modelcontextprotocol · justin-yi-wang · Mar 26, 2025 · Mar 26, 2025 · Mar 26, 2025 · Mar 26, 2025
diff --git a/schema/2025-03-26/schema.json b/schema/2025-03-26/schema.json
@@ -11,11 +11,34 @@
                     },
                     "type": "array"
                 },
+                "contentSource": {
+                    "description": "Attribution information for the content provider(s).\n\nIdentifies the original platform, service, or content creator. Multiple sources\nindicate aggregated or compiled content. Used for attribution, filtering, and\nhelping users identify trusted content origins.",
+                    "items": {
+                        "type": "string"
+                    },
+                    "type": "array"
+                },
+                "contentType": {
+                    "description": "Semantic category of the object.\n\nRepresents the nature of the content in a user-facing format. Should use simple, recognizable terms\nthat categorize the data for users (e.g., \"Webpage\", \"Song\", \"Article\", \"Image\", \"Document\").\nThis helps clients render appropriate UI treatments and helps users understand what kind of\ncontent they're interacting with.",
+                    "type": "string"
+                },
+                "displayTitle": {
+                    "description": "Primary display name for the content.\n\nUsed for UI headings, navigation elements, content identification, etc.\nShould be concise yet descriptive enough to distinguish this content\nfrom others (e.g., webpage title, document name, media title).",
+                    "type": "string"
+                },
+                "iconUrl": {
+                    "description": "A URL from which a client can fetch an icon to represent this object.",
+                    "type": "string"
+                },
                 "priority": {
                     "description": "Describes how important this data is for operating the server.\n\nA value of 1 means \"most important,\" and indicates that the data is\neffectively required, while 0 means \"least important,\" and indicates that\nthe data is entirely optional.",
                     "maximum": 1,
                     "minimum": 0,
                     "type": "number"
+                },
+                "sourceUrl": {
+                    "description": "Direct link to access the original content.\n\nAllows users to navigate to the source material in its native context.\nMay require authentication if pointing to protected resources.",
+                    "type": "string"
                 }
             },
             "type": "object"
@@ -638,6 +661,10 @@
                     "description": "This result property is reserved by the protocol to allow clients and servers to attach additional metadata to their responses.",
                     "type": "object"
                 },
+                "annotations": {
+                    "$ref": "#/definitions/ServerAnnotations",
+                    "description": "Optional annotations for the client."
+                },
                 "capabilities": {
                     "$ref": "#/definitions/ServerCapabilities"
                 },
@@ -1771,6 +1798,19 @@
             ],
             "type": "object"
         },
+        "ServerAnnotations": {
+            "properties": {
+                "iconUrl": {
+                    "description": "A URL from which a client can fetch an icon to represent the server.",
+                    "type": "string"
+                },
+                "serverName": {
+                    "description": "Identifier for the server instance or service.\n\nHuman-readable name used for server identification. Should be concise yet distinctive enough to identify \nthis specific server among multiple instances.",
+                    "type": "string"
+                }
+            },
+            "type": "object"
+        },
         "ServerCapabilities": {
             "description": "Capabilities that a server may support. Known capabilities are defined here, in this schema, but this is not a closed set: any server can define its own, additional capabilities.",
             "properties": {

diff --git a/schema/2025-03-26/schema.ts b/schema/2025-03-26/schema.ts
@@ -173,6 +173,22 @@ export interface InitializeRequest extends Request {
   };
 }
 
+
+export interface ServerAnnotations {
+  /**
+   * Identifier for the server instance or service.
+   * 
+   * Human-readable name used for server identification. Should be concise yet distinctive enough to identify 
+   * this specific server among multiple instances.
+   */
+  serverName?: string;
+
+  /**
+   * A URL from which a client can fetch an icon to represent the server.
+   */
+  iconUrl?: string;
+}
+
 /**
  * After receiving an initialize request from the client, the server sends this response.
  */
@@ -190,6 +206,11 @@ export interface InitializeResult extends Result {
    * This can be used by clients to improve the LLM's understanding of available tools, resources, etc. It can be thought of like a "hint" to the model. For example, this information MAY be added to the system prompt.
    */
   instructions?: string;
+
+  /**
+   * Optional annotations for the client.
+   */
+  annotations?: ServerAnnotations;
 }
 
 /**
@@ -934,6 +955,47 @@ export interface Annotations {
    * @maximum 1
    */
   priority?: number;
+
+  /**
+   * Primary display name for the content.
+   * 
+   * Used for UI headings, navigation elements, content identification, etc.
+   * Should be concise yet descriptive enough to distinguish this content
+   * from others (e.g., webpage title, document name, media title).
+   */
+  displayTitle?: string;
+
+  /**
+   * A URL from which a client can fetch an icon to represent this object.
+   */
+  iconUrl?: string;
+
+  /**
+   * Attribution information for the content provider(s).
+   * 
+   * Identifies the original platform, service, or content creator. Multiple sources
+   * indicate aggregated or compiled content. Used for attribution, filtering, and
+   * helping users identify trusted content origins.
+   */
+  contentSource?: string[];
+
+  /**
+   * Semantic category of the object.
+   * 
+   * Represents the nature of the content in a user-facing format. Should use simple, recognizable terms
+   * that categorize the data for users (e.g., "Webpage", "Song", "Article", "Image", "Document").
+   * This helps clients render appropriate UI treatments and helps users understand what kind of
+   * content they're interacting with.
+   */
+  contentType?: string;
+
+  /**
+   * Direct link to access the original content.
+   *
+   * Allows users to navigate to the source material in its native context.
+   * May require authentication if pointing to protected resources.   
+   */
+  sourceUrl?: string;
 }
 
 /**