updates copilot instructions for agents

Author: wasin-waeosri

.github/copilot-instructions.md

@@ -4,6 +4,19 @@
 
 A step-by-step Copilot guide to set up a [Data Library for Python](https://developers.lseg.com/en/api-catalog/lseg-data-platform/lseg-data-library-for-python) development environment with Python and JupyterLab on Windows and macOS.
 
+See [README.md](../README.md) for full project context, architecture diagrams, and rate-limit details.
+
+---
+
+## Agent Notes (Key Conventions)
+
+- **Main notebook**: `notebook/ld_notebook_async_gather.ipynb` — the primary working notebook for concurrent async historical pricing requests using `asyncio.gather()`.
+- **Credentials**: Copy `notebook/.env.example` → `notebook/.env` and fill in `LSEG_API_KEY`, `LSEG_MACHINE_ID`, and `LSEG_PASSWORD`. Never commit `.env`.
+- **Library version**: `lseg-data==2.1.1` is pinned in `requirements.txt`. Do not upgrade without testing — API behavior may change.
+- **Rate limits**: The Data Platform enforces per-account request-per-second limits. HTTP **429** errors mean too many concurrent requests — reduce concurrency and retry. See [README.md](../README.md) for details.
+- **Logging**: `notebook/lseg-data.config.json` controls Data Library logging. File and console logging are disabled by default; enable them there for debugging.
+- **Virtual environment**: Always use `.venv` at the workspace root. Never install packages globally.
+
 ## Prerequisites
 
 - Python 3.11 or higher installed and available on your `PATH`