Onboarding

Learning a codebase you didn't build

New team, unfamiliar service, the person who built it has left. How to get your agent to walk you through one real request end to end, on the actual code.

You have joined the team that owns search, and the person who built it has left. The code is there, the docs are thin, and you are on call next week.

Follow one real thing, end to end

The fastest way into an unfamiliar system is not reading it top to bottom. It is following one real request from the outside in: what a user does, which service receives it, which lines decide what happens, and what comes back.

Pick a concrete case: "red running shoes under $80". Then follow it.

Ask for the journey, not the tour

A tour of the directories teaches you where files live. A journey teaches you how the system thinks. Ask your agent for:

1. a map of the parts this request touches
2. the code at each stop, in order
3. the numbers that were chosen (weights, limits, timeouts) and why

See it as you learn it

deck lets your agent give you that journey as something you click through. A map of the service, with the request's path drawn through it. The code at each stop, lit sentence by sentence. When you ask why popularity counts for 30 per cent, the answer comes back in the same window, sometimes as a chart of the experiment that chose the number.

You learn the system the way you would from the person who built it, at your own pace, and the questions you ask are pinned to the lines they are about.

Make it stick

• Follow two or three different requests, not one.
• End each one by writing down what you would change. That is the start of owning it.