When running the search or aggregation tool the following error happens on schema validation
`RuntimeError: Invalid structured content returned by tool search_messages: '2025-10-17T18:16:29.799Z' is not of type 'object'

Failed validating 'type' in schema['properties']['metadata']['properties']['effective_timerange']['allOf'][0]['properties']['to']:
{'type': 'object'}

On instance['metadata']['effective_timerange']['to']:
'2025-10-17T18:16:29.799Z'`

Steps to Reproduce (for bugs)

Graylog 7.0 Beta 4 - MCP Server
Strands Agent in Python

Agent prompt:"For the past 5 minutes what types of log messages have been received? "