Consider inverting the logic here, i.e. having IsPropertyLoaded which defaults to true - IsPropertyNotLoaded means double negation by default (loaded) which is confusing.

It's more efficient as most properties are loaded, so we don't need to change from the default value. Also, this distinguishes it from IsLoaded above. In any case, this is something that noone will ever look at again until we add another flag (unlikely)

Not sure what our regular practice here is, but is it worth having a convention that does nothing by default, just as a base class? It seems like this doesn't add much value beyond just having each provider add its own convention...

Also, don't you generally prefer avoiding IModelFinalizingConvention and doing this kind of thing reactively?

Not sure what our regular practice here is, but is it worth having a convention that does nothing by default, just as a base class? It seems like this doesn't add much value beyond just having each provider add its own convention...

Provider-specific conventions won't be needed after #36350. Adding it here now prevents a provider-break later.

Also, don't you generally prefer avoiding IModelFinalizingConvention and doing this kind of thing reactively?

Yes, but again, that requires vector-specific API (#36350)

I posted a question on the Cosmos channel to ask if there's anything we can do here. But in any case, I'm guessing the only practical guidance to users would be to split their embedding to a separate item (possibly in a separate container), which you only use when doing similarity search; this way, all other workloads are oblivious of embeddings, and when you do similarity search you do one search and then one ReadItem point read.

Maybe add a sentence about this to the user (ideally Cosmos would simply have this guidance in their docs and we'd point to it)

I mainly just scoped this out for 11. We can mention this in the documentation

I never fully understood why type mappings are sometimes unavailable in conventions, but matching on the type like this isn't great - we have an issue for allowing more types here (#37025), and it would be better not to have to update this convention... Plus in theory someone could value-convert to a vector type (very contrived, I admit).

Vector-specific API will be added in #36350

nit: remove curlies and put on one line (elsewhere too)

The XML doc comment has two consecutive sections (lines 11-16). Duplicate XML doc tags can produce documentation warnings/errors; merge these into a single block (and keep the constructor sentence inside it, or move it to

The XML doc comment contains duplicate tags (lines 13-18). This can trigger XML documentation warnings; combine into a single element (or move the constructor note elsewhere).

SetIsAutoLoaded uses IsAutoLoaded != autoLoaded to detect changes. When autoLoaded is null (reset to default), this comparison is always true (bool vs bool?), so conventions will run even if _isAutoLoaded is already null and no effective change occurred. Consider comparing _isAutoLoaded to autoLoaded (both nullable) or otherwise special-casing null resets so OnPropertyAutoLoadChanged only runs when the stored value actually changes.

The XML doc summary for AutoLoadedCosmosProperty doesn't match the actual resource string in CosmosStrings.resx (the summary mentions storing JSON documents, while the resx value doesn't). Since this file is auto-generated, regenerate CosmosStrings.Designer.cs from the .resx (or update the .resx text to match) to keep them consistent.

Line 210 contains trailing whitespace. Please remove it to keep formatting clean and avoid noisy diffs in future edits.