modelcontextprotocol · pantanurag555 · May 8, 2025 · May 9, 2025 · May 28, 2025 · May 30, 2025
@@ -37,6 +37,9 @@ Each tool is defined with the following structure:
     destructiveHint?: boolean; // If true, the tool may perform destructive updates
     idempotentHint?: boolean;  // If true, repeated calls with same args have no additional effect
     openWorldHint?: boolean;   // If true, tool interacts with external entities
+    statelessHint?: boolean;   // If true, tool does not maintain state from previous requests
+    streamingHint?: boolean;   // If true, tool streams its responses
+    asyncHint?: boolean;       // If true, tool works asynchronously to generate responses
   }
 }
 ```
@@ -333,6 +336,9 @@ The MCP specification defines the following annotations for tools:
 | `destructiveHint` | boolean | true | If true, the tool may perform destructive updates (only meaningful when `readOnlyHint` is false) |
 | `idempotentHint` | boolean | false | If true, calling the tool repeatedly with the same arguments has no additional effect (only meaningful when `readOnlyHint` is false) |
 | `openWorldHint` | boolean | true | If true, the tool may interact with an "open world" of external entities |
+| `statelessHint` | boolean | false | If true, this tool does not maintain state based on previous requests |
+| `streamingHint` | boolean | false | If true, this tool may stream its responses |
+| `asyncHint` | boolean | false | If true, this tool accepts a request and continues to work asynchronously to generate responses |
 
 ### Example usage
 
@@ -353,7 +359,9 @@ Here's how to define tools with annotations for different scenarios:
   annotations: {
     title: "Web Search",
     readOnlyHint: true,
-    openWorldHint: true
+    openWorldHint: true,
+    streamingHint: false,
+    asyncHint: false
   }
 }
 
@@ -373,7 +381,9 @@ Here's how to define tools with annotations for different scenarios:
     readOnlyHint: false,
     destructiveHint: true,
     idempotentHint: true,
-    openWorldHint: false
+    openWorldHint: false,
+    statelessHint: true,
+    streamingHint: false,
   }
 }
 
@@ -394,7 +404,32 @@ Here's how to define tools with annotations for different scenarios:
     readOnlyHint: false,
     destructiveHint: false,
     idempotentHint: false,
-    openWorldHint: false
+    openWorldHint: false,
+    statelessHint: true,
+  }
+}
+
+// An asynchronous timeseries forecasting tool
+{
+  name: "create_timeseries_forecast",
+  description: "Create a forecast for timeseries data",
+  inputSchema: {
+    type: "object",
+    properties: {
+      timeseries: { type: "object" },
+      forecast_horizon: { type: "number" }
+    },
+    required: ["timeseries", "forecast_horizon"]
+  },
+  annotations: {
+    title: "Create Timeseries Forecast",
+    readOnlyHint: false,
+    destructiveHint: false,
+    idempotentHint: true,
+    openWorldHint: false,
+    statelessHint: true,
+    streamingHint: false,
+    asyncHint: true,
   }
 }
 ```

@@ -2315,6 +2315,10 @@
         "ToolAnnotations": {
             "description": "Additional properties describing a Tool to clients.\n\nNOTE: all properties in ToolAnnotations are **hints**.\nThey are not guaranteed to provide a faithful description of\ntool behavior (including descriptive properties like `title`).\n\nClients should never make tool use decisions based on ToolAnnotations\nreceived from untrusted servers.",
             "properties": {
+                "asyncHint": {
+                    "description": "If true, this tool accepts a request and continues to work\nasynchronously to generate responses.\n\nDefault: false",
+                    "type": "boolean"
+                },
                 "destructiveHint": {
                     "description": "If true, the tool may perform destructive updates to its environment.\nIf false, the tool performs only additive updates.\n\n(This property is meaningful only when `readOnlyHint == false`)\n\nDefault: true",
                     "type": "boolean"
@@ -2331,6 +2335,14 @@
                     "description": "If true, the tool does not modify its environment.\n\nDefault: false",
                     "type": "boolean"
                 },
+                "statelessHint": {
+                    "description": "If true, this tool does not maintain state based on previous requests.\nIf false, the tool may maintain state based on previous interactions\nand the context from the previous requests might influence the next\nresponse.\n\nDefault: false",
+                    "type": "boolean"
+                },
+                "streamingHint": {
+                    "description": "If true, this tool streams its responses.\n\nDefault: false",
+                    "type": "boolean"
+                },
                 "title": {
                     "description": "A human-readable title for the tool.",
                     "type": "string"

@@ -788,6 +788,31 @@ export interface ToolAnnotations {
    * Default: true
    */
   openWorldHint?: boolean;
+
+  /**
+   * If true, this tool does not maintain state based on previous requests.
+   * If false, the tool may maintain state based on previous interactions
+   * and the context from the previous requests might influence the next
+   * response.
+   *
+   * Default: false
+   */
+  statelessHint?: boolean;
+
+  /**
+   * If true, this tool streams its responses.
+   *
+   * Default: false
+   */
+  streamingHint?: boolean;
+
+  /**
+   * If true, this tool accepts a request and continues to work
+   * asynchronously to generate responses.
+   *
+   * Default: false
+   */
+  asyncHint?: boolean;
 }
 
 /**