What is the correct form to express the agnostic quality of something. The usual suffix -ness seems incorrect to me but I could not find a trustworthy reference to either confirm or deny this.

The only derived form I have encountered is the noun agnosticism

To describe my desired use case in an example:

This system is comprised of a portal and a service
The portal needs to be fully agnostic of the service
The agnosticness/agnosticity of the portal is crucial

What is the correct form to express the agnostic quality of something. The usual suffix -ness seems incorrect to me but I could not find a trustworthy reference to either confirm or deny this.

The only derived form I have encountered is the noun agnosticism

To describe my desired use case in an example:

This system comprises a portal and a service
The portal needs to be fully agnostic of the service
The agnosticness/agnosticity of the portal is crucial

Edit: as @sojourner correctly deduced, I should have stated this more clearly, my example is indeed meant to be used in the field of computer science.

What is the correct form to express the agnostic quality of something. The usual suffix -ness seems incorrect to me but I could not find a trustworthy reference to either confirm or deny this.

The only derived form I have encountered is the noun agnosticism

What is the correct form to express the agnostic quality of something. The usual suffix -ness seems incorrect to me but I could not find a trustworthy reference to either confirm or deny this.

The only derived form I have encountered is the noun agnosticism

To describe my desired use case in an example:

This system is comprised of a portal and a service
The portal needs to be fully agnostic of the service
The agnosticness/agnosticity of the portal is crucial