S3 Annotations: Three Practical Use Cases in Agent Scenarios (opens in new tab)

S3 objects have historically carried three types of native metadata: system-defined metadata, user-defined metadata (2 KB, immutable after upload), and object tags. With Amazon S3 Metadata — a separate bucket-level feature — you can aggregate all metadata types into managed Iceberg tables for SQL-based querying. In June 2026, AWS introduced another metadata type: S3 Annotations — mutable, structured payloads (up to 1,000 per object, each up to 1 MB, totaling 1 GB) in JSON, XML, YAML, or plain...