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@@ -6,6 +6,8 @@ This file provides guidance to Claude Code (claude.ai/code) when working with co
 
 SmartUp is a web dashboard for monitoring API upstream rate groups and sending change notifications via webhooks (generic JSON / DingTalk bot). It supports multiple upstream auth types, periodic rate checking with APScheduler, snapshot diffing, and balance tracking with cost analysis.
 
+**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.
+
 ## Tech stack
 
 - **Backend**: FastAPI (Python 3.12) + SQLAlchemy 2.0 (ORM, SQLite) + APScheduler