diff --git a/packages/core/src/types/spec.types.ts b/packages/core/src/types/spec.types.ts
index a03f21f134..991e9b7904 100644
--- a/packages/core/src/types/spec.types.ts
+++ b/packages/core/src/types/spec.types.ts
@@ -3,7 +3,7 @@
  *
  * Source: https://github.com/modelcontextprotocol/modelcontextprotocol
  * Pulled from: https://raw.githubusercontent.com/modelcontextprotocol/modelcontextprotocol/main/schema/draft/schema.ts
- * Last updated from commit: 5c25208be86db5033f644a4e0d005e08f699ef3d
+ * Last updated from commit: e3f281c7243b7dfe4c0dca450230fe3d7de3cf8b
  *
  * DO NOT EDIT THIS FILE MANUALLY. Changes will be overwritten by automated updates.
  * To update this file, run: pnpm run fetch:spec-types
@@ -34,7 +34,7 @@ export type JSONArray = JSONValue[];
 export type JSONRPCMessage = JSONRPCRequest | JSONRPCNotification | JSONRPCResponse;
 
 /** @internal */
-export const LATEST_PROTOCOL_VERSION = 'DRAFT-2026-v1';
+export const LATEST_PROTOCOL_VERSION = '2026-07-28';
 /** @internal */
 export const JSONRPC_VERSION = '2.0';
 
@@ -48,7 +48,8 @@ export const JSONRPC_VERSION = '2.0';
  * **Prefix:**
  * - Optional — if specified, MUST be a series of _labels_ separated by dots (`.`), followed by a slash (`/`).
  * - Labels MUST start with a letter and end with a letter or digit. Interior characters may be letters, digits, or hyphens (`-`).
- * - Any prefix consisting of zero or more labels, followed by `modelcontextprotocol` or `mcp`, followed by any label, is **reserved** for MCP use. For example: `modelcontextprotocol.io/`, `mcp.dev/`, `api.modelcontextprotocol.org/`, and `tools.mcp.com/` are all reserved.
+ * - Implementations SHOULD use reverse DNS notation (e.g., `com.example/` rather than `example.com/`).
+ * - Any prefix where the second label is `modelcontextprotocol` or `mcp` is **reserved** for MCP use. For example: `io.modelcontextprotocol/`, `dev.mcp/`, `org.modelcontextprotocol.api/`, and `com.mcp.tools/` are all reserved. However, `com.example.mcp/` is NOT reserved, as the second label is `example`.
  *
  * **Name:**
  * - Unless empty, MUST start and end with an alphanumeric character (`[a-z0-9A-Z]`).
@@ -71,38 +72,80 @@ export interface RequestMetaObject extends MetaObject {
      * If specified, the caller is requesting out-of-band progress notifications for this request (as represented by {@link ProgressNotification | notifications/progress}). The value of this parameter is an opaque token that will be attached to any subsequent notifications. The receiver is not obligated to provide these notifications.
      */
     progressToken?: ProgressToken;
+    /**
+     * The MCP Protocol Version being used for this request. Required.
+     *
+     * For the HTTP transport, this value MUST match the `MCP-Protocol-Version`
+     * header; otherwise the server MUST return a `400 Bad Request`. If the
+     * server does not support the requested version, it MUST return an
+     * {@link UnsupportedProtocolVersionError}.
+     */
+    'io.modelcontextprotocol/protocolVersion': string;
+    /**
+     * Identifies the client software making the request. Required.
+     *
+     * The {@link Implementation} schema requires `name` and `version`; other
+     * fields are optional.
+     */
+    'io.modelcontextprotocol/clientInfo': Implementation;
+    /**
+     * The client's capabilities for this specific request. Required.
+     *
+     * Capabilities are declared per-request rather than once at initialization;
+     * an empty object means the client supports no optional capabilities.
+     * Servers MUST NOT infer capabilities from prior requests.
+     */
+    'io.modelcontextprotocol/clientCapabilities': ClientCapabilities;
+    /**
+     * The desired log level for this request. Optional.
+     *
+     * If absent, the server MUST NOT send any {@link LoggingMessageNotification | notifications/message}
+     * notifications for this request. The client opts in to log messages by
+     * explicitly setting a level. Replaces the former `logging/setLevel` RPC.
+     *
+     * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+     * Remains in the specification for at least twelve months; see the
+     * deprecated features registry.
+     */
+    'io.modelcontextprotocol/logLevel'?: LoggingLevel;
 }
 
 /**
- * A progress token, used to associate progress notifications with the original request.
+ * Extends {@link MetaObject} with additional notification-specific fields. All key naming rules from `MetaObject` apply.
  *
+ * @see {@link MetaObject} for key naming rules and reserved prefixes.
+ * @see [General fields: `_meta`](/specification/draft/basic/index#meta) for more details.
  * @category Common Types
  */
-export type ProgressToken = string | number;
+export interface NotificationMetaObject extends MetaObject {
+    /**
+     * Identifies the subscription stream a notification was delivered on. The
+     * server MUST include this key on every notification delivered via a
+     * {@link SubscriptionsListenRequest | subscriptions/listen} stream, so the
+     * client can correlate the notification with the originating subscription.
+     * The key is absent on notifications not delivered via a subscription
+     * stream (e.g. progress notifications for an in-flight request), which is
+     * why it is optional here.
+     *
+     * The value is the JSON-RPC ID of the `subscriptions/listen` request that
+     * opened the stream.
+     */
+    'io.modelcontextprotocol/subscriptionId'?: RequestId;
+}
 
 /**
- * An opaque token used to represent a cursor for pagination.
+ * A progress token, used to associate progress notifications with the original request.
  *
  * @category Common Types
  */
-export type Cursor = string;
+export type ProgressToken = string | number;
 
 /**
- * Common params for any task-augmented request.
+ * An opaque token used to represent a cursor for pagination.
  *
- * @internal
+ * @category Common Types
  */
-export interface TaskAugmentedRequestParams extends RequestParams {
-    /**
-     * If specified, the caller is requesting task-augmented execution for this request.
-     * The request will return a {@link CreateTaskResult} immediately, and the actual result can be
-     * retrieved later via {@link GetTaskPayloadRequest | tasks/result}.
-     *
-     * Task augmentation is subject to capability negotiation - receivers MUST declare support
-     * for task augmentation of specific request types in their capabilities.
-     */
-    task?: TaskMetadata;
-}
+export type Cursor = string;
 
 /**
  * Common params for any request.
@@ -110,7 +153,7 @@ export interface TaskAugmentedRequestParams extends RequestParams {
  * @category Common Types
  */
 export interface RequestParams {
-    _meta?: RequestMetaObject;
+    _meta: RequestMetaObject;
 }
 
 /** @internal */
@@ -127,7 +170,7 @@ export interface Request {
  * @category Common Types
  */
 export interface NotificationParams {
-    _meta?: MetaObject;
+    _meta?: NotificationMetaObject;
 }
 
 /** @internal */
@@ -138,6 +181,16 @@ export interface Notification {
     params?: { [key: string]: any };
 }
 
+/**
+ * Indicates the type of a {@link Result} object, allowing the client to
+ * determine how to parse the response.
+ *
+ * complete - the request completed successfully and the result contains the final content.
+ * input_required - the request requires additional input and the result contains an {@link InputRequiredResult} object with instructions for the client to provide additional input before retrying the original request.
+ * @category Common Types
+ */
+export type ResultType = 'complete' | 'input_required' | string;
+
 /**
  * Common result fields.
  *
@@ -145,6 +198,16 @@ export interface Notification {
  */
 export interface Result {
     _meta?: MetaObject;
+    /**
+     * Indicates the type of the result, which allows the client to determine
+     * how to parse the result object.
+     *
+     * Servers implementing this protocol version MUST include this field.
+     * For backward compatibility, when a client receives a result from a
+     * server implementing an earlier protocol version (which does not include
+     * `resultType`), the client MUST treat the absent field as `"complete"`.
+     */
+    resultType: ResultType;
     [key: string]: unknown;
 }
 
@@ -256,15 +319,14 @@ export interface InvalidRequestError extends Error {
 /**
  * A JSON-RPC error indicating that the requested method does not exist or is not available.
  *
- * In MCP, this error is returned when a request is made for a method that requires a capability that has not been declared. This can occur in either direction:
+ * In MCP, a server returns this error when a client invokes a method the server does not implement — either a genuinely unknown method, or one gated behind a server capability the server did not advertise (e.g., calling `prompts/list` when the `prompts` capability was not advertised).
  *
- * - A server returning this error when the client requests a capability it doesn't support (e.g., requesting completions when the `completions` capability was not advertised)
- * - A client returning this error when the server requests a capability it doesn't support (e.g., requesting roots when the client did not declare the `roots` capability)
+ * A request that requires a client capability the client did not declare is signalled instead by {@link MissingRequiredClientCapabilityError} (`-32021`).
  *
  * @see {@link https://www.jsonrpc.org/specification#error_object | JSON-RPC 2.0 Error Object}
  *
- * @example Roots not supported
- * {@includeCode ./examples/MethodNotFoundError/roots-not-supported.json}
+ * @example Prompts not supported
+ * {@includeCode ./examples/MethodNotFoundError/prompts-not-supported.json}
  *
  * @category Errors
  */
@@ -281,7 +343,6 @@ export interface MethodNotFoundError extends Error {
  * - **Prompts**: Unknown prompt name or missing required arguments
  * - **Pagination**: Invalid or expired cursor values
  * - **Logging**: Invalid log level
- * - **Tasks**: Invalid or nonexistent task ID, invalid cursor, or attempting to cancel a task already in a terminal status
  * - **Elicitation**: Server requests an elicitation mode not declared in client capabilities
  * - **Sampling**: Missing tool result or tool results mixed with other content
  *
@@ -319,24 +380,114 @@ export interface InternalError extends Error {
     code: typeof INTERNAL_ERROR;
 }
 
-// Implementation-specific JSON-RPC error codes [-32000, -32099]
-/** @internal */
-export const URL_ELICITATION_REQUIRED = -32042;
+/*
+ * MCP error codes.
+ *
+ * JSON-RPC 2.0 reserves `-32000` to `-32099` for implementation-defined
+ * server errors. MCP partitions that range:
+ *
+ * - `-32000` to `-32019`: implementation-defined. Existing SDKs and
+ *   implementations use codes here for their own purposes; the specification
+ *   will never define codes in this sub-range, and receivers must not assign
+ *   cross-implementation semantics to them.
+ * - `-32020` to `-32099`: reserved for error codes defined by the MCP
+ *   specification. Every code allocated here is recorded in this file.
+ *   Codes are allocated sequentially starting at `-32020` and proceeding
+ *   toward `-32099`.
+ *
+ * Codes defined by earlier protocol versions remain reserved and are never
+ * reused: `-32002` (resource not found, 2025-11-25 and earlier; replaced by
+ * `-32602`) and `-32042` (URL elicitation required, 2025-11-25 only).
+ */
 
 /**
- * An error response that indicates that the server requires the client to provide additional information via an elicitation request.
+ * Error code returned when the HTTP headers of a request do not match the
+ * corresponding values in the request body, or required headers are
+ * missing or malformed.
  *
- * @example Authorization required
- * {@includeCode ./examples/URLElicitationRequiredError/authorization-required.json}
+ * @category Errors
+ */
+export const HEADER_MISMATCH = -32020;
+
+/**
+ * Error code returned when a server requires a client capability that was
+ * not declared in the request's `clientCapabilities`.
  *
- * @internal
+ * @category Errors
+ */
+export const MISSING_REQUIRED_CLIENT_CAPABILITY = -32021;
+
+/**
+ * Error code returned when the request's protocol version is not supported
+ * by the server.
+ *
+ * @category Errors
+ */
+export const UNSUPPORTED_PROTOCOL_VERSION = -32022;
+
+/**
+ * Returned when a server rejects a request because the values in the HTTP
+ * headers do not match the corresponding values in the request body, or
+ * because required headers are missing or malformed. For HTTP, the response
+ * status code MUST be `400 Bad Request`.
+ *
+ * @example Header mismatch
+ * {@includeCode ./examples/HeaderMismatchError/header-mismatch.json}
+ *
+ * @category Errors
+ */
+export interface HeaderMismatchError extends Omit<JSONRPCErrorResponse, 'error'> {
+    error: Error & {
+        code: typeof HEADER_MISMATCH;
+    };
+}
+
+/**
+ * Returned when the request's protocol version is unknown to the server or
+ * unsupported (e.g., a known experimental or draft version the server has
+ * chosen not to implement). For HTTP, the response status code MUST be
+ * `400 Bad Request`.
+ *
+ * @example Unsupported protocol version
+ * {@includeCode ./examples/UnsupportedProtocolVersionError/unsupported-version.json}
+ *
+ * @category Errors
+ */
+export interface UnsupportedProtocolVersionError extends Omit<JSONRPCErrorResponse, 'error'> {
+    error: Error & {
+        code: typeof UNSUPPORTED_PROTOCOL_VERSION;
+        data: {
+            /**
+             * Protocol versions the server supports. The client should choose a
+             * mutually supported version from this list and retry.
+             */
+            supported: string[];
+            /**
+             * The protocol version that was requested by the client.
+             */
+            requested: string;
+        };
+    };
+}
+
+/**
+ * Returned when processing a request requires a capability the client did not
+ * declare in `clientCapabilities`. For HTTP, the response status code MUST be
+ * `400 Bad Request`.
+ *
+ * @example Missing elicitation capability
+ * {@includeCode ./examples/MissingRequiredClientCapabilityError/missing-elicitation-capability.json}
+ *
+ * @category Errors
  */
-export interface URLElicitationRequiredError extends Omit<JSONRPCErrorResponse, 'error'> {
+export interface MissingRequiredClientCapabilityError extends Omit<JSONRPCErrorResponse, 'error'> {
     error: Error & {
-        code: typeof URL_ELICITATION_REQUIRED;
+        code: typeof MISSING_REQUIRED_CLIENT_CAPABILITY;
         data: {
-            elicitations: ElicitRequestURLParams[];
-            [key: string]: unknown;
+            /**
+             * The capabilities the server requires from the client to process this request.
+             */
+            requiredCapabilities: ClientCapabilities;
         };
     };
 }
@@ -349,6 +500,79 @@ export interface URLElicitationRequiredError extends Omit<JSONRPCErrorResponse,
  */
 export type EmptyResult = Result;
 
+/** @internal */
+export type InputRequest = CreateMessageRequest | ListRootsRequest | ElicitRequest;
+
+/** @internal */
+export type InputResponse = CreateMessageResult | ListRootsResult | ElicitResult;
+
+/**
+ * A map of server-initiated requests that the client must fulfill.
+ * Keys are server-assigned identifiers; values are the request objects.
+ *
+ * @example Elicitation and sampling input requests
+ * {@includeCode ./examples/InputRequests/elicitation-and-sampling-input-requests.json}
+ *
+ * @category Multi Round-Trip
+ */
+export interface InputRequests {
+    [key: string]: InputRequest;
+}
+
+/**
+ * A map of client responses to server-initiated requests.
+ * Keys correspond to the keys in the {@link InputRequests} map;
+ * values are the client's result for each request.
+ *
+ * @example Elicitation and sampling input responses
+ * {@includeCode ./examples/InputResponses/elicitation-and-sampling-input-responses.json}
+ *
+ * @category Multi Round-Trip
+ */
+export interface InputResponses {
+    [key: string]: InputResponse;
+}
+
+/**
+ * An InputRequiredResult sent by the server to indicate that additional input is needed
+ * before the request can be completed.
+ *
+ * At least one of `inputRequests` or `requestState` MUST be present.
+ * @example InputRequiredResult with elicitation and sampling input requests and request state
+ * {@includeCode ./examples/InputRequiredResult/input-required-result-with-elicitation-and-sampling-and-request-state.json}
+ *
+ * @example InputRequiredResult with request state only (load shedding)
+ * {@includeCode ./examples/InputRequiredResult/input-required-result-with-request-state-only.json}
+ *
+ * @category Multi Round-Trip
+ */
+export interface InputRequiredResult extends Result {
+    /* Requests issued by the server that must be complete before the
+     * client can retry the original request.
+     */
+    inputRequests?: InputRequests;
+    /* Request state to be passed back to the server when the client
+     * retries the original request.
+     * Note: The client must treat this as an opaque blob; it must not
+     * interpret it in any way.
+     */
+    requestState?: string;
+}
+
+/* Request parameter type that includes input responses and request state.
+ * These parameters may be included in any client-initiated request.
+ */
+export interface InputResponseRequestParams extends RequestParams {
+    /* New field to carry the responses for the server's requests from the
+     * InputRequiredResult message.  For each key in the response's inputRequests
+     * field, the same key must appear here with the associated response.
+     */
+    inputResponses?: InputResponses;
+    /* Request state passed back to the server from the client.
+     */
+    requestState?: string;
+}
+
 /* Cancellation */
 /**
  * Parameters for a `notifications/cancelled` notification.
@@ -362,11 +586,9 @@ export interface CancelledNotificationParams extends NotificationParams {
     /**
      * The ID of the request to cancel.
      *
-     * This MUST correspond to the ID of a request previously issued in the same direction.
-     * This MUST be provided for cancelling non-task requests.
-     * This MUST NOT be used for cancelling tasks (use the {@link CancelTaskRequest | tasks/cancel} request instead).
+     * This MUST correspond to the ID of a request the client previously issued.
      */
-    requestId?: RequestId;
+    requestId: RequestId;
 
     /**
      * An optional string describing the reason for the cancellation. This MAY be logged or presented to the user.
@@ -375,16 +597,14 @@ export interface CancelledNotificationParams extends NotificationParams {
 }
 
 /**
- * This notification can be sent by either side to indicate that it is cancelling a previously-issued request.
+ * This notification is sent by the client to indicate that it is cancelling a request it previously issued.
+ *
+ * On stdio, the server also sends this notification, solely to terminate a {@link SubscriptionsListenRequest | subscriptions/listen} stream: it references the ID of the `subscriptions/listen` request that opened the stream. Servers MUST NOT use this notification to cancel any other request.
  *
  * The request SHOULD still be in-flight, but due to communication latency, it is always possible that this notification MAY arrive after the request has already finished.
  *
  * This notification indicates that the result will be unused, so any associated processing SHOULD cease.
  *
- * A client MUST NOT attempt to cancel its `initialize` request.
- *
- * For task cancellation, use the {@link CancelTaskRequest | tasks/cancel} request instead of this notification.
- *
  * @example User-requested cancellation
  * {@includeCode ./examples/CancelledNotification/user-requested-cancellation.json}
  *
@@ -395,95 +615,72 @@ export interface CancelledNotification extends JSONRPCNotification {
     params: CancelledNotificationParams;
 }
 
-/* Initialization */
+/* Discovery */
 /**
- * Parameters for an `initialize` request.
+ * A request from the client asking the server to advertise its supported
+ * protocol versions, capabilities, and other metadata. Servers **MUST**
+ * implement `server/discover`. Clients **MAY** call it but are not required
+ * to — version negotiation can also happen inline via per-request `_meta`.
  *
- * @example Full client capabilities
- * {@includeCode ./examples/InitializeRequestParams/full-client-capabilities.json}
+ * @example Discover request
+ * {@includeCode ./examples/DiscoverRequest/server-discover-request.json}
  *
- * @category `initialize`
+ * @category `server/discover`
  */
-export interface InitializeRequestParams extends RequestParams {
-    /**
-     * The latest version of the Model Context Protocol that the client supports. The client MAY decide to support older versions as well.
-     */
-    protocolVersion: string;
-    capabilities: ClientCapabilities;
-    clientInfo: Implementation;
+export interface DiscoverRequest extends JSONRPCRequest {
+    method: 'server/discover';
+    params: RequestParams;
 }
 
 /**
- * This request is sent from the client to the server when it first connects, asking it to begin initialization.
+ * The result returned by the server for a {@link DiscoverRequest | server/discover} request.
  *
- * @example Initialize request
- * {@includeCode ./examples/InitializeRequest/initialize-request.json}
+ * @example Server capabilities discovery
+ * {@includeCode ./examples/DiscoverResult/server-capabilities-discovery.json}
  *
- * @category `initialize`
+ * @category `server/discover`
  */
-export interface InitializeRequest extends JSONRPCRequest {
-    method: 'initialize';
-    params: InitializeRequestParams;
-}
-
-/**
- * The result returned by the server for an {@link InitializeRequest | initialize} request.
- *
- * @example Full server capabilities
- * {@includeCode ./examples/InitializeResult/full-server-capabilities.json}
- *
- * @category `initialize`
- */
-export interface InitializeResult extends Result {
+export interface DiscoverResult extends CacheableResult {
     /**
-     * The version of the Model Context Protocol that the server wants to use. This may not match the version that the client requested. If the client cannot support this version, it MUST disconnect.
+     * MCP Protocol Versions this server supports. The client should choose a
+     * version from this list for use in subsequent requests.
+     */
+    supportedVersions: string[];
+    /**
+     * The capabilities of the server.
      */
-    protocolVersion: string;
     capabilities: ServerCapabilities;
+    /**
+     * Information about the server software implementation.
+     */
     serverInfo: Implementation;
-
     /**
-     * Instructions describing how to use the server and its features.
-     *
-     * Instructions should focus on information that helps the model use the server effectively (e.g., cross-tool relationships, workflow patterns, constraints), but should not duplicate information already in tool descriptions.
+     * Natural-language guidance describing the server and its features.
      *
-     * Clients MAY add this information to the system prompt.
-     *
-     * @example Server with workflow instructions
-     * {@includeCode ./examples/InitializeResult/with-instructions.json}
+     * This can be used by clients to improve an LLM's understanding of
+     * available tools (e.g., by including it in a system prompt). It should
+     * focus on information that helps the model use the server effectively
+     * and should not duplicate information already in tool descriptions.
      */
     instructions?: string;
 }
 
 /**
- * A successful response from the server for a {@link InitializeRequest | initialize} request.
+ * A successful response from the server for a {@link DiscoverRequest | server/discover} request.
  *
- * @example Initialize result response
- * {@includeCode ./examples/InitializeResultResponse/initialize-result-response.json}
+ * @example Discover result response
+ * {@includeCode ./examples/DiscoverResultResponse/discover-result-response.json}
  *
- * @category `initialize`
+ * @category `server/discover`
  */
-export interface InitializeResultResponse extends JSONRPCResultResponse {
-    result: InitializeResult;
-}
-
-/**
- * This notification is sent from the client to the server after initialization has finished.
- *
- * @example Initialized notification
- * {@includeCode ./examples/InitializedNotification/initialized-notification.json}
- *
- * @category `notifications/initialized`
- */
-export interface InitializedNotification extends JSONRPCNotification {
-    method: 'notifications/initialized';
-    params?: NotificationParams;
+export interface DiscoverResultResponse extends JSONRPCResultResponse {
+    result: DiscoverResult;
 }
 
 /**
  * Capabilities a client may support. Known capabilities are defined here, in this schema, but this is not a closed set: any client can define its own, additional capabilities.
  *
- * @category `initialize`
+ * @category `server/discover`
  */
 export interface ClientCapabilities {
     /**
@@ -493,29 +690,30 @@ export interface ClientCapabilities {
     /**
      * Present if the client supports listing roots.
      *
+     * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+     * Remains in the specification for at least twelve months; see the
+     * deprecated features registry.
+     *
      * @example Roots — minimum baseline support
      * {@includeCode ./examples/ClientCapabilities/roots-minimum-baseline-support.json}
-     *
-     * @example Roots — list changed notifications
-     * {@includeCode ./examples/ClientCapabilities/roots-list-changed-notifications.json}
      */
-    roots?: {
-        /**
-         * Whether the client supports notifications for changes to the roots list.
-         */
-        listChanged?: boolean;
-    };
+    // eslint-disable-next-line @typescript-eslint/no-empty-object-type
+    roots?: {};
     /**
      * Present if the client supports sampling from an LLM.
      *
+     * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+     * Remains in the specification for at least twelve months; see the
+     * deprecated features registry.
+     *
      * @example Sampling — minimum baseline support
      * {@includeCode ./examples/ClientCapabilities/sampling-minimum-baseline-support.json}
      *
      * @example Sampling — tool use support
      * {@includeCode ./examples/ClientCapabilities/sampling-tool-use-support.json}
      *
-     * @example Sampling — context inclusion support (soft-deprecated)
-     * {@includeCode ./examples/ClientCapabilities/sampling-context-inclusion-support-soft-deprecated.json}
+     * @example Sampling — context inclusion support (deprecated)
+     * {@includeCode ./examples/ClientCapabilities/sampling-context-inclusion-support-deprecated.json}
      */
     sampling?: {
         /**
@@ -542,48 +740,15 @@ export interface ClientCapabilities {
         url?: JSONObject;
     };
 
-    /**
-     * Present if the client supports task-augmented requests.
-     */
-    tasks?: {
-        /**
-         * Whether this client supports {@link ListTasksRequest | tasks/list}.
-         */
-        list?: JSONObject;
-        /**
-         * Whether this client supports {@link CancelTaskRequest | tasks/cancel}.
-         */
-        cancel?: JSONObject;
-        /**
-         * Specifies which request types can be augmented with tasks.
-         */
-        requests?: {
-            /**
-             * Task support for sampling-related requests.
-             */
-            sampling?: {
-                /**
-                 * Whether the client supports task-augmented `sampling/createMessage` requests.
-                 */
-                createMessage?: JSONObject;
-            };
-            /**
-             * Task support for elicitation-related requests.
-             */
-            elicitation?: {
-                /**
-                 * Whether the client supports task-augmented {@link ElicitRequest | elicitation/create} requests.
-                 */
-                create?: JSONObject;
-            };
-        };
-    };
     /**
      * Optional MCP extensions that the client supports. Keys are extension identifiers
      * (e.g., "io.modelcontextprotocol/oauth-client-credentials"), and values are
      * per-extension settings objects. An empty object indicates support with no settings.
      *
-     * @example Extensions — UI extension with MIME type support
+     * Keys MUST follow the {@link MetaObject | `_meta` key naming rules}, with a
+     * mandatory prefix.
+     *
+     * @example Extensions — MCP Apps (UI) extension with MIME type support
      * {@includeCode ./examples/ClientCapabilities/extensions-ui-mime-types.json}
      */
     extensions?: { [key: string]: JSONObject };
@@ -592,7 +757,7 @@ export interface ClientCapabilities {
 /**
  * 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.
  *
- * @category `initialize`
+ * @category `server/discover`
  */
 export interface ServerCapabilities {
     /**
@@ -602,6 +767,10 @@ export interface ServerCapabilities {
     /**
      * Present if the server supports sending log messages to the client.
      *
+     * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+     * Remains in the specification for at least twelve months; see the
+     * deprecated features registry.
+     *
      * @example Logging — minimum baseline support
      * {@includeCode ./examples/ServerCapabilities/logging-minimum-baseline-support.json}
      */
@@ -668,40 +837,16 @@ export interface ServerCapabilities {
          */
         listChanged?: boolean;
     };
-    /**
-     * Present if the server supports task-augmented requests.
-     */
-    tasks?: {
-        /**
-         * Whether this server supports {@link ListTasksRequest | tasks/list}.
-         */
-        list?: JSONObject;
-        /**
-         * Whether this server supports {@link CancelTaskRequest | tasks/cancel}.
-         */
-        cancel?: JSONObject;
-        /**
-         * Specifies which request types can be augmented with tasks.
-         */
-        requests?: {
-            /**
-             * Task support for tool-related requests.
-             */
-            tools?: {
-                /**
-                 * Whether the server supports task-augmented {@link CallToolRequest | tools/call} requests.
-                 */
-                call?: JSONObject;
-            };
-        };
-    };
     /**
      * Optional MCP extensions that the server supports. Keys are extension identifiers
-     * (e.g., "io.modelcontextprotocol/apps"), and values are per-extension settings
+     * (e.g., "io.modelcontextprotocol/tasks"), and values are per-extension settings
      * objects. An empty object indicates support with no settings.
      *
-     * @example Extensions — UI extension support
-     * {@includeCode ./examples/ServerCapabilities/extensions-ui.json}
+     * Keys MUST follow the {@link MetaObject | `_meta` key naming rules}, with a
+     * mandatory prefix.
+     *
+     * @example Extensions — Tasks extension support
+     * {@includeCode ./examples/ServerCapabilities/extensions-tasks.json}
      */
     extensions?: { [key: string]: JSONObject };
 }
@@ -795,7 +940,7 @@ export interface BaseMetadata {
 /**
  * Describes the MCP implementation.
  *
- * @category `initialize`
+ * @category `server/discover`
  */
 export interface Implementation extends BaseMetadata, Icons {
     /**
@@ -820,32 +965,6 @@ export interface Implementation extends BaseMetadata, Icons {
     websiteUrl?: string;
 }
 
-/* Ping */
-/**
- * A ping, issued by either the server or the client, to check that the other party is still alive. The receiver must promptly respond, or else may be disconnected.
- *
- * @example Ping request
- * {@includeCode ./examples/PingRequest/ping-request.json}
- *
- * @category `ping`
- */
-export interface PingRequest extends JSONRPCRequest {
-    method: 'ping';
-    params?: RequestParams;
-}
-
-/**
- * A successful response for a {@link PingRequest | ping} request.
- *
- * @example Ping result response
- * {@includeCode ./examples/PingResultResponse/ping-result-response.json}
- *
- * @category `ping`
- */
-export interface PingResultResponse extends JSONRPCResultResponse {
-    result: EmptyResult;
-}
-
 /* Progress notifications */
 
 /**
@@ -911,7 +1030,7 @@ export interface PaginatedRequestParams extends RequestParams {
 
 /** @internal */
 export interface PaginatedRequest extends JSONRPCRequest {
-    params?: PaginatedRequestParams;
+    params: PaginatedRequestParams;
 }
 
 /** @internal */
@@ -923,6 +1042,42 @@ export interface PaginatedResult extends Result {
     nextCursor?: Cursor;
 }
 
+/**
+ * A result that supports a time-to-live (TTL) hint for client-side caching.
+ *
+ * @internal
+ */
+export interface CacheableResult extends Result {
+    /**
+     * A hint from the server indicating how long (in milliseconds) the
+     * client MAY cache this response before re-fetching. Semantics are
+     * analogous to HTTP Cache-Control max-age.
+     *
+     * - If 0, The response SHOULD be considered immediately stale,
+     *   The client MAY re-fetch every time the result is needed.
+     * - If positive, the client SHOULD consider the result fresh for this many
+     *   milliseconds after receiving the response.
+     *
+     * @minimum 0
+     */
+    ttlMs: number;
+
+    /**
+     * Indicates the intended scope of the cached response, analogous to HTTP
+     * `Cache-Control: public` vs `Cache-Control: private`.
+     *
+     * - `"public"`: The response does not contain user-specific data. Any
+     *   client or intermediary (e.g., shared gateway, caching proxy) MAY cache
+     *   the response and serve it across authorization contexts.
+     * - `"private"`: The response MAY be cached and reused only within the
+     *   same authorization context. Caches MUST NOT be shared across
+     *   authorization contexts (e.g., a different access token requires a
+     *   different cache).
+     *
+     */
+    cacheScope: 'public' | 'private';
+}
+
 /* Resources */
 /**
  * Sent from the client to request a list of resources the server has.
@@ -939,12 +1094,12 @@ export interface ListResourcesRequest extends PaginatedRequest {
 /**
  * The result returned by the server for a {@link ListResourcesRequest | resources/list} request.
  *
- * @example Resources list with cursor
- * {@includeCode ./examples/ListResourcesResult/resources-list-with-cursor.json}
+ * @example Resources list with cursor and TTL
+ * {@includeCode ./examples/ListResourcesResult/resources-list-with-cursor-and-ttl.json}
  *
  * @category `resources/list`
  */
-export interface ListResourcesResult extends PaginatedResult {
+export interface ListResourcesResult extends PaginatedResult, CacheableResult {
     resources: Resource[];
 }
 
@@ -975,12 +1130,12 @@ export interface ListResourceTemplatesRequest extends PaginatedRequest {
 /**
  * The result returned by the server for a {@link ListResourceTemplatesRequest | resources/templates/list} request.
  *
- * @example Resource templates list
- * {@includeCode ./examples/ListResourceTemplatesResult/resource-templates-list.json}
+ * @example Resource templates list with cursor and TTL
+ * {@includeCode ./examples/ListResourceTemplatesResult/resource-templates-list-with-cursor-and-ttl.json}
  *
  * @category `resources/templates/list`
  */
-export interface ListResourceTemplatesResult extends PaginatedResult {
+export interface ListResourceTemplatesResult extends PaginatedResult, CacheableResult {
     resourceTemplates: ResourceTemplate[];
 }
 
@@ -1015,8 +1170,7 @@ export interface ResourceRequestParams extends RequestParams {
  *
  * @category `resources/read`
  */
-// eslint-disable-next-line @typescript-eslint/no-empty-object-type
-export interface ReadResourceRequestParams extends ResourceRequestParams {}
+export interface ReadResourceRequestParams extends ResourceRequestParams, InputResponseRequestParams {}
 
 /**
  * Sent from the client to the server, to read a specific resource URI.
@@ -1039,7 +1193,7 @@ export interface ReadResourceRequest extends JSONRPCRequest {
  *
  * @category `resources/read`
  */
-export interface ReadResourceResult extends Result {
+export interface ReadResourceResult extends CacheableResult {
     contents: (TextResourceContents | BlobResourceContents)[];
 }
 
@@ -1049,14 +1203,17 @@ export interface ReadResourceResult extends Result {
  * @example Read resource result response
  * {@includeCode ./examples/ReadResourceResultResponse/read-resource-result-response.json}
  *
+ * @example Read resource result response with TTL
+ * {@includeCode ./examples/ReadResourceResultResponse/read-resource-result-response-with-ttl.json}
+ *
  * @category `resources/read`
  */
 export interface ReadResourceResultResponse extends JSONRPCResultResponse {
-    result: ReadResourceResult;
+    result: ReadResourceResult | InputRequiredResult;
 }
 
 /**
- * An optional notification from the server to the client, informing it that the list of resources it can read from has changed. This may be issued by servers without any previous subscription from the client.
+ * An optional notification from the server to the client, informing it that the list of resources it can read from has changed. This is only delivered on a {@link SubscriptionsListenRequest | subscriptions/listen} stream when the client requested it via the `resourcesListChanged` filter field.
  *
  * @example Resources list changed
  * {@includeCode ./examples/ResourceListChangedNotification/resources-list-changed.json}
@@ -1069,72 +1226,92 @@ export interface ResourceListChangedNotification extends JSONRPCNotification {
 }
 
 /**
- * Parameters for a `resources/subscribe` request.
+ * The set of notification types a client may opt in to on a
+ * {@link SubscriptionsListenRequest | subscriptions/listen} request.
  *
- * @example Subscribe to file resource
- * {@includeCode ./examples/SubscribeRequestParams/subscribe-to-file-resource.json}
+ * Each notification type is **opt-in**; the server **MUST NOT** send
+ * notification types the client has not explicitly requested here.
  *
- * @category `resources/subscribe`
+ * @category `subscriptions/listen`
  */
-// eslint-disable-next-line @typescript-eslint/no-empty-object-type
-export interface SubscribeRequestParams extends ResourceRequestParams {}
+export interface SubscriptionFilter {
+    /**
+     * If true, receive {@link ToolListChangedNotification | notifications/tools/list_changed}.
+     */
+    toolsListChanged?: boolean;
+    /**
+     * If true, receive {@link PromptListChangedNotification | notifications/prompts/list_changed}.
+     */
+    promptsListChanged?: boolean;
+    /**
+     * If true, receive {@link ResourceListChangedNotification | notifications/resources/list_changed}.
+     */
+    resourcesListChanged?: boolean;
+    /**
+     * Subscribe to {@link ResourceUpdatedNotification | notifications/resources/updated} for these resource URIs.
+     * Replaces the former `resources/subscribe` RPC.
+     */
+    resourceSubscriptions?: string[];
+}
 
 /**
- * Sent from the client to request {@link ResourceUpdatedNotification | resources/updated} notifications from the server whenever a particular resource changes.
- *
- * @example Subscribe request
- * {@includeCode ./examples/SubscribeRequest/subscribe-request.json}
+ * Parameters for a {@link SubscriptionsListenRequest | subscriptions/listen} request.
  *
- * @category `resources/subscribe`
+ * @category `subscriptions/listen`
  */
-export interface SubscribeRequest extends JSONRPCRequest {
-    method: 'resources/subscribe';
-    params: SubscribeRequestParams;
+export interface SubscriptionsListenRequestParams extends RequestParams {
+    /**
+     * The notifications the client opts in to on this stream. The server
+     * **MUST NOT** send notification types the client has not explicitly
+     * requested.
+     */
+    notifications: SubscriptionFilter;
 }
 
 /**
- * A successful response from the server for a {@link SubscribeRequest | resources/subscribe} request.
+ * Sent from the client to open a long-lived channel for receiving notifications
+ * outside the context of a specific request. Replaces the previous HTTP GET
+ * endpoint and ensures consistent behavior between HTTP and STDIO.
  *
- * @example Subscribe result response
- * {@includeCode ./examples/SubscribeResultResponse/subscribe-result-response.json}
+ * @example Listen for tools and resource list changes
+ * {@includeCode ./examples/SubscriptionsListenRequest/listen-for-list-changes.json}
  *
- * @category `resources/subscribe`
+ * @category `subscriptions/listen`
  */
-export interface SubscribeResultResponse extends JSONRPCResultResponse {
-    result: EmptyResult;
+export interface SubscriptionsListenRequest extends JSONRPCRequest {
+    method: 'subscriptions/listen';
+    params: SubscriptionsListenRequestParams;
 }
 
 /**
- * Parameters for a `resources/unsubscribe` request.
+ * Parameters for a {@link SubscriptionsAcknowledgedNotification | notifications/subscriptions/acknowledged} notification.
  *
- * @category `resources/unsubscribe`
+ * @category `notifications/subscriptions/acknowledged`
  */
-// eslint-disable-next-line @typescript-eslint/no-empty-object-type
-export interface UnsubscribeRequestParams extends ResourceRequestParams {}
-
-/**
- * Sent from the client to request cancellation of {@link ResourceUpdatedNotification | resources/updated} notifications from the server. This should follow a previous {@link SubscribeRequest | resources/subscribe} request.
- *
- * @example Unsubscribe request
- * {@includeCode ./examples/UnsubscribeRequest/unsubscribe-request.json}
- *
- * @category `resources/unsubscribe`
- */
-export interface UnsubscribeRequest extends JSONRPCRequest {
-    method: 'resources/unsubscribe';
-    params: UnsubscribeRequestParams;
+export interface SubscriptionsAcknowledgedNotificationParams extends NotificationParams {
+    /**
+     * The subset of requested notification types the server agreed to honor.
+     * Only includes notification types the server actually supports; if the
+     * client requested an unsupported type (e.g., `promptsListChanged` when
+     * the server has no prompts), it is omitted from this set.
+     */
+    notifications: SubscriptionFilter;
 }
 
 /**
- * A successful response from the server for a {@link UnsubscribeRequest | resources/unsubscribe} request.
+ * Sent by the server as the first message on a
+ * {@link SubscriptionsListenRequest | subscriptions/listen} stream to acknowledge
+ * that the subscription has been established and to report which notification
+ * types it agreed to honor.
  *
- * @example Unsubscribe result response
- * {@includeCode ./examples/UnsubscribeResultResponse/unsubscribe-result-response.json}
+ * @example Listen acknowledged
+ * {@includeCode ./examples/SubscriptionsAcknowledgedNotification/listen-acknowledged.json}
  *
- * @category `resources/unsubscribe`
+ * @category `notifications/subscriptions/acknowledged`
  */
-export interface UnsubscribeResultResponse extends JSONRPCResultResponse {
-    result: EmptyResult;
+export interface SubscriptionsAcknowledgedNotification extends JSONRPCNotification {
+    method: 'notifications/subscriptions/acknowledged';
+    params: SubscriptionsAcknowledgedNotificationParams;
 }
 
 /**
@@ -1155,7 +1332,7 @@ export interface ResourceUpdatedNotificationParams extends NotificationParams {
 }
 
 /**
- * A notification from the server to the client, informing it that a resource has changed and may need to be read again. This should only be sent if the client previously sent a {@link SubscribeRequest | resources/subscribe} request.
+ * A notification from the server to the client, informing it that a resource has changed and may need to be read again. This is only sent for resources the client opted in to via the `resourceSubscriptions` field of a {@link SubscriptionsListenRequest | subscriptions/listen} request.
  *
  * @example File resource updated notification
  * {@includeCode ./examples/ResourceUpdatedNotification/file-resource-updated-notification.json}
@@ -1307,12 +1484,12 @@ export interface ListPromptsRequest extends PaginatedRequest {
 /**
  * The result returned by the server for a {@link ListPromptsRequest | prompts/list} request.
  *
- * @example Prompts list with cursor
- * {@includeCode ./examples/ListPromptsResult/prompts-list-with-cursor.json}
+ * @example Prompts list with cursor and TTL
+ * {@includeCode ./examples/ListPromptsResult/prompts-list-with-cursor-and-ttl.json}
  *
  * @category `prompts/list`
  */
-export interface ListPromptsResult extends PaginatedResult {
+export interface ListPromptsResult extends PaginatedResult, CacheableResult {
     prompts: Prompt[];
 }
 
@@ -1336,7 +1513,7 @@ export interface ListPromptsResultResponse extends JSONRPCResultResponse {
  *
  * @category `prompts/get`
  */
-export interface GetPromptRequestParams extends RequestParams {
+export interface GetPromptRequestParams extends InputResponseRequestParams {
     /**
      * The name of the prompt or prompt template.
      */
@@ -1385,7 +1562,7 @@ export interface GetPromptResult extends Result {
  * @category `prompts/get`
  */
 export interface GetPromptResultResponse extends JSONRPCResultResponse {
-    result: GetPromptResult;
+    result: GetPromptResult | InputRequiredResult;
 }
 
 /**
@@ -1480,7 +1657,7 @@ export interface EmbeddedResource {
     _meta?: MetaObject;
 }
 /**
- * An optional notification from the server to the client, informing it that the list of prompts it offers has changed. This may be issued by servers without any previous subscription from the client.
+ * An optional notification from the server to the client, informing it that the list of prompts it offers has changed. This is only delivered on a {@link SubscriptionsListenRequest | subscriptions/listen} stream when the client requested it via the `promptsListChanged` filter field.
  *
  * @example Prompts list changed
  * {@includeCode ./examples/PromptListChangedNotification/prompts-list-changed.json}
@@ -1508,12 +1685,12 @@ export interface ListToolsRequest extends PaginatedRequest {
 /**
  * The result returned by the server for a {@link ListToolsRequest | tools/list} request.
  *
- * @example Tools list with cursor
- * {@includeCode ./examples/ListToolsResult/tools-list-with-cursor.json}
+ * @example Tools list with cursor and TTL
+ * {@includeCode ./examples/ListToolsResult/tools-list-with-cursor-and-ttl.json}
  *
  * @category `tools/list`
  */
-export interface ListToolsResult extends PaginatedResult {
+export interface ListToolsResult extends PaginatedResult, CacheableResult {
     tools: Tool[];
 }
 
@@ -1550,9 +1727,12 @@ export interface CallToolResult extends Result {
     content: ContentBlock[];
 
     /**
-     * An optional JSON object that represents the structured result of the tool call.
+     * An optional JSON value that represents the structured result of the tool call.
+     *
+     * This can be any JSON value (object, array, string, number, boolean, or null)
+     * that conforms to the tool's outputSchema if one is defined.
      */
-    structuredContent?: { [key: string]: unknown };
+    structuredContent?: unknown;
 
     /**
      * Whether the tool call ended in an error.
@@ -1580,7 +1760,7 @@ export interface CallToolResult extends Result {
  * @category `tools/call`
  */
 export interface CallToolResultResponse extends JSONRPCResultResponse {
-    result: CallToolResult;
+    result: CallToolResult | InputRequiredResult;
 }
 
 /**
@@ -1594,7 +1774,7 @@ export interface CallToolResultResponse extends JSONRPCResultResponse {
  *
  * @category `tools/call`
  */
-export interface CallToolRequestParams extends TaskAugmentedRequestParams {
+export interface CallToolRequestParams extends InputResponseRequestParams {
     /**
      * The name of the tool.
      */
@@ -1619,7 +1799,7 @@ export interface CallToolRequest extends JSONRPCRequest {
 }
 
 /**
- * An optional notification from the server to the client, informing it that the list of tools it offers has changed. This may be issued by servers without any previous subscription from the client.
+ * An optional notification from the server to the client, informing it that the list of tools it offers has changed. This is only delivered on a {@link SubscriptionsListenRequest | subscriptions/listen} stream when the client requested it via the `toolsListChanged` filter field.
  *
  * @example Tools list changed
  * {@includeCode ./examples/ToolListChangedNotification/tools-list-changed.json}
@@ -1687,26 +1867,6 @@ export interface ToolAnnotations {
     openWorldHint?: boolean;
 }
 
-/**
- * Execution-related properties for a tool.
- *
- * @category `tools/list`
- */
-export interface ToolExecution {
-    /**
-     * Indicates whether this tool supports task-augmented execution.
-     * This allows clients to handle long-running operations through polling
-     * the task system.
-     *
-     * - `"forbidden"`: Tool does not support task-augmented execution (default when absent)
-     * - `"optional"`: Tool may support task-augmented execution
-     * - `"required"`: Tool requires task-augmented execution
-     *
-     * Default: `"forbidden"`
-     */
-    taskSupport?: 'forbidden' | 'optional' | 'required';
-}
-
 /**
  * Definition for a tool the client can call.
  *
@@ -1734,32 +1894,29 @@ export interface Tool extends BaseMetadata, Icons {
 
     /**
      * A JSON Schema object defining the expected parameters for the tool.
+     *
+     * Tool arguments are always JSON objects, so `type: "object"` is required at the root.
+     * Beyond that, any JSON Schema 2020-12 keyword may appear alongside `type` — including
+     * composition keywords (`oneOf`, `anyOf`, `allOf`, `not`), conditional keywords
+     * (`if`/`then`/`else`), reference keywords (`$ref`, `$defs`, `$anchor`), and any other
+     * standard validation or annotation keywords.
+     *
+     * Property schemas may carry an `x-mcp-header` annotation to mirror the
+     * argument value into an HTTP header on the Streamable HTTP transport. See
+     * the Streamable HTTP transport specification for the validity and
+     * extraction rules.
+     *
+     * Defaults to JSON Schema 2020-12 when no explicit `$schema` is provided.
      */
-    inputSchema: {
-        $schema?: string;
-        type: 'object';
-        properties?: { [key: string]: JSONValue };
-        required?: string[];
-    };
-
-    /**
-     * Execution-related properties for this tool.
-     */
-    execution?: ToolExecution;
+    inputSchema: { $schema?: string; type: 'object'; [key: string]: unknown };
 
     /**
      * An optional JSON Schema object defining the structure of the tool's output returned in
-     * the structuredContent field of a {@link CallToolResult}.
+     * the structuredContent field of a {@link CallToolResult}. This can be any valid JSON Schema 2020-12.
      *
      * Defaults to JSON Schema 2020-12 when no explicit `$schema` is provided.
-     * Currently restricted to `type: "object"` at the root level.
      */
-    outputSchema?: {
-        $schema?: string;
-        type: 'object';
-        properties?: { [key: string]: JSONValue };
-        required?: string[];
-    };
+    outputSchema?: { $schema?: string; [key: string]: unknown };
 
     /**
      * Optional additional tool information.
@@ -1771,297 +1928,15 @@ export interface Tool extends BaseMetadata, Icons {
     _meta?: MetaObject;
 }
 
-/* Tasks */
-
-/**
- * The status of a task.
- *
- * @category `tasks`
- */
-export type TaskStatus =
-    | 'working' // The request is currently being processed
-    | 'input_required' // The task is waiting for input (e.g., elicitation or sampling)
-    | 'completed' // The request completed successfully and results are available
-    | 'failed' // The associated request did not complete successfully. For tool calls specifically, this includes cases where the tool call result has `isError` set to true.
-    | 'cancelled'; // The request was cancelled before completion
-
-/**
- * Metadata for augmenting a request with task execution.
- * Include this in the `task` field of the request parameters.
- *
- * @category `tasks`
- */
-export interface TaskMetadata {
-    /**
-     * Requested duration in milliseconds to retain task from creation.
-     */
-    ttl?: number;
-}
-
-/**
- * Metadata for associating messages with a task.
- * Include this in the `_meta` field under the key `io.modelcontextprotocol/related-task`.
- *
- * @category `tasks`
- */
-export interface RelatedTaskMetadata {
-    /**
-     * The task identifier this message is associated with.
-     */
-    taskId: string;
-}
-
-/**
- * Data associated with a task.
- *
- * @category `tasks`
- */
-export interface Task {
-    /**
-     * The task identifier.
-     */
-    taskId: string;
-
-    /**
-     * Current task state.
-     */
-    status: TaskStatus;
-
-    /**
-     * Optional human-readable message describing the current task state.
-     * This can provide context for any status, including:
-     * - Reasons for "cancelled" status
-     * - Summaries for "completed" status
-     * - Diagnostic information for "failed" status (e.g., error details, what went wrong)
-     */
-    statusMessage?: string;
-
-    /**
-     * ISO 8601 timestamp when the task was created.
-     */
-    createdAt: string;
-
-    /**
-     * ISO 8601 timestamp when the task was last updated.
-     */
-    lastUpdatedAt: string;
-
-    /**
-     * Actual retention duration from creation in milliseconds, null for unlimited.
-     * @nullable
-     */
-    ttl: number | null;
-
-    /**
-     * Suggested polling interval in milliseconds.
-     */
-    pollInterval?: number;
-}
-
-/**
- * The result returned for a task-augmented request.
- *
- * @category `tasks`
- */
-export interface CreateTaskResult extends Result {
-    task: Task;
-}
-
-/**
- * A successful response for a task-augmented request.
- *
- * @category `tasks`
- */
-export interface CreateTaskResultResponse extends JSONRPCResultResponse {
-    result: CreateTaskResult;
-}
-
-/**
- * A request to retrieve the state of a task.
- *
- * @category `tasks/get`
- */
-export interface GetTaskRequest extends JSONRPCRequest {
-    method: 'tasks/get';
-    params: {
-        /**
-         * The task identifier to query.
-         */
-        taskId: string;
-    };
-}
-
-/**
- * The result returned for a {@link GetTaskRequest | tasks/get} request.
- *
- * @category `tasks/get`
- */
-export type GetTaskResult = Result & Task;
-
-/**
- * A successful response for a {@link GetTaskRequest | tasks/get} request.
- *
- * @category `tasks/get`
- */
-export interface GetTaskResultResponse extends JSONRPCResultResponse {
-    result: GetTaskResult;
-}
-
-/**
- * A request to retrieve the result of a completed task.
- *
- * @category `tasks/result`
- */
-export interface GetTaskPayloadRequest extends JSONRPCRequest {
-    method: 'tasks/result';
-    params: {
-        /**
-         * The task identifier to retrieve results for.
-         */
-        taskId: string;
-    };
-}
-
-/**
- * The result returned for a {@link GetTaskPayloadRequest | tasks/result} request.
- * The structure matches the result type of the original request.
- * For example, a {@link CallToolRequest | tools/call} task would return the {@link CallToolResult} structure.
- *
- * @category `tasks/result`
- */
-export interface GetTaskPayloadResult extends Result {
-    [key: string]: unknown;
-}
-
-/**
- * A successful response for a {@link GetTaskPayloadRequest | tasks/result} request.
- *
- * @category `tasks/result`
- */
-export interface GetTaskPayloadResultResponse extends JSONRPCResultResponse {
-    result: GetTaskPayloadResult;
-}
-
-/**
- * A request to cancel a task.
- *
- * @category `tasks/cancel`
- */
-export interface CancelTaskRequest extends JSONRPCRequest {
-    method: 'tasks/cancel';
-    params: {
-        /**
-         * The task identifier to cancel.
-         */
-        taskId: string;
-    };
-}
-
-/**
- * The result returned for a {@link CancelTaskRequest | tasks/cancel} request.
- *
- * @category `tasks/cancel`
- */
-export type CancelTaskResult = Result & Task;
-
-/**
- * A successful response for a {@link CancelTaskRequest | tasks/cancel} request.
- *
- * @category `tasks/cancel`
- */
-export interface CancelTaskResultResponse extends JSONRPCResultResponse {
-    result: CancelTaskResult;
-}
-
-/**
- * A request to retrieve a list of tasks.
- *
- * @category `tasks/list`
- */
-export interface ListTasksRequest extends PaginatedRequest {
-    method: 'tasks/list';
-}
-
-/**
- * The result returned for a {@link ListTasksRequest | tasks/list} request.
- *
- * @category `tasks/list`
- */
-export interface ListTasksResult extends PaginatedResult {
-    tasks: Task[];
-}
-
-/**
- * A successful response for a {@link ListTasksRequest | tasks/list} request.
- *
- * @category `tasks/list`
- */
-export interface ListTasksResultResponse extends JSONRPCResultResponse {
-    result: ListTasksResult;
-}
-
-/**
- * Parameters for a `notifications/tasks/status` notification.
- *
- * @category `notifications/tasks/status`
- */
-export type TaskStatusNotificationParams = NotificationParams & Task;
-
-/**
- * An optional notification from the receiver to the requestor, informing them that a task's status has changed. Receivers are not required to send these notifications.
- *
- * @category `notifications/tasks/status`
- */
-export interface TaskStatusNotification extends JSONRPCNotification {
-    method: 'notifications/tasks/status';
-    params: TaskStatusNotificationParams;
-}
-
 /* Logging */
 
-/**
- * Parameters for a `logging/setLevel` request.
- *
- * @example Set log level to "info"
- * {@includeCode ./examples/SetLevelRequestParams/set-log-level-to-info.json}
- *
- * @category `logging/setLevel`
- */
-export interface SetLevelRequestParams extends RequestParams {
-    /**
-     * The level of logging that the client wants to receive from the server. The server should send all logs at this level and higher (i.e., more severe) to the client as {@link LoggingMessageNotification | notifications/message}.
-     */
-    level: LoggingLevel;
-}
-
-/**
- * A request from the client to the server, to enable or adjust logging.
- *
- * @example Set logging level request
- * {@includeCode ./examples/SetLevelRequest/set-logging-level-request.json}
- *
- * @category `logging/setLevel`
- */
-export interface SetLevelRequest extends JSONRPCRequest {
-    method: 'logging/setLevel';
-    params: SetLevelRequestParams;
-}
-
-/**
- * A successful response from the server for a {@link SetLevelRequest | logging/setLevel} request.
- *
- * @example Set logging level result response
- * {@includeCode ./examples/SetLevelResultResponse/set-logging-level-result-response.json}
- *
- * @category `logging/setLevel`
- */
-export interface SetLevelResultResponse extends JSONRPCResultResponse {
-    result: EmptyResult;
-}
-
 /**
  * Parameters for a `notifications/message` notification.
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @example Log database connection failed
  * {@includeCode ./examples/LoggingMessageNotificationParams/log-database-connection-failed.json}
  *
@@ -2083,7 +1958,11 @@ export interface LoggingMessageNotificationParams extends NotificationParams {
 }
 
 /**
- * JSONRPCNotification of a log message passed from server to client. If no `logging/setLevel` request has been sent from the client, the server MAY decide which messages to send automatically.
+ * JSONRPCNotification of a log message passed from server to client. The client opts in by setting `"io.modelcontextprotocol/logLevel"` in a request's `_meta`.
+ *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
  *
  * @example Log database connection failed
  * {@includeCode ./examples/LoggingMessageNotification/log-database-connection-failed.json}
@@ -2101,6 +1980,10 @@ export interface LoggingMessageNotification extends JSONRPCNotification {
  * These map to syslog message severities, as specified in RFC-5424:
  * https://datatracker.ietf.org/doc/html/rfc5424#section-6.2.1
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category Common Types
  */
 export type LoggingLevel = 'debug' | 'info' | 'notice' | 'warning' | 'error' | 'critical' | 'alert' | 'emergency';
@@ -2118,9 +2001,13 @@ export type LoggingLevel = 'debug' | 'info' | 'notice' | 'warning' | 'error' | '
  * @example Follow-up request with tool results
  * {@includeCode ./examples/CreateMessageRequestParams/follow-up-with-tool-results.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
-export interface CreateMessageRequestParams extends TaskAugmentedRequestParams {
+export interface CreateMessageRequestParams {
     messages: SamplingMessage[];
     /**
      * The server's preferences for which model to select. The client MAY ignore these preferences.
@@ -2134,8 +2021,12 @@ export interface CreateMessageRequestParams extends TaskAugmentedRequestParams {
      * A request to include context from one or more MCP servers (including the caller), to be attached to the prompt.
      * The client MAY ignore this request.
      *
-     * Default is `"none"`. Values `"thisServer"` and `"allServers"` are soft-deprecated. Servers SHOULD only use these values if the client
-     * declares {@link ClientCapabilities.sampling.context}. These values may be removed in future spec releases.
+     * Default is `"none"`. The values `"thisServer"` and `"allServers"` are deprecated (SEP-2596): servers SHOULD
+     * omit this field or use `"none"`, and SHOULD only use the deprecated values if the client declares
+     * {@link ClientCapabilities.sampling.context}.
+     *
+     * @deprecated The `"thisServer"` and `"allServers"` values are deprecated as of protocol version 2025-11-25
+     * (SEP-2596) and will be removed no later than the Sampling feature itself (SEP-2577). Omit this field or use `"none"`.
      */
     includeContext?: 'none' | 'thisServer' | 'allServers';
     /**
@@ -2169,6 +2060,10 @@ export interface CreateMessageRequestParams extends TaskAugmentedRequestParams {
 /**
  * Controls tool selection behavior for sampling requests.
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export interface ToolChoice {
@@ -2187,9 +2082,13 @@ export interface ToolChoice {
  * @example Sampling request
  * {@includeCode ./examples/CreateMessageRequest/sampling-request.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
-export interface CreateMessageRequest extends JSONRPCRequest {
+export interface CreateMessageRequest {
     method: 'sampling/createMessage';
     params: CreateMessageRequestParams;
 }
@@ -2208,9 +2107,13 @@ export interface CreateMessageRequest extends JSONRPCRequest {
  * @example Final response after tool use
  * {@includeCode ./examples/CreateMessageResult/final-response.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
-export interface CreateMessageResult extends Result, SamplingMessage {
+export interface CreateMessageResult extends SamplingMessage {
     /**
      * The name of the model that generated the message.
      */
@@ -2230,18 +2133,6 @@ export interface CreateMessageResult extends Result, SamplingMessage {
     stopReason?: 'endTurn' | 'stopSequence' | 'maxTokens' | 'toolUse' | string;
 }
 
-/**
- * A successful response from the client for a {@link CreateMessageRequest | sampling/createMessage} request.
- *
- * @example Sampling result response
- * {@includeCode ./examples/CreateMessageResultResponse/sampling-result-response.json}
- *
- * @category `sampling/createMessage`
- */
-export interface CreateMessageResultResponse extends JSONRPCResultResponse {
-    result: CreateMessageResult;
-}
-
 /**
  * Describes a message issued to or received from an LLM API.
  *
@@ -2251,6 +2142,10 @@ export interface CreateMessageResultResponse extends JSONRPCResultResponse {
  * @example Multiple content blocks
  * {@includeCode ./examples/SamplingMessage/multiple-content-blocks.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export interface SamplingMessage {
@@ -2260,6 +2155,10 @@ export interface SamplingMessage {
 }
 
 /**
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export type SamplingMessageContentBlock = TextContent | ImageContent | AudioContent | ToolUseContent | ToolResultContent;
@@ -2398,6 +2297,10 @@ export interface AudioContent {
  * @example `get_weather` tool use
  * {@includeCode ./examples/ToolUseContent/get-weather-tool-use.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export interface ToolUseContent {
@@ -2433,6 +2336,10 @@ export interface ToolUseContent {
  * @example `get_weather` tool result
  * {@includeCode ./examples/ToolResultContent/get-weather-tool-result.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export interface ToolResultContent {
@@ -2454,11 +2361,12 @@ export interface ToolResultContent {
     content: ContentBlock[];
 
     /**
-     * An optional structured result object.
+     * An optional structured result value.
      *
+     * This can be any JSON value (object, array, string, number, boolean, or null).
      * If the tool defined an {@link Tool.outputSchema}, this SHOULD conform to that schema.
      */
-    structuredContent?: { [key: string]: unknown };
+    structuredContent?: unknown;
 
     /**
      * Whether the tool use resulted in an error.
@@ -2491,6 +2399,10 @@ export interface ToolResultContent {
  * @example With hints and priorities
  * {@includeCode ./examples/ModelPreferences/with-hints-and-priorities.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export interface ModelPreferences {
@@ -2545,6 +2457,10 @@ export interface ModelPreferences {
  * Keys not declared here are currently left unspecified by the spec and are up
  * to the client to interpret.
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `sampling/createMessage`
  */
 export interface ModelHint {
@@ -2693,11 +2609,17 @@ export interface PromptReference extends BaseMetadata {
  * @example List roots request
  * {@includeCode ./examples/ListRootsRequest/list-roots-request.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `roots/list`
  */
-export interface ListRootsRequest extends JSONRPCRequest {
+export interface ListRootsRequest {
     method: 'roots/list';
-    params?: RequestParams;
+    params?: {
+        _meta?: MetaObject;
+    };
 }
 
 /**
@@ -2711,22 +2633,14 @@ export interface ListRootsRequest extends JSONRPCRequest {
  * @example Multiple root directories
  * {@includeCode ./examples/ListRootsResult/multiple-root-directories.json}
  *
- * @category `roots/list`
- */
-export interface ListRootsResult extends Result {
-    roots: Root[];
-}
-
-/**
- * A successful response from the client for a {@link ListRootsRequest | roots/list} request.
- *
- * @example List roots result response
- * {@includeCode ./examples/ListRootsResultResponse/list-roots-result-response.json}
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
  *
  * @category `roots/list`
  */
-export interface ListRootsResultResponse extends JSONRPCResultResponse {
-    result: ListRootsResult;
+export interface ListRootsResult {
+    roots: Root[];
 }
 
 /**
@@ -2735,6 +2649,10 @@ export interface ListRootsResultResponse extends JSONRPCResultResponse {
  * @example Project directory root
  * {@includeCode ./examples/Root/project-directory.json}
  *
+ * @deprecated Deprecated as of protocol version 2026-07-28 (SEP-2577).
+ * Remains in the specification for at least twelve months; see the
+ * deprecated features registry.
+ *
  * @category `roots/list`
  */
 export interface Root {
@@ -2756,21 +2674,6 @@ export interface Root {
     _meta?: MetaObject;
 }
 
-/**
- * A notification from the client to the server, informing it that the list of roots has changed.
- * This notification should be sent whenever the client adds, removes, or modifies any root.
- * The server should then request an updated list of roots using the {@link ListRootsRequest}.
- *
- * @example Roots list changed
- * {@includeCode ./examples/RootsListChangedNotification/roots-list-changed.json}
- *
- * @category `notifications/roots/list_changed`
- */
-export interface RootsListChangedNotification extends JSONRPCNotification {
-    method: 'notifications/roots/list_changed';
-    params?: NotificationParams;
-}
-
 /**
  * The parameters for a request to elicit non-sensitive information from the user via a form in the client.
  *
@@ -2782,7 +2685,7 @@ export interface RootsListChangedNotification extends JSONRPCNotification {
  *
  * @category `elicitation/create`
  */
-export interface ElicitRequestFormParams extends TaskAugmentedRequestParams {
+export interface ElicitRequestFormParams {
     /**
      * The elicitation mode.
      */
@@ -2815,7 +2718,7 @@ export interface ElicitRequestFormParams extends TaskAugmentedRequestParams {
  *
  * @category `elicitation/create`
  */
-export interface ElicitRequestURLParams extends TaskAugmentedRequestParams {
+export interface ElicitRequestURLParams {
     /**
      * The elicitation mode.
      */
@@ -2826,12 +2729,6 @@ export interface ElicitRequestURLParams extends TaskAugmentedRequestParams {
      */
     message: string;
 
-    /**
-     * The ID of the elicitation, which must be unique within the context of the server.
-     * The client MUST treat this ID as an opaque value.
-     */
-    elicitationId: string;
-
     /**
      * The URL that the user should navigate to.
      *
@@ -2855,7 +2752,7 @@ export type ElicitRequestParams = ElicitRequestFormParams | ElicitRequestURLPara
  *
  * @category `elicitation/create`
  */
-export interface ElicitRequest extends JSONRPCRequest {
+export interface ElicitRequest {
     method: 'elicitation/create';
     params: ElicitRequestParams;
 }
@@ -2894,8 +2791,17 @@ export interface NumberSchema {
     type: 'number' | 'integer';
     title?: string;
     description?: string;
+    /**
+     * @TJS-type number
+     */
     minimum?: number;
+    /**
+     * @TJS-type number
+     */
     maximum?: number;
+    /**
+     * @TJS-type number
+     */
     default?: number;
 }
 
@@ -3107,7 +3013,7 @@ export interface LegacyTitledEnumSchema {
 export type EnumSchema = SingleSelectEnumSchema | MultiSelectEnumSchema | LegacyTitledEnumSchema;
 
 /**
- * The result returned by the client for an {@link ElicitRequest | elicitation/create} request.
+ * The result returned by the client for an {@link ElicitRequest| elicitation/create} request.
  *
  * @example Input single field
  * {@includeCode ./examples/ElicitResult/input-single-field.json}
@@ -3120,7 +3026,7 @@ export type EnumSchema = SingleSelectEnumSchema | MultiSelectEnumSchema | Legacy
  *
  * @category `elicitation/create`
  */
-export interface ElicitResult extends Result {
+export interface ElicitResult {
     /**
      * The user action in response to the elicitation.
      * - `"accept"`: User submitted the form/confirmed the action
@@ -3137,87 +3043,27 @@ export interface ElicitResult extends Result {
     content?: { [key: string]: string | number | boolean | string[] };
 }
 
-/**
- * A successful response from the client for a {@link ElicitRequest | elicitation/create} request.
- *
- * @example Elicitation result response
- * {@includeCode ./examples/ElicitResultResponse/elicitation-result-response.json}
- *
- * @category `elicitation/create`
- */
-export interface ElicitResultResponse extends JSONRPCResultResponse {
-    result: ElicitResult;
-}
-
-/**
- * An optional notification from the server to the client, informing it of a completion of a out-of-band elicitation request.
- *
- * @example Elicitation complete
- * {@includeCode ./examples/ElicitationCompleteNotification/elicitation-complete.json}
- *
- * @category `notifications/elicitation/complete`
- */
-export interface ElicitationCompleteNotification extends JSONRPCNotification {
-    method: 'notifications/elicitation/complete';
-    params: {
-        /**
-         * The ID of the elicitation that completed.
-         */
-        elicitationId: string;
-    };
-}
-
 /* Client messages */
 /** @internal */
 export type ClientRequest =
-    | PingRequest
-    | InitializeRequest
+    | DiscoverRequest
     | CompleteRequest
-    | SetLevelRequest
     | GetPromptRequest
     | ListPromptsRequest
     | ListResourcesRequest
     | ListResourceTemplatesRequest
     | ReadResourceRequest
-    | SubscribeRequest
-    | UnsubscribeRequest
+    | SubscriptionsListenRequest
     | CallToolRequest
-    | ListToolsRequest
-    | GetTaskRequest
-    | GetTaskPayloadRequest
-    | ListTasksRequest
-    | CancelTaskRequest;
+    | ListToolsRequest;
 
 /** @internal */
-export type ClientNotification =
-    | CancelledNotification
-    | ProgressNotification
-    | InitializedNotification
-    | RootsListChangedNotification
-    | TaskStatusNotification;
+export type ClientNotification = CancelledNotification;
 
 /** @internal */
-export type ClientResult =
-    | EmptyResult
-    | CreateMessageResult
-    | ListRootsResult
-    | ElicitResult
-    | GetTaskResult
-    | GetTaskPayloadResult
-    | ListTasksResult
-    | CancelTaskResult;
+export type ClientResult = EmptyResult;
 
 /* Server messages */
-/** @internal */
-export type ServerRequest =
-    | PingRequest
-    | CreateMessageRequest
-    | ListRootsRequest
-    | ElicitRequest
-    | GetTaskRequest
-    | GetTaskPayloadRequest
-    | ListTasksRequest
-    | CancelTaskRequest;
 
 /** @internal */
 export type ServerNotification =
@@ -3228,13 +3074,12 @@ export type ServerNotification =
     | ResourceListChangedNotification
     | ToolListChangedNotification
     | PromptListChangedNotification
-    | ElicitationCompleteNotification
-    | TaskStatusNotification;
+    | SubscriptionsAcknowledgedNotification;
 
 /** @internal */
 export type ServerResult =
     | EmptyResult
-    | InitializeResult
+    | DiscoverResult
     | CompleteResult
     | GetPromptResult
     | ListPromptsResult
@@ -3242,9 +3087,5 @@ export type ServerResult =
     | ListResourcesResult
     | ReadResourceResult
     | CallToolResult
-    | CreateTaskResult
     | ListToolsResult
-    | GetTaskResult
-    | GetTaskPayloadResult
-    | ListTasksResult
-    | CancelTaskResult;
+    | InputRequiredResult;