Restrict tasks to tools/call, elicitation/create, and sampling/createMessage

Author: LucaButBoring

docs/specification/draft/basic/utilities/tasks.mdx

@@ -28,32 +28,15 @@ Servers declare which server-side requests can be augmented with tasks:
     "tasks": {
       "requests": {
         "tools": {
-          "call": true,
-          "list": true
-        },
-        "resources": {
-          "read": true,
-          "list": true
-        },
-        "prompts": {
-          "get": true,
-          "list": true
-        },
-        "tasks": {
-          "get": true,
-          "list": true,
-          "result": true,
-          "delete": true
+          "call": true
         }
       }
     }
   }
 }
 ```
 
-Servers **MAY** support tasks for any subset of their available request types. If a request type is not listed in the `tasks.requests` capability or is set to `false`, requestors **SHOULD NOT** augment those requests with task metadata.
-
-The `tasks.requests.tasks` nested capability indicates whether the task management operations themselves (`tasks/get`, `tasks/list`, `tasks/result`, `tasks/delete`) can be augmented with tasks, enabling recursive task tracking for task queries.
+This set of capabilities is exhaustive. If a request type is not present, it does not support task-augmentation.
 
 ### Client Capabilities
 
@@ -69,29 +52,26 @@ Clients declare which client-side requests can be augmented with tasks:
         },
         "elicitation": {
           "create": true
-        },
-        "roots": {
-          "list": true
-        },
-        "tasks": {
-          "get": true,
-          "list": true,
-          "result": true,
-          "delete": true
         }
       }
     }
   }
 }
 ```
 
-The `tasks.requests.tasks` capability applies when the client is acting as a receiver of task-augmented requests from the server (for example, when a server sends a task-augmented `sampling/createMessage` request to the client).
+This set of capabilities is exhaustive. If a request type is not present, it does not support task-augmentation.
 
 ### Capability Negotiation
 
 During the initialization phase, both parties exchange their `tasks` capabilities to establish which operations support task-based execution. Requestors **MUST** only augment requests with task metadata if the corresponding capability has been declared by the receiver.
 
-For example, if a server's capabilities include `tasks.requests.tools.call: true`, then clients may augment `tools/call` requests with task metadata. However, if the server does not declare `tasks.requests.resources.read`, clients should not send task-augmented `resources/read` requests.
+For example, if a server's capabilities include `tasks.requests.tools.call: true`, then clients may augment `tools/call` requests with task metadata. If a client's capabilities include `tasks.requests.sampling.createMessage: true`, then servers may augment `sampling/createMessage` requests with task metadata.
+
+### Tool-Level Negotiation
+
+Tool calls are given special consideration for the purpose of task augmentation. In the result of `tools/list`, tools declare support for tasks via `annotations.taskHint`.
+
+This is to be interpreted as a fine-grained layer in addition to capabilities. If a server's capabilities include `tasks.requests.tools.call: false`, then clients **MUST NOT** attempt to use task augmentation on that server's tools, even if they declare tool-level support via `annotations.taskHint`.
 
 ## Protocol Messages