MCP Server nullable params error

[TkachenkoAV]

My MCP server has function with nullable parameter - "salary":{"description":"New salary (optional).","type":["number","null"]

When I try to run ChatMessage, i get an error:
System.Text.Json.JsonException: 'The JSON value could not be converted to System.String. Path: $.properties.salary.type | LineNumber: 0 | BytePositionInLine: 560.'

InvalidOperationException: Cannot get the value of a token type 'StartArray' as a string