GroundTruth MCP Server

Your AI assistant just mass-produced deprecated code again.You merged it because the formatting was clean.GroundTruth fixes that.

Self-hosted MCP server. 422+ curated libraries. 100+ audit patterns. No rate limits. No API keys.Ships updates continuously — your MCP client picks them up on restart.

The problem

Your model doesn't know that React 19 killed forwardRef, that Next.js made cookies() async, or that Tailwind v4 nuked @tailwind directives. It writes deprecated patterns with full confidence. It hands you SQL injection dressed up as a query builder and uses any in TypeScript like it's a feature.

GroundTruth runs on your machine. Fetches docs from the source — llms.txt, Jina Reader, GitHub — right when you ask. 422+ curated libraries, plus npm, PyPI, crates.io, and pkg.go.dev as fallback. The audit tool reads your actual files, finds issues at exact file:line locations, and fetches the current fix from the real spec.

Install

Claude Code

claude mcp add gt -- npx -y @groundtruth-mcp/gt-mcp@latest

Cursor / Claude Desktop / VS Code

Add to your MCP config (claude_desktop_config.json, .cursor/mcp.json, or .vscode/mcp.json):

{
  "mcpServers": {
    "gt": {
      "command": "npx",
      "args": ["-y", "@groundtruth-mcp/gt-mcp@latest"]
    }
  }
}

No build step. No config file. Node.js 24+. Using @latest means npx pulls the newest version on every session start — you always get the latest libraries, audit patterns, and fixes without doing anything.

Optional: GitHub token

GroundTruth fetches README files, release notes, migration guides, and code examples from GitHub. Unauthenticated requests are limited to 60/hr. A token with no extra scopes takes it to 5,000/hr.

# Claude Code
claude mcp add gt -e GT_GITHUB_TOKEN=ghp_yourtoken -- npx -y @groundtruth-mcp/gt-mcp@latest

# Cursor / Claude Desktop / VS Code — add env to your config:
"env": { "GT_GITHUB_TOKEN": "ghp_yourtoken" }

What it does

Twelve tools. Each does one thing.

How to use it

You don't need to memorize tool names. Just talk to your AI assistant.

use gt for nextjs
use gt for drizzle migrations
gt audit
use gt to check WCAG focus indicators
use gt for OpenTelemetry setup
find all issues and fix with gt
use gt for Google Gemini API
use gt for Claude tool use

Or call tools directly:

gt_resolve_library({ libraryName: "nestjs" })
gt_get_docs({ libraryId: "nestjs/nest", topic: "guards" })
gt_best_practices({ libraryId: "vercel/next.js", topic: "