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@@ -8,6 +8,8 @@ SmartUp is a web dashboard for monitoring API upstream rate groups and sending c
 
 **Sibling directories** (`new-api/`, `nox-api/`, `sub2api/`) are the Go-based AI API gateways that SmartUp monitors (upstreams) and syncs to (downstreams/websites). They are independent Go projects, not part of the SmartUp Python app. `browser-extension/` is a Chrome Manifest V3 extension for capturing auth credentials from real browser sessions.
 
+When the Python app's interaction with upstream/downstream APIs is unclear — e.g. auth flows, response shapes, endpoint behavior — read the relevant Go source in `new-api/`, `nox-api/`, or `sub2api/` to understand what the upstream/downstream expects.
+
 ## Tech stack
 
 - **Backend**: FastAPI (Python 3.12) + SQLAlchemy 2.0 (ORM, SQLite) + APScheduler