP Server

Setup

npm install
npm run build

Register with Claude Code:

claude mcp add nexus-mods -e NEXUS_MODS_API_KEY=<your key> -- node /home/matthew/src/nexus-mcp/dist/index.js

Or in Claude Desktop's claude_desktop_config.json:

{
  "mcpServers": {
    "nexus-mods": {
      "command": "node",
      "args": ["/home/matthew/src/nexus-mcp/dist/index.js"],
      "env": { "NEXUS_MODS_API_KEY": "<your key>" }
    }
  }
}

Authentication

NEXUS_MODS_API_KEY is optional — every tool works anonymously. When set (a personal API key), it is sent as the apikey header and unlocks viewer-relative fields (viewerEndorsed, viewerTracked, viewerDownloaded) on get_mod. See docs/adr/0001-personal-api-key-auth.md for why this server skips OAuth.

Development

npm run dev               # run from source via tsx
node scripts/smoke.mjs    # end-to-end smoke test against the live API (needs build)

Domain terminology lives in CONTEXT.md.