Thanks for opening this issue @DevonFulcher !

It looks like the current error message is:

Semantic Manifest validation failed.

@Jstein77 do you have any recommendations for how we should proceed?

@dbeatty10 great Q! It depends what the validation error was. @DevonFulcher we probably throw an error here in DSI, can we thread that error message through here?

Hey @DevonFulcher, @dbeatty10, @Jstein77,

What do you think about raising an error inside the validate() method and making it return None instead of bool?
From what I checked, this behavior aligns with other validations in the project (example_1, example_2, example_3).

I've created a draft PR (#10128) with the implementation. If you think this approach is fine, I'll convert it to the normal PR.

Also, could you help me with these two points?

1. Could you hint at how to reproduce this issue locally in dbt-core CLI? I've created a semantic model in yml file. "Forgot" to add primary type to entities (I believe it should trigger this error), and then executed dbt run. But everything worked fine in the main branch.
2. I am hesitant about this point from the checklist. Could you help me understand if this change affects the interface?
   This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX

@Jstein77 can you answer question 1?

@Klimmy For question 2, this PR this PR has no interface changes, so I went ahead and updated that checklist item accordingly.

I've created a draft PR (#10128) with the implementation. If you think this approach is fine, I'll convert it to the normal PR.

Go ahead and flip the PR from "draft" to "ready" whenever you want, and we'll queue it up for one of our engineers to review the approach.

Hey, no worries, I was able to test it using dbt --no-partial-parse run. Everything works as expected from my side. I will convert the PR to "ready".
Thank you!