Add capabilities and annotations for tasks

Author: LucaButBoring

docs/specification/draft/basic/lifecycle.mdx

@@ -64,7 +64,23 @@ The client **MUST** initiate this phase by sending an `initialize` request conta
         "listChanged": true
       },
       "sampling": {},
-      "elicitation": {}
+      "elicitation": {},
+      "tasks": {
+        "sampling": {
+          "createMessage": true
+        },
+        "elicitation": {
+          "create": true
+        },
+        "roots": {
+          "list": true
+        },
+        "tasks": {
+          "get": true,
+          "list": true,
+          "result": true
+        }
+      }
     },
     "clientInfo": {
       "name": "ExampleClient",
@@ -102,6 +118,25 @@ The server **MUST** respond with its own capabilities and information:
       },
       "tools": {
         "listChanged": true
+      },
+      "tasks": {
+        "tools": {
+          "call": true,
+          "list": true
+        },
+        "resources": {
+          "read": true,
+          "list": true
+        },
+        "prompts": {
+          "get": true,
+          "list": true
+        },
+        "tasks": {
+          "get": true,
+          "list": true,
+          "result": true
+        }
       }
     },
     "serverInfo": {
@@ -171,12 +206,14 @@ Key capabilities include:
 | Client   | `roots`        | Ability to provide filesystem [roots](/specification/draft/client/roots)             |
 | Client   | `sampling`     | Support for LLM [sampling](/specification/draft/client/sampling) requests            |
 | Client   | `elicitation`  | Support for server [elicitation](/specification/draft/client/elicitation) requests   |
+| Client   | `tasks`        | Support for [task-augmented](/specification/draft/basic/utilities/tasks) client requests |
 | Client   | `experimental` | Describes support for non-standard experimental features                             |
 | Server   | `prompts`      | Offers [prompt templates](/specification/draft/server/prompts)                       |
 | Server   | `resources`    | Provides readable [resources](/specification/draft/server/resources)                 |
 | Server   | `tools`        | Exposes callable [tools](/specification/draft/server/tools)                          |
 | Server   | `logging`      | Emits structured [log messages](/specification/draft/server/utilities/logging)       |
 | Server   | `completions`  | Supports argument [autocompletion](/specification/draft/server/utilities/completion) |
+| Server   | `tasks`        | Support for [task-augmented](/specification/draft/basic/utilities/tasks) server requests |
 | Server   | `experimental` | Describes support for non-standard experimental features                             |
 
 Capability objects can describe sub-capabilities like:

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

@@ -16,7 +16,76 @@ Implementations are free to expose tasks through any interface pattern that suit
 
 ## Capabilities
 
-Unlike other protocol features, tasks _do not_ require capabilities to be declared.
+Servers and clients that support task-augmented requests **MUST** declare a `tasks` capability during initialization. The `tasks` capability is structured by request category, with boolean properties indicating which specific request types support task augmentation.
+
+### Server Capabilities
+
+Servers declare which server-side requests can be augmented with tasks:
+
+```json
+{
+  "capabilities": {
+    "tasks": {
+      "tools": {
+        "call": true,
+        "list": true
+      },
+      "resources": {
+        "read": true,
+        "list": true
+      },
+      "prompts": {
+        "get": true,
+        "list": true
+      },
+      "tasks": {
+        "get": true,
+        "list": true,
+        "result": true
+      }
+    }
+  }
+}
+```
+
+Servers **MAY** support tasks for any subset of their available request types. If a request type is not listed in the `tasks` capability or is set to `false`, requestors **SHOULD NOT** augment those requests with task metadata.
+
+The `tasks.tasks` nested capability indicates whether the task management operations themselves (`tasks/get`, `tasks/list`, `tasks/result`) can be augmented with tasks, enabling recursive task tracking for task queries.
+
+### Client Capabilities
+
+Clients declare which client-side requests can be augmented with tasks:
+
+```json
+{
+  "capabilities": {
+    "tasks": {
+      "sampling": {
+        "createMessage": true
+      },
+      "elicitation": {
+        "create": true
+      },
+      "roots": {
+        "list": true
+      },
+      "tasks": {
+        "get": true,
+        "list": true,
+        "result": true
+      }
+    }
+  }
+}
+```
+
+The `tasks.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).
+
+### 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.tools.call: true`, then clients may augment `tools/call` requests with task metadata. However, if the server does not declare `tasks.resources.read`, clients should not send task-augmented `resources/read` requests.
 
 ## Protocol Messages