Add OutputSchema to Tool and CallToolResult.structuredContent

[pantanurag555]

OutputSchema was added to Tool after updates to the specification: modelcontextprotocol/modelcontextprotocol@c2e0fd6

I am working on changes to add it to the java-sdk. Creating an issue to avoid duplicated work.

[pantanurag555]

@tzolov @chemicL Hey there, I am picking up work on these changes and wanted to clarify the scope of the work based on the contributing guidelines.

Relevant PRs for python-sdk: #685 #684

Scope:

• Schema changes to add Tool.outputSchema and CallToolResult.structuredContent
• No server side changes since the tool definition and result definition are dependent on the server owner.
• Client side changes to create a caching mechanism of sorts for the tool list and leveraging this mechanism to validate the Tool.outputSchema against the CallToolResult.structuredContent when required [According to the spec: Clients SHOULD validate structured results against this schema.]
• Relevant tests

My major question about the scope of work revolves around the client side changes. I saw that there was some discussion around a standalone schema validator in #271. Should I introduce the caching mechanism and validator changes in the first PR itself or should that be a PR of its own? I think they can be separated for the first iteration since this is a SHOULD statement. Would like some maintainer input on this to reduce churn.

[loong-coder]

Hello @pantanurag555 , could you please provide an update on the #285 ? I'd appreciate knowing its current status.

[pantanurag555]

Hey @loong-coder. I have the changes but based on the contributing guidelines and comments from a maintainer in #271, I need to clarify the scope of work after creating an issue to claim work on the feature. I have tried to that in the comment above yours. If I don't hear back from them in a couple of days, I will raise the PR as is.