How structure this sentence to make it easier to read?

Question

I am a non-native speaking developer and when I am writing documentation of some data structure I usually use the following sentence structure as a definition of a property:

ID of the contract this service is defined in.

This sentence tries to tell that the contractId property on my Service object, is pointing to a Contract which contains this service. However, this sentence is hard to read and have a strange structure. By strange structure I mean the two subject of the sentence follows each other and the verb is at the end, this makes it harder to understand for me.

My question is how can I write this with an easy to understand wording. (So while scanning through the file, I can understand it without reading the full sentence carefully.)

PS: Sorry for the meaningless title, I could not think of any better one.

Answer 1

This sentence has a dangling preposition ("in") which can make it hard to parse.

I would suggest this improvement:

ID of the contract where this service is defined.

Answer 2

You could also write:

ID of the defining contract.