“The OCLC Research linked data Wikibase prototype (“Project Passage”) provided a sandbox in which librarians from 16 US institutions could experiment with creating linked data to describe resources—without requiring knowledge of the technical machinery of linked data. This report provides an overview of the context in which the prototype was developed, how the Wikibase platform was adapted for use by librarians, and eight use cases where pilot participants (co-authors of this report) describe their experience of creating metadata for resources in various formats and languages using the Wikibase editing interface. During the ten months of the pilot, the participants gained insight in both the potential of linked data in library cataloging workflows and the gaps that must be addressed before machine-readable semantic data can be fully adopted. Among the lessons learned:

• The building blocks of Wikibase can be used to create structured data with a precision that exceeds current library standards.
• The Wikibase platform enables user-driven ontology design but raises concerns about how to manage and maintain ontologies.
• The Wikibase platform, supplemented with OCLC’s enhancements and stand-alone utilities, enables librarians to see the results of their effort in a discovery interface without leaving the metadata-creation workflow.
• Robust tools are required for local data management.
• To populate knowledge graphs with library metadata, tools that facilitate the import and enhancement of data created elsewhere are recommended.
• The pilot underscored the need for interoperability between data sources, both for ingest and export.
• The traditional distinction between authority and bibliographic data disappears in a Wikibase description…”