Tasks: Durable, Async Tool Calls

The last primitive is the newest, and the only one the spec still marks experimental. Tasks, added in 2025-11-25 , turn a request into call-now-fetch-later: instead of blocking until the work is done, the receiver returns a handle immediately, the requestor polls for status, and the real result is fetched later. The Go SDK does not implement tasks yet, so this post reads the spec&rsquo;s wire…