SEP-2322: Multi Round-Trip Requests

docs/docs.json

@@ -324,7 +324,8 @@
                       "specification/draft/basic/utilities/cancellation",
                       "specification/draft/basic/utilities/ping",
                       "specification/draft/basic/utilities/progress",
-                      "specification/draft/basic/utilities/tasks"
+                      "specification/draft/basic/utilities/tasks",
+                      "specification/draft/basic/utilities/mrtr"
                     ]
                   }
                 ]
@@ -428,6 +429,12 @@
               "seps/2207-oidc-refresh-token-guidance",
               "seps/2260-Require-Server-requests-to-be-associated-with-Client-requests"
             ]
+          },
+          {
+            "group": "Approved",
+            "pages": [
+              "seps/2322-MRTR"
+            ]
           }
         ]
       },

docs/specification/draft/basic/index.mdx

@@ -62,13 +62,25 @@ Responses are sent in reply to requests, containing either the result or error o
   id: string | number;
   result: {
     [key: string]: unknown;
-  }
+  };
+  resultType: string;
 }
 ```
 
 - Result responses **MUST** include the same ID as the request they correspond to.
 - Result responses **MUST** include a `result` field.
 - The `result` **MAY** follow any JSON object structure.
+- The `resultType` field **MUST** be included to indicate the type of the result. If no `resultType` is specified, "complete" should be assumed.
+
+##### ResultType
+
+The `resultType` field in a result response indicates the type of the result being returned. MCP supports poly-morphic result types,
+allowing servers to return different structures based on the outcome of the request. The `resultType` field is a string that clients
+can use to determine how to parse and handle the `result` object.
+
+- A `resultType` of `"complete"` the request completed successfully and the result contains the final content.
+- A `resultType` of `"input_required"` the request is incomplete and more information is needed to process the request. The result contains an `InputRequiredResult` object with additional information needed.
+- If `resultType` is not specified, clients **MUST** assume a default value of `"complete"` for backwards compatibility.
 
 #### Error Responses
 

docs/specification/draft/basic/transports.mdx

@@ -62,7 +62,7 @@ guide below.
 
 In the **Streamable HTTP** transport, the server operates as an independent process that
 can handle multiple client connections. This transport uses HTTP POST and GET requests.
-Server can optionally make use of
+The server can optionally make use of
 [Server-Sent Events](https://en.wikipedia.org/wiki/Server-sent_events) (SSE) to stream
 multiple server messages. This permits basic MCP servers, as well as more feature-rich
 servers supporting streaming and server-to-client notifications and requests.
@@ -556,7 +556,7 @@ When constructing a `tools/call` request via HTTP transport, the client **MUST**
 
 Intermediate servers that do not recognize an `Mcp-Param-{Name}` header **MUST** forward it and otherwise ignore it, as required by the [HTTP Semantics RFC](https://www.rfc-editor.org/rfc/rfc9110.html#name-field-names).
 
-Servers **MUST** reject requests with a recognized `Mcp-Param-{Name}` headers that contain invalid
+Servers **MUST** reject requests with a recognized `Mcp-Param-{Name}` header that contains invalid
 characters (see [Value Encoding](#value-encoding)).
 
 Any server that processes the message body **MUST** validate that encoded header values,
@@ -603,7 +603,7 @@ protocol version 2024-11-05) as follows:
    - If it succeeds, the client can assume this is a server supporting the new Streamable
      HTTP transport.
    - If it fails with the following HTTP status codes "400 Bad Request", "404 Not
-     Found" or "405 Method Not Allowed":
+     Found", or "405 Method Not Allowed":
      - Issue a GET request to the server URL, expecting that this will open an SSE stream
        and return an `endpoint` event as the first event.
      - When the `endpoint` event arrives, the client can assume this is a server running