Car Doctor AI Stack

car-doctor-ai-stack.md

Car Doctor AI Stack

CarDoctorAI.com | Car Problem? Get Answers.

AI Chat

• Vercel AI SDK for streaming chat, tool calls, artifacts, and usage data
• OpenAI models for chat, reasoning, artifacts, and mechanic web search
• TokenLens for model usage enrichment

LLM Models

• OpenAI gpt-5.2 (varied reasoning effort) - chat-model, chat-model-reasoning, artifact-model, and findMechanic search with OpenAI web search
• OpenAI gpt-5-nano - title-model for chat title generation

AI Tools

• findMechanic - Search for local mechanics, relevant to chat transcript
• createDocument - Create custom, comprehensive, structured diagnostic report and other artifacts/documents
• updateDocument - Update existing artifacts
• requestSuggestions - Generate document suggestions
• getWeather - Get weather data (legacy)

Free/limited users have blocked versions of gated artifact tools

Authentication and Payments

• Auth.js / NextAuth credentials auth for registered and guest users
• Stripe Checkout for day passes and monthly subscriptions
• Stripe webhooks for subscription and day-pass entitlement updates

Database and Storage

• Neon Serverless Postgres for users, chats, messages, documents, votes, subscriptions, and streams
• Drizzle ORM and Drizzle Kit for schema, queries, and migrations
• Vercel Blob for uploaded file storage
• Vercel KV / Upstash Redis for chat rate limiting and resumable stream support

UI

• Next.js App Router with React Server Components and Server Actions
• React 19
• shadcn/ui with Radix UI primitives
• Tailwind CSS 4
• Framer Motion
• Lucide Icons
• Geist font

Core

• Next.js 16
• TypeScript
• pnpm
• Biome and Ultracite for formatting and lint checks
• Playwright for end-to-end tests
• Vercel Analytics and OpenTelemetry for production telemetry

Product Features

• Guest and registered chat sessions
• Automotive diagnostic Q&A
• Diagnostic report artifacts
• Local mechanic search by city
• Document, code, sheet, image, and diagnostic artifact types
• File uploads
• Chat history, votes, suggestions, and visibility controls
• Pricing page, dashboard, account deletion, and password changes

API Routes

• GET /api/auth/[...nextauth] - Auth.js route handler
• POST /api/auth/[...nextauth] - Auth.js route handler
• GET /api/auth/guest - Create guest session and redirect
• POST /api/chat - Stream AI chat response and save messages
• DELETE /api/chat - Delete a chat
• GET /api/chat/[id]/stream - Resume or fetch chat stream
• GET /api/history - Get chat history
• DELETE /api/history - Delete user chat history
• GET /api/document - Get latest or historical document versions
• POST /api/document - Save document version
• DELETE /api/document - Delete document versions
• GET /api/suggestions - Get document suggestions
• GET /api/vote - Get message votes for a chat
• PATCH /api/vote - Update message vote
• POST /api/files/upload - Upload file to Vercel Blob
• POST /api/checkout_sessions - Create Stripe checkout session
• POST /api/webhooks/stripe - Handle Stripe checkout and subscription webhooks
• POST /api/user/change-password - Change current user's password
• DELETE /api/user/delete-account - Delete current user account