This script/repo/tool does follow the automation guidelines on the /r/adventofcode community wiki.
Specifically:
Outbound calls are throttled to every 15 minutes in run_diff.
Once inputs are downloaded, they are cached locally remember_last_result and fetch_new.
The User-Agent header in fetch_new is set to me since I maintain this tool :)
This comes with a fly.io deployment config if you want it.
You will need to setup the following secreats:
AOC_BOARD_ID .. The ID of your private board.
AOC_SESSION .. Your session ID. Log in to AoC and watch the network traffic when getting your input to copy out the session cookie.
AOC_SLACK_HOOK .. Setup a Slack App, enable Incoming Web hooks and copy the URL listed.