mcp_models

Full migration to the MCP 2026-07-28 schema. This is a breaking release — no backward-compatible shim is provided.

• Added:
  • server/discover RPC family: DiscoverRequest, DiscoverResultResponse, DiscoverResult. Servers now advertise capabilities out-of-band instead of via a one-time handshake.
  • subscriptions/listen RPC family: SubscriptionFilter, SubscriptionsListenRequest/SubscriptionsListenRequestParams, SubscriptionsListenResultMetaObject, SubscriptionsListenResult/SubscriptionsListenResultResponse, SubscriptionsAcknowledgedNotification/SubscriptionsAcknowledgedNotificationParams. Replaces resources/subscribe / resources/unsubscribe.
  • Multi-round-trip support: InputRequiredResult, InputResponseRequestParams (base for GetPromptRequestParams, ReadResourceRequestParams, CallToolRequestParams), and resultType-discriminated outcome unions (CallToolResultOutcome, GetPromptResultOutcome, ReadResourceResultOutcome).
  • RequestMetaObject, NotificationMetaObject, ResultMetaObject: purpose-specific _meta shapes replacing the generic, undifferentiated MetaObject on requests/notifications/results. RequestMetaObject now carries per-request protocol negotiation state (protocolVersion, clientCapabilities, clientInfo).
  • New error types: HeaderMismatchError (-32020), MissingRequiredClientCapabilityError (-32021), UnsupportedProtocolVersionError (-32022).
  • CacheScope enum (public/private) and required ttlMs/cacheScope fields on cacheable list/read results.
  • SamplingMessageContentBlock restricted content-block union (deprecated on arrival, SEP-2577).
  • LoggingMessageNotification wrapper class (deprecated on arrival, SEP-2577), joining the pre-existing LoggingMessageNotificationParams.
• Changed (breaking):
  • _meta is now required (non-nullable RequestMetaObject) on RequestParams, PaginatedRequestParams, and every concrete *RequestParams type — protocol version and capabilities are declared on every request instead of once via initialize.
  • Result gained a required-on-the-wire resultType field (defaults to 'complete') and a ResultMetaObject? $meta (was a bare, mis-serialised meta field writing the wrong wire key 'meta' instead of '_meta').
  • CallToolResultResponse.result, GetPromptResultResponse.result, ReadResourceResultResponse.result are now discriminated unions (InputRequiredResult | <Result>) dispatched on resultType.
  • CancelledNotification method fixed from "notification/cancelled" to "notifications/cancelled"; CancelledNotificationParams.requestId is now required.
  • CompleteResultCompletion.value renamed to values (matches the wire key).
  • ResourceTemplateReference.type fixed from "ref/resource_template" to "ref/resource".
  • ElicitRequest.method fixed to "elicitation/create"; ElicitRequestParams is now a proper discriminated union (ElicitRequestFormParams | ElicitRequestURLParams) dispatched on a mode field (was node); dropped the unspecified task/elicitationId fields.
  • ResourceUpdatedNotificationParams reshaped to {_meta?, uri} (was {resourceId, resourceType, data}).
  • Implementation.version is now required.
  • Tool.inputSchema/outputSchema (ToolSchema) now round-trip arbitrary JSON Schema 2020-12 keywords losslessly via additionalData, alongside the existing typed properties/required/type convenience fields.
• Removed:
  • The entire Task system: Task, TaskStatus, TaskMetadata, TaskStatusNotification(+Params), CreateTaskResult(+Response), GetTaskRequest(+Params), GetTaskPayloadRequest/GetTaskPayloadResult(+Response), ListTasksRequest/ListTasksResult(+Response), CancelTaskRequest/CancelTaskResult(+Response), RelatedTaskMetadata. Superseded by resultType: "input_required" + InputRequiredResult.
  • The initialize handshake and ping: InitializeRequest/InitializeRequestParams/InitializeResult/InitializeResultResponse, InitializedNotification, PingRequest/PingResultResponse. The 2026-07-28 schema reference no longer defines these — every request now carries its own protocol negotiation state via RequestMetaObject, and server/discover replaces capability advertisement.
  • logging/setLevel: SetLevelRequest/SetLevelRequestParams/SetLevelResultResponse. Superseded by the (deprecated) RequestMetaObject.logLevel field.
  • ElicitationCompleteNotification/ElicitationCompleteNotificationParams.
  • resources/subscribe / resources/unsubscribe: SubscribeRequest/SubscribeRequestParams/SubscribeResultResponse, UnsubscribeRequestParams/UnsubscribeResultResponse. Superseded by subscriptions/listen.
  • Tool.execution / ToolExecution (a Task-system casualty).
  • The dead, unused TextResourceContent class (singular — distinct from, and not to be confused with, TextResourceContents).
• Deprecated (SEP-2577, remain functional for at least twelve months): LoggingLevel, LoggingMessageNotification(+Params), RequestMetaObject.logLevel, Root, ListRootsRequest, ListRootsResult, CreateMessageRequest(+Params), CreateMessageResult, ModelHint, ModelPreferences, SamplingMessage, SamplingMessageContentBlock, ToolChoice, ToolResultContent, ToolUseContent, LegacyTitledEnumSchema. ClientCapabilities.roots/.sampling and ServerCapabilities.logging remain valid raw-map keys, now documented as deprecated.

• Fixed some incorrect field types in the Dart models (e.g. error field in JSONRPCErrorResponse).
• Updated example code and tests to reflect these corrections.
• Added missing Dart doc comments on some public classes and fields.

• Fixed Pubspec metadata

• Full Dart model coverage for the MCP 2025-11-25 schema.
• MCP base interface with toMap() and named factory TypeName.toMCP(Map) on every type.
• MapMC<K,V> / MapModel<K,V> base classes for types whose serialised form is the map itself.
• McpBuilder helper for declarative server capability registration (tools, resources, prompts, resource templates, custom methods).
• JSON-RPC core types: JSONRPCRequest, JSONRPCNotification, JSONRPCResultResponse, JSONRPCErrorResponse.
• Standard error types: ParseError, InvalidRequestError, MethodNotFoundError, InvalidParamsError, InternalError.
• Initialization types: InitializeRequest, InitializeResult, Implementation, ClientCapabilities, ServerCapabilities.
• Tool types: Tool, ToolSchema, ToolAnnotations, ToolExecution, CallToolRequest, CallToolResult, ListToolsResult.
• Resource types: Resource, ResourceTemplate, TextResourceContents, BlobResourceContents, ReadResourceResult, ListResourcesResult.
• Prompt types: Prompt, PromptArgument, PromptMessage, GetPromptResult, ListPromptsResult.
• Sampling types: CreateMessageRequest, CreateMessageResult, SamplingMessage, ModelPreferences, ModelHint, ToolChoice.
• Elicitation types: ElicitRequest, ElicitResult, StringSchema, NumberSchema, BooleanSchema, UntitledSingleSelectEnumSchema, TitledSingleSelectEnumSchema.
• Task types: Task, TaskStatus, TaskMetadata, ListTasksResult.
• Content block types: TextContent, ImageContent, AudioContent, EmbeddedResource, ResourceLink.
• Notification types: InitializedNotification, CancelledNotification, ProgressNotification, ToolListChangedNotification, ResourceListChangedNotification, LoggingMessageNotificationParams.
• Miscellaneous types: PingRequest, EmptyResult, Annotations, Role, LoggingLevel, MetaObject, Icon, Theme.
• Dart doc comments on all public classes and fields.
• Comprehensive test suite covering serialisation round-trips, enum factories, error codes, and McpBuilder registration.
• End-to-end example in example/mcp_models_example.dart.