Introduction
This book is a learning roadmap tailored to one specific codebase: the FastVRP
route planning POC at /Users/leonlan/Dropbox/agents. It is written for a
backend engineer who needs to take that POC to a real product.
What you have today
- Backend: FastAPI + LangGraph ReAct agent (Claude Haiku 4.5, Gemini fallback), 12 tools that wrap a FastVRP solver client, in-memory session store.
- Frontend: React 19 + Vite, Leaflet map, SSE streaming chat, no state library (prop drilling), no TypeScript.
- Data: Scenarios held in a Python dict; instances are JSON files on disk.
- Deploy: Docker on a single GCE VM, nginx basic auth, Let's Encrypt cert.
The hard parts already work: the agent loop, the VRP schema, SSE streaming, and the solve-and-compare UX. The gap to "product" is almost entirely persistence, multi-user, and polish. It is not algorithm or agent work.
How to use this book
Each chapter covers one learning priority. Chapters are ordered by how much they unblock the rest of the work. Every chapter has the same shape:
- Why this matters in this codebase.
- What to learn, concretely.
- Resources worth reading.
- A hands-on exercise against the repo.
If you only have a weekend, read the Start here this week chapter and skip everything else.