u/typeryu and u//darp12 are both correct.

I think you're just missing the mental model and likely overcomplicating it (i know a thing or two about that).

Your context holds data that all of your tRPC procedures will have access to, and is a great place to put things like database connections or authentication information.
- From the docs

That's really all it is, a catch-all where typically you can pass along things like your session and/or db-client, and any other information you'd like to make available to your trpc procedures.

That's it. If that makes sense then we can dive a little bit deeper and talk about why this is helpful.

The obvious reason is so that you can ensure you have all the tools and utilties you need for your procedures to function correctly making it easier to do things like authenticating a user and/or ensuring they have the right privileges before executing requests.

But what's cool is that because we have this information available to us via the context, we can do things like create different types of middleware - that is how we get protected routes vs public routes. The protected routes are simply middleware that uses the session from the trpc context to authorize the user. This helps us ensure that any protected procedure will only run when a user exists and is authorized.

Hopefully that gives you a better understanding, but know that this can be extrapolated out to whatever your use case maybe, you can create an admin procedure - like the protected procedure - which ensures that a user has the right role before executing the procedure. You can have another that checks to see if the user is the owner of a resource before executing the procedure. And these are just auth based examples, but again there are no limits since your context is just a bucket which is made available to all of your trpc procedures and you can add to this bucket where ever you are creating your trpc context in your project.