REST API filters - Any documentation?

Hello,

We’re beginning our journey using Portfolios’ Rest API.

While pretty straightforward in its use, there is one undocumented option that we are struggling with.

Using the Work endpoint API, the /public-api/v1/work query has a ‘filters’ parameter that does not have more extended syntax documentation than what we found on the Success Center

The single provided example for a work item (that is, a task below PPM) is: project.Id .eq 1906

This is a little odd because when looking at the project data type, there is no Id attribute, instead we’d usually use projet.structureCode or project.shortName

We tried applying a similar filter on those attributes but always got a HTTP 400 Bad Request response.

Is someone aware of a more detailed documentation on the API system used by Portfolios that would describe the filter syntax used here? Or is there a specific Portfolios API documentation available somewhere (maybe from the inner circle group)?

Thanks in advance and have a nice end of week.