Enable FastMCP to filter tools, prompts, resources using a fine grained policy

Description

The authorization protocol allows MCP to implement course grained authorization checks e.g. a principal can/cannot access the server.

For advanced use cases though it is useful to be able to limit access on a per tool/resource/prompt basis.

There are a range of authorization tools that can be used however rather than being specific I suggest it is better to provide a plugin API that allows providers to pick their underlying authorization approach.

I have a patch that shows this idea, I'll open a draft pull request to illustrate the idea and allow for further testing & refinement.

References

No response

まず、きめ細かな認可の提案と issue で言及されているパッチを確認し、それを MCP 認可プロトコルと比較します。FastMCP が、ツール、プロンプト、リソースへのアクセスをそれぞれ独立して許可または拒否できる provider plugin API を公開し、テストを通じてアプローチが改良された時点で作業は完了です。