`Arguments` type is too much strict

[jcooky]

I believe that for smoother MCP calls, we should change the type of Params.Arguments to interface{}.

Currently, Params.Arguments in mcp.CallToolRequest is defined as a map type, which I assume was intended to let MCP server developers own the argument type. However, using a map is too restrictive.

I propose changing it to any (or interface{}). Although this type is less strict, it would make it easier to convert the struct to JSON using reflection.

[0xNF]

I agree. Currently I have to do a lot of manual parsing over the arguments that would otherwise by solved by being able to use the standard json deserializers.

[douglarek]

second this. Parsing the fields in mcp.CallToolRequest each time is a nightmare, and there is an urgent need for some helper functions such as requireInt, requireStringArray, etc.

Furthermore, the CallToolRequest struct can have a Bind(any) method to directly support parsing into a struct for field validation.

[Crayzero]

And the tag of Arguments shoud be omitzero. Otherwise the marshalled json would never have "arguments":{}。

[jcooky]

Alternatively, the arguments can be of type json.RawMessage. Because this type already supports Marshal and Unmarshal, developers can easily convert the message into any other struct they need.

But, I found #116
I think It's correct for this issue.

[douglarek]

Let's look forward to the official implementation of mcp by golang/tools, and let this library rest in peace.

[emicklei]

Let's look forward to the official implementation of mcp by golang/tools, and let this library rest in peace.

Although I also wish to have first citizen support of MCP in the Go SDK, thanks to this mark3labs pkg, the Go community can already join the AI/agent rush by building robust, fast and less-resource-hungry MCP servers.

[rwjblue-glean]

FWIW, I think if someone has a good idea of what should be changed here it might be easier to discuss in a PR.

[pottekkat]

@jcooky @0xNF would using any for Params.Arguments and then just adding something like BindArguments method to marshal the arguments to a struct work? Do we still need helper functions if we do this, or should we always expect to have a struct to capture the arguments?

[pottekkat]

@jcooky @0xNF and others, #287 fixes the issue. It changes the type of arguments to any and it adds helper functions to unmarshal it to a struct and getting other values. Could you check and see if this matches your expectations?