A Lens That Maps How Services Actually Talk

The architecture of 1 repo is easy, you can hold it in your head. The architecture of 5 repos talking to each other is the part that actually breaks, and it is the part nobody has written down. It lives in the gaps between the services, in the assumptions each side quietly made about the other. So I pointed a model at all of them at once, with 1 rule: every arrow on the diagram has to name the line of code that draws it.

What it actually is

/project-audit fans out across a set of repos at once and reads how they actually talk - not how a diagram on a wiki says they talk. Who calls whom, over what protocol, with what auth. It builds the real inter-service call graph and draws it as a node-box diagram with brand icons and auth labels, every edge traced to a real call site in the code. Then it surfaces the cross-cutting findings a single-repo audit can't see: the service that trusts a header another service forgot to set, the key that crosses a boundary it shouldn't.

The whole point is reading them together. Any one repo looks fine on its own. The problem is always the handshake.

In practice

I pointed it at a set of services I was sure I understood. The diagram it drew had an edge I'd forgotten existed - 1 service reaching directly into another's database instead of going through its API. Nobody wrote that down. Nobody would, because it felt obvious to whoever added it 2 years ago. It only shows up when you read every repo in 1 pass and let the call graph draw itself.

What I learned

The dangerous bugs almost never live inside a repo. They live in the seam between 2 of them, where each side quietly assumed the other was handling auth, or validation, or the edge case. A diagram that's honest about those seams - drawn from the code, not from memory - is worth more than any architecture doc that went stale the week after it was written.

The skill behind this is open source. Clone the 1 folder you need from bunlongheng/audits, point it at your own work, and draw the map of your own services and check every arrow.