Azure Functions Provider Error

I started up a previously working Azure functions project today that I hadn’t touched in a week. It failed to start with an error like this

A host error has occurred during startup operation 'b59ba8b8-f264-4274-a9eb-e17ba0e02ed8'.
api: Could not load file or assembly 'Microsoft.Extensions.Options, Version=, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified.
Value cannot be null. (Parameter 'provider')

This is the sort of error that terrifies me. Something is wrong but who knows what. No changes in git and an infinity of generic errors on google for Could not load file or assembly. Eventually after some digging it seems like I might be suffering from some corrupted tooling (some hints about that here: https://github.com/Azure/azure-functions-core-tools/issues/2232). I was able to fix mine by downloading the latest version of the tooling from https://docs.microsoft.com/en-us/azure/azure-functions/functions-run-local?tabs=v4%2Cwindows%2Ccsharp%2Cportal%2Cbash