Include resource links in sampling spec

Author: LucaButBoring

docs/legacy/concepts/sampling.mdx

@@ -33,7 +33,7 @@ Sampling requests use a standardized message format:
     {
       role: "user" | "assistant",
       content: {
-        type: "text" | "image" | "audio" | "resource",
+        type: "text" | "image" | "audio" | "resource" | "resource_link",
 
         // For text:
         text?: string,
@@ -80,6 +80,7 @@ The `messages` array contains the conversation history to send to the LLM. Each
   - Text content with a `text` field
   - Image/audio content with `data` (base64) and `mimeType` fields
   - An embedded [resource](/docs/concepts/resources)
+  - A [resource](/docs/concepts/resources) link
 
 ### Model preferences
 

docs/specification/draft/client/sampling.mdx

@@ -167,18 +167,38 @@ Sampling messages can contain:
 }
 ```
 
+#### Resource Links
+
+A tool **MAY** return links to [Resources](/specification/draft/server/resources), to provide additional context
+or data. In this case, the tool will return a URI that can be subscribed to or fetched by the client:
+
+```json
+{
+  "type": "resource_link",
+  "uri": "file:///project/src/main.rs",
+  "name": "main.rs",
+  "description": "Primary application entry point",
+  "mimeType": "text/x-rust"
+}
+```
+
+<Info>
+  Resource links returned by tools are not guaranteed to appear in the results
+  of a `resources/list` request.
+</Info>
+
 #### Embedded Resources
 
-[Resources](/specification/draft/server/resources) **MAY** be embedded, to provide additional context
-or data, behind a URI that can be subscribed to or fetched again by the client later:
+[Resources](/specification/draft/server/resources) **MAY** be embedded to provide additional context
+or data using a suitable [URI scheme](./resources#common-uri-schemes). Servers that use embedded resources **SHOULD** implement the `resources` capability:
 
 ```json
 {
   "type": "resource",
   "resource": {
-    "uri": "resource://example",
-    "mimeType": "text/plain",
-    "text": "Resource content"
+    "uri": "file:///project/src/main.rs",
+    "mimeType": "text/x-rust",
+    "text": "fn main() {\n    println!(\"Hello world!\");\n}"
   }
 }
 ```