@gnldev/docs-mcp

Stdio server that serves GNL docs to AI assistants over MCP (Model Context Protocol). Any MCP-compatible CLI or editor starts this server as a child process and can query GNL's features (install/API/example) with the gnl_docs_overview / gnl_docs_feature / gnl_docs_search tools.

Hand-written JSON-RPC 2.0 — @modelcontextprotocol/sdk is NOT USED (zero new dependencies: only node:readline/node:process). Content is first tried via a live fetch of /llms.txt + /llms-full.txt through GNL_DOCS_URL (default https://gnl.dev); if the network is unavailable/unreachable, it falls back to the static content embedded in the package (src/content.ts) — this package works on its own even if the site is down.

Install: the npx line below resolves straight from npm — or point your MCP client at a repo clone (pnpm install && pnpm -r build, then node packages/docs-mcp/dist/cli.js).

npm i -g @gnldev/docs-mcp   # or npx @gnldev/docs-mcp (no dependencies, runs the stdio server directly)

Adding via a CLI's mcp add

claude mcp add gnl-docs -- npx -y @gnldev/docs-mcp

Editors — mcp.json

{
  "mcpServers": {
    "gnl-docs": {
      "command": "npx",
      "args": ["-y", "@gnldev/docs-mcp"]
    }
  }
}

To run locally from within the monorepo (before publishing):

{
  "mcpServers": {
    "gnl-docs": {
      "command": "node",
      "args": ["/absolute/path/packages/docs-mcp/dist/cli.js"]
    }
  }
}

Environment variables

• GNL_DOCS_URL — doc source (default https://gnl.dev). Passing an empty string ('') has the same effect as GNL_DOCS_OFFLINE=1.
• GNL_DOCS_OFFLINE — if 1/true, the live fetch is skipped entirely and embedded content is always used (for tests and network-less environments).

Tools (tools/list)

• gnl_docs_overview() → GNL summary + ordered list of the features.
• gnl_docs_feature({ slug }) → installation/API/example detail for that feature (unknown slug → info text listing valid slugs, not a JSON-RPC error).
• gnl_docs_search({ query }) → simple (case-insensitive) text search.

How it works

src/cli.ts reads stdin line by line (node:readline) and hands each line to src/server.ts#handleMessage as a JSON-RPC 2.0 message; responses are written to stdout as single-line JSON (newline-delimited, the format expected by the MCP stdio transport). initialize → returns protocolVersion: '2024-11-05' + serverInfo; messages without an id field (notifications, e.g. notifications/initialized) are NEVER responded to, per JSON-RPC 2.0. Unknown method → -32601; in tools/call, an unknown tool/missing argument → a tool-level isError: true result (not a JSON-RPC error, per the MCP contract).

As a library (test/embedding): import { createDocsProvider, handleMessage, TOOLS } from '@gnldev/docs-mcp' — src/index.ts is the public export; the CLI's stdio side effects (process.stdin/process.exit) are kept in a separate file (src/cli.ts), so importing index.ts never starts a stdio server.

License

Apache-2.0 — see LICENSE.