Is the choice of JsonIgnoreCondition.WhenWritingNull intentional?

[glen-84]

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Question Category

• Protocol Specification
• SDK Usage
• Server Implementation
• General Implementation
• Documentation
• Other

Your Question

var result = await mcpClient.CallToolAsync(
    "ExampleTool",
    new Dictionary<string, object?>
    {
        {
            "arg",
            new { field1A = new { field1B = new[] { new { field1C = (string?)null } } } }
        }
    });

I was surprised that field1C was dropped because it has a null value – is the use of JsonIgnoreCondition.WhenWritingNull intentional?

(I know that I can specify the JsonSerializerOptions – I'm just wondering why this is the default.)

[eiriktsarpalis]

We've adopted it as a default in the core protocol we found it beneficial to not transmit null properties. As you said, you can override this behavior for your own tool models.