Reauthorize tools changed by intervening call-tool filters

[PranavSenthilnathan]

Summary

Track a follow-up identified by @halter73 during review of #1722.

Repeated AddAuthorizationFilters() registrations are intended to protect tools when an intervening ordinary call-tool filter changes RequestContext.MatchedPrimitive. The current post-configuration approach installs only one alternate authorization filter because TryAddEnumerable deduplicates the post-configurer. As a result, a primitive changed later in the ordinary filter pipeline is not reauthorized.

Proposed behavior

• Keep one alternate authorization check outside Tasks so unauthorized task-backed calls are rejected before task creation.
• Add an ordinary authorization filter for each AddAuthorizationFilters() registration so callers can reauthorize after filters that replace the matched primitive.
• Consider caching the last authorized primitive in RequestContext.Items to avoid duplicate policy evaluation when the primitive has not changed.
• Add regression coverage with two authorization registrations separated by an ordinary filter that changes the matched tool.

Context

Original finding by @halter73: #1722 (comment)

Note

This issue was drafted with GitHub Copilot.