Tool filter method

[Kyu]

Is your feature request related to a problem? Please describe.
This feature is related to the use case where one only needs access to certain tools in a mcp session.
Related issue where me and a mcp author discuss: kooshi/SharpToolsMCP#13 (comment)

Describe the solution you'd like
Would like the WithToolsFromAssembly signature/impl to look like

public static IMcpServerBuilder WithToolsFromAssembly(
this IMcpServerBuilder builder,
Assembly? toolAssembly = null,
JsonSerializerOptions? serializerOptions = null,
SomeFilterObject? filter = null)

Describe alternatives you've considered
We could just filter manually, but we figured it might be a useful feature for all

[stephentoub]

Note that WithToolsFromAssembly is just:

builder.WithTools(
    toolAssembly.GetTypes().Where(t => t.GetCustomAttribute<McpServerToolTypeAttribute>() != null),
    serializerOptions);

If you want to filter it, you can do the same thing with whatever additional filters you want.

[Kyu]

Yeah, we were going to go that route, but we thought that having it built in as a general api might be useful for all

[eiriktsarpalis]

What shape would you expect the filtering object to have? Func<Type, bool> presumably?

[Kyu]

@eiriktsarpalis yes, exactly. That way a you can pass the assemblies to the filter

[Kyu]

I'm willing to make the PR, just wanted to discuss first

[eiriktsarpalis]

I agree with @stephentoub that this doesn't seem to provide a lot of value, and can be implemented trivially as an extension. Similar to the existing WithToolsFromAssembly method, it cannot be made to work with trimmed apps/Native AOT so from my perspective that's another point against shipping it out of the box.