Regression from 0.16.8 to 0.17 regarding default null values in tools

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When trying to execute a MCP tool using MCP Inspector version 0.17, if the tool has a parameter with null default value, then default HTML input is empty (as before), but when executing there is an error on Chrome/Safari.

On Safari it looks like this:

I tested on Chrome as well, the bug appears too (I am running macOS).

If I manually set the field to null, then it works. On MCP Inspector 0.16, those default values were handled automatically.
If you have a tool with lots of default null values, filling everything manually can quite quite long.

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For the record, this is still present in 0.17.1.

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@cliffhall I cannot re-open the issue, but I still see this in 0.17.2.
Note that in the examples I have, the parameters are defined as pax_ages: list[int] | None = Field(...)

[cliffhall]

@cliffhall I cannot re-open the issue, but I still see this in 0.17.2. Note that in the examples I have, the parameters are defined as pax_ages: list[int] | None = Field(...)

I can't tell what language you're using there, I'm assuming Python. But the key is how it renders as a JSON schema. Could you paste a screenshot of the tools/list response with the tool's inputSchema opened to show the field(s) you're having a problem with?

Example

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Of course, here it is:

And here is what the error looks like: