Check which organization and AI system are covered, the applicable standard version, the assessment dates, and the certificate's current status. Ask for enough supporting information to understand the evaluation and any relevant limitations. AIUC's published overview describes annual renewal and ongoing technical testing at least quarterly; verify what applies to the vendor's actual certification. Then compare the assessed use with the way your organization plans to use the product. A current certificate can inform vendor review, but it does not remove your responsibility to configure access, handle data appropriately, and monitor the service in your environment.
Related: SOC 2 audit and compliance hub.
Further reading: AIUC-1 certificate overview.