Add ILL Policy value to z39.50 response

[dlrueda]

Now that we're setting the ILL Policy to "Will not lend" for reserves materials (instead of adding a 919), so that BorrowDirect will exclude them, ILL needs to be able to see that data when in ILLiad so they know when to not lend materials.

They would like the ILL Policy value added to the z39.50 response, since this is what they use in ILLiad to check holdings.

Hilary said that in the z39.50 documentation, currently the 952$r is for "number of renewals".... so maybe we should choose a different field for ILL Policy. Is there a "lending policy" subfield for z39.50 response?

[jgreben]

Looking into this I am not sure if it will be possible (or easily accomplished) because the z39.50 module fetches and returns only the marc data, and the mappings can specify graphql fields to query to retrieve a record, but it only maps selected data from the holdings into the data returned. See also the inventory-fields-used Holdings level section

[dlrueda]

Sent a slack to Charlotte Whitt, PO for z39.50.

Background:
We are in the Borrow Direct consortium for resource sharing, using ReShare.  Mostly we use locations and material types to restrict lending, but we also restrict materials that otherwise would lend if they have been used for course reserves in the last two years.  Before FOLIO, we had this information in the 919 of the marc record.  But we saw in FOLIO that there is an ILL policy field in the holdings record, which seems perfect for this!  After talking about it at the Implementation SIG and the RA SIG, we saw no issues with this and are starting to use it, setting it to "Will not lend" when on reserve, with the intent to remove it after 2 years pass.
However, our resource sharing staff also use ILLiad to lend materials to libraries outside of Borrow Direct.  ILLiad uses z39.50 to look up the FOLIO holdings, which currently does not include the ILL policy field in the response.  This makes the ILLiad lookup imperfect, and staff need to go into FOLIO, or our discovery environment, to check the holdings ILL policy field.  This doubles the time for staff!
The ILL policy was added to OAI-PMH in Quesnelia for use with Interlibrary loan software, see [MODOAIPMH-523](https://folio-org.atlassian.net/browse/MODOAIPMH-523).  It seems appropriate to also add it to the z39.50 response, for the same reason.
Let me know what I can do to advance this.  I'm not sure if there is a SIG that it would be appropriate to discuss this, aside from perhaps the Implementation SIG.
Thank you for your help!!```