TruthCheck Docs

Prerequisites

• Node.js 20+
• DeepSeek API key — platform.deepseek.com
• Brave Search API key (optional — required on Vercel/cloud where DuckDuckGo is blocked)

Setup

git clone <repo-url>
cd truth-checker
npm install

# Copy and fill in environment variables
cp .env.example .env.local
# Required: DEEPSEEK_API_KEY
# Optional: BRAVE_SEARCH_API_KEY

npm run dev

App available at http://localhost:3000

Common Commands

npm run dev          # Start dev server
npm run build        # Production build
npm run start        # Start production server
npm run lint         # ESLint
npm test             # Run all tests (Vitest)
npm run test:watch   # Watch mode

Adding a Translation Key

1. Add the English string to dict.en in lib/i18n.ts
2. Add the Spanish string to dict.es with the same key
3. Use it in any client component: const { t } = useLanguage(); t('my_key')

The test suite automatically enforces that dict.en and dict.es have identical keys.

Styling

Tailwind CSS v4. Custom utility classes in app/globals.css:

• .glass — glassmorphism with backdrop blur
• .gradient-text — indigo-to-cyan gradient text
• .hero-pattern — radial dot grid background

Docker

docker compose up -d --build   # Build and start
docker compose down             # Stop

POST/api/extract

Extracts atomic factual claims from a body of text using deepseek-chat.

// Request
{ "text": "...", "language": "en" }

// Response
{ "claims": [{ "id": "claim-0", "text": "...", "originalTextQuote": "..." }] }

POST/api/verify

Verifies a single claim via web search + DeepSeek Reasoner. Pass "language": "es" to receive reasoning in Spanish.

// Request
{ "claim": { "id": "claim-0", "text": "...", "originalTextQuote": "..." }, "language": "en" }

// Response
{ "result": { "claimId": "claim-0", "score": 0, "reasoning": "...", "sources": [...] } }

Score Interpretation