OCLC defines cataloging "etiquette" for WorldCat records in their Bibliographic Formats and Standards guide, specifically the Quality Assurance section.
WMS Record Manager users with Cataloging Full or Admin roles should follow the General Guidelines in Section 5.2.1.
Section 5.2.3 - Editing capabilities for PCC records outlines the fields non-PCC catalogers can edit on BIBCO (PCC) records (identified by MARC 042). While not enforced by Record Manager, these guidelines provide best practices for shared bibliographic data.
If you're unsure about an edit, submit a bib file maintenance request to OCLC Metadata Quality staff at bibchange@oclc.org.
A guide to help fix the most common data migration errors,
To add an item quickly and painlessly you can use the Acquisitions workflow.