API – purchase record project tags

Feature requested
I would like to be able to add project tags to purchase records created via API, and to search for purchase records using tags.

Typical use case
I use tags to separate out different long-lived projects by client to manage P&L. I want to use automation to process structured messages from suppliers to automatically create the purchase records and corresponding invoices. To do this I need my tool to be able to tag the purchase record appropriately, otherwise there will still be manual work involved in setting up the purchases, which somewhat defeats the purpose of writing automation for this.

How I would expect it to work
Similar to the invoices API calls – I can provide up to five ProjectTags values in the call to Purchase_Create and in the corresponding Search interface too to find pre-existing purchase records.