Capstone: Full AI Chat App
Putting it all together
This capstone combines every lesson: a Next.js API route calling Claude, a system prompt persona, streaming responses, persisted conversation history in Firestore, basic tool use, and a polished chat UI — deployed live on Vercel.
Build checklist
1. Define a clear persona for your app (e.g., an AI study buddy). 2. Wire streaming + persisted history. 3. Add one tool (e.g., a simple lookup function). 4. Add retry/error handling. 5. Deploy and test on the live URL.
What's next
From here you can add multi-agent architectures, RAG for document Q&A, or fine-tuned personas for specific industries. The foundation you built in this path applies to virtually any AI product you want to ship.
Key Takeaways
- You've built a full end-to-end AI chat app — API, persona, memory, UI, deployment.
- Every production AI app is built from these same core building blocks.
- Cost, error handling, and streaming are not optional — they're production requirements.
- This foundation transfers directly to agents, RAG, and other advanced patterns.
Ship your AI chat app
Combine everything from this path into one deployed app with a clear persona, streaming, persisted history, one tool, and error handling. Share the live link in the 404Fault community.