Claude docs changes for April 13th, 2026 [diff]

Executive Summary

• Files API requests within managed agent sessions now require the managed-agents-2026-04-01 beta header in addition to files-api-2025-04-14
• Session ID prefix in the managed agents Files API examples corrected from sess_ to sesn_

API changes

Changed documents

managed-agents/files [Source]

• Files API calls within managed agent sessions now require both managed-agents-2026-04-01 and files-api-2025-04-14 beta headers (previously only files-api-2025-04-14 was shown). [lines 110-116] [Source]
• Session ID example value corrected from sess_abc123 to sesn_abc123. [line 107] [Source]