McpSchema.java

/*
 * Copyright 2024-2024 the original author or authors.
 */

package io.modelcontextprotocol.spec;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;

import io.modelcontextprotocol.util.Assert;

/**
 * Based on the <a href="http://www.jsonrpc.org/specification">JSON-RPC 2.0
 * specification</a> and the <a href=
 * "https://github.com/modelcontextprotocol/specification/blob/main/schema/2024-11-05/schema.ts">Model
 * Context Protocol Schema</a>.
 *
 * @author Christian Tzolov
 * @author Luca Chang
 * @author Surbhi Bansal
 * @author Anurag Pant
 */
public final class McpSchema {

	private static final Logger logger = LoggerFactory.getLogger(McpSchema.class);

	private McpSchema() {
	}

	@Deprecated
	public static final String LATEST_PROTOCOL_VERSION = ProtocolVersions.MCP_2025_03_26;

	public static final String JSONRPC_VERSION = "2.0";

	public static final String FIRST_PAGE = null;

	// ---------------------------
	// Method Names
	// ---------------------------

	// Lifecycle Methods
	public static final String METHOD_INITIALIZE = "initialize";

	public static final String METHOD_NOTIFICATION_INITIALIZED = "notifications/initialized";

	public static final String METHOD_PING = "ping";

	public static final String METHOD_NOTIFICATION_PROGRESS = "notifications/progress";

	// Tool Methods
	public static final String METHOD_TOOLS_LIST = "tools/list";

	public static final String METHOD_TOOLS_CALL = "tools/call";

	public static final String METHOD_NOTIFICATION_TOOLS_LIST_CHANGED = "notifications/tools/list_changed";

	// Resources Methods
	public static final String METHOD_RESOURCES_LIST = "resources/list";

	public static final String METHOD_RESOURCES_READ = "resources/read";

	public static final String METHOD_NOTIFICATION_RESOURCES_LIST_CHANGED = "notifications/resources/list_changed";

	public static final String METHOD_NOTIFICATION_RESOURCES_UPDATED = "notifications/resources/updated";

	public static final String METHOD_RESOURCES_TEMPLATES_LIST = "resources/templates/list";

	public static final String METHOD_RESOURCES_SUBSCRIBE = "resources/subscribe";

	public static final String METHOD_RESOURCES_UNSUBSCRIBE = "resources/unsubscribe";

	// Prompt Methods
	public static final String METHOD_PROMPT_LIST = "prompts/list";

	public static final String METHOD_PROMPT_GET = "prompts/get";

	public static final String METHOD_NOTIFICATION_PROMPTS_LIST_CHANGED = "notifications/prompts/list_changed";

	public static final String METHOD_COMPLETION_COMPLETE = "completion/complete";

	// Logging Methods
	public static final String METHOD_LOGGING_SET_LEVEL = "logging/setLevel";

	public static final String METHOD_NOTIFICATION_MESSAGE = "notifications/message";

	// Roots Methods
	public static final String METHOD_ROOTS_LIST = "roots/list";

	public static final String METHOD_NOTIFICATION_ROOTS_LIST_CHANGED = "notifications/roots/list_changed";

	// Sampling Methods
	public static final String METHOD_SAMPLING_CREATE_MESSAGE = "sampling/createMessage";

	// Elicitation Methods
	public static final String METHOD_ELICITATION_CREATE = "elicitation/create";

	private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();

	// ---------------------------
	// JSON-RPC Error Codes
	// ---------------------------
	/**
	 * Standard error codes used in MCP JSON-RPC responses.
	 */
	public static final class ErrorCodes {

		/**
		 * Invalid JSON was received by the server.
		 */
		public static final int PARSE_ERROR = -32700;

		/**
		 * The JSON sent is not a valid Request object.
		 */
		public static final int INVALID_REQUEST = -32600;

		/**
		 * The method does not exist / is not available.
		 */
		public static final int METHOD_NOT_FOUND = -32601;

		/**
		 * Invalid method parameter(s).
		 */
		public static final int INVALID_PARAMS = -32602;

		/**
		 * Internal JSON-RPC error.
		 */
		public static final int INTERNAL_ERROR = -32603;

	}

	public sealed interface Request
			permits InitializeRequest, CallToolRequest, CreateMessageRequest, ElicitRequest, CompleteRequest,
			GetPromptRequest, ReadResourceRequest, SubscribeRequest, UnsubscribeRequest, PaginatedRequest {

		Map<String, Object> meta();

		default String progressToken() {
			if (meta() != null && meta().containsKey("progressToken")) {
				return meta().get("progressToken").toString();
			}
			return null;
		}

	}

	public sealed interface Result permits InitializeResult, ListResourcesResult, ListResourceTemplatesResult,
			ReadResourceResult, ListPromptsResult, GetPromptResult, ListToolsResult, CallToolResult,
			CreateMessageResult, ElicitResult, CompleteResult, ListRootsResult {

		Map<String, Object> meta();

	}

	public sealed interface Notification
			permits ProgressNotification, LoggingMessageNotification, ResourcesUpdatedNotification {

		Map<String, Object> meta();

	}

	private static final TypeReference<HashMap<String, Object>> MAP_TYPE_REF = new TypeReference<>() {
	};

	/**
	 * Deserializes a JSON string into a JSONRPCMessage object.
	 * @param objectMapper The ObjectMapper instance to use for deserialization
	 * @param jsonText The JSON string to deserialize
	 * @return A JSONRPCMessage instance using either the {@link JSONRPCRequest},
	 * {@link JSONRPCNotification}, or {@link JSONRPCResponse} classes.
	 * @throws IOException If there's an error during deserialization
	 * @throws IllegalArgumentException If the JSON structure doesn't match any known
	 * message type
	 */
	public static JSONRPCMessage deserializeJsonRpcMessage(ObjectMapper objectMapper, String jsonText)
			throws IOException {

		logger.debug("Received JSON message: {}", jsonText);

		var map = objectMapper.readValue(jsonText, MAP_TYPE_REF);

		// Determine message type based on specific JSON structure
		if (map.containsKey("method") && map.containsKey("id")) {
			return objectMapper.convertValue(map, JSONRPCRequest.class);
		}
		else if (map.containsKey("method") && !map.containsKey("id")) {
			return objectMapper.convertValue(map, JSONRPCNotification.class);
		}
		else if (map.containsKey("result") || map.containsKey("error")) {
			return objectMapper.convertValue(map, JSONRPCResponse.class);
		}

		throw new IllegalArgumentException("Cannot deserialize JSONRPCMessage: " + jsonText);
	}

	// ---------------------------
	// JSON-RPC Message Types
	// ---------------------------
	public sealed interface JSONRPCMessage permits JSONRPCRequest, JSONRPCNotification, JSONRPCResponse {

		String jsonrpc();

	}

	/**
	 * A request that expects a response.
	 *
	 * @param jsonrpc The JSON-RPC version (must be "2.0")
	 * @param method The name of the method to be invoked
	 * @param id A unique identifier for the request
	 * @param params Parameters for the method call
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	// @JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)
	public record JSONRPCRequest( // @formatter:off
		@JsonProperty("jsonrpc") String jsonrpc,
		@JsonProperty("method") String method,
		@JsonProperty("id") Object id,
		@JsonProperty("params") Object params) implements JSONRPCMessage { // @formatter:on

		/**
		 * Constructor that validates MCP-specific ID requirements. Unlike base JSON-RPC,
		 * MCP requires that: (1) Requests MUST include a string or integer ID; (2) The ID
		 * MUST NOT be null
		 */
		public JSONRPCRequest {
			Assert.notNull(id, "MCP requests MUST include an ID - null IDs are not allowed");
			Assert.isTrue(id instanceof String || id instanceof Integer || id instanceof Long,
					"MCP requests MUST have an ID that is either a string or integer");
		}
	}

	/**
	 * A notification which does not expect a response.
	 *
	 * @param jsonrpc The JSON-RPC version (must be "2.0")
	 * @param method The name of the method being notified
	 * @param params Parameters for the notification
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	// TODO: batching support
	// @JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)
	public record JSONRPCNotification( // @formatter:off
		@JsonProperty("jsonrpc") String jsonrpc,
		@JsonProperty("method") String method,
		@JsonProperty("params") Object params) implements JSONRPCMessage { // @formatter:on
	}

	/**
	 * A successful (non-error) response to a request.
	 *
	 * @param jsonrpc The JSON-RPC version (must be "2.0")
	 * @param id The request identifier that this response corresponds to
	 * @param result The result of the successful request
	 * @param error Error information if the request failed
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	// TODO: batching support
	// @JsonFormat(with = JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY)
	public record JSONRPCResponse( // @formatter:off
		@JsonProperty("jsonrpc") String jsonrpc,
		@JsonProperty("id") Object id,
		@JsonProperty("result") Object result,
		@JsonProperty("error") JSONRPCError error) implements JSONRPCMessage { // @formatter:on

		/**
		 * A response to a request that indicates an error occurred.
		 *
		 * @param code The error type that occurred
		 * @param message A short description of the error. The message SHOULD be limited
		 * to a concise single sentence
		 * @param data Additional information about the error. The value of this member is
		 * defined by the sender (e.g. detailed error information, nested errors etc.)
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		@JsonIgnoreProperties(ignoreUnknown = true)
		public record JSONRPCError( // @formatter:off
			@JsonProperty("code") int code,
			@JsonProperty("message") String message,
			@JsonProperty("data") Object data) { // @formatter:on
		}
	}

	// ---------------------------
	// Initialization
	// ---------------------------
	/**
	 * This request is sent from the client to the server when it first connects, asking
	 * it to begin initialization.
	 *
	 * @param protocolVersion The latest version of the Model Context Protocol that the
	 * client supports. The client MAY decide to support older versions as well
	 * @param capabilities The capabilities that the client supports
	 * @param clientInfo Information about the client implementation
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record InitializeRequest( // @formatter:off
		@JsonProperty("protocolVersion") String protocolVersion,
		@JsonProperty("capabilities") ClientCapabilities capabilities,
		@JsonProperty("clientInfo") Implementation clientInfo,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public InitializeRequest(String protocolVersion, ClientCapabilities capabilities, Implementation clientInfo) {
			this(protocolVersion, capabilities, clientInfo, null);
		}
	}

	/**
	 * After receiving an initialize request from the client, the server sends this
	 * response.
	 *
	 * @param protocolVersion 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
	 * @param capabilities The capabilities that the server supports
	 * @param serverInfo Information about the server implementation
	 * @param instructions Instructions describing how to use the server and its features.
	 * This can be used by clients to improve the LLM's understanding of available tools,
	 * resources, etc. It can be thought of like a "hint" to the model. For example, this
	 * information MAY be added to the system prompt
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record InitializeResult( // @formatter:off
		@JsonProperty("protocolVersion") String protocolVersion,
		@JsonProperty("capabilities") ServerCapabilities capabilities,
		@JsonProperty("serverInfo") Implementation serverInfo,
		@JsonProperty("instructions") String instructions,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public InitializeResult(String protocolVersion, ServerCapabilities capabilities, Implementation serverInfo,
				String instructions) {
			this(protocolVersion, capabilities, serverInfo, instructions, null);
		}
	}

	/**
	 * 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.
	 *
	 * @param experimental Experimental, non-standard capabilities that the client
	 * supports
	 * @param roots Present if the client supports listing roots
	 * @param sampling Present if the client supports sampling from an LLM
	 * @param elicitation Present if the client supports elicitation from the server
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ClientCapabilities( // @formatter:off
		@JsonProperty("experimental") Map<String, Object> experimental,
		@JsonProperty("roots") RootCapabilities roots,
		@JsonProperty("sampling") Sampling sampling,
		@JsonProperty("elicitation") Elicitation elicitation) { // @formatter:on

		/**
		 * Present if the client supports listing roots.
		 *
		 * @param listChanged Whether the client supports notifications for changes to the
		 * roots list
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		@JsonIgnoreProperties(ignoreUnknown = true)
		public record RootCapabilities(@JsonProperty("listChanged") Boolean listChanged) {
		}

		/**
		 * Provides a standardized way for servers to request LLM sampling ("completions"
		 * or "generations") from language models via clients. This flow allows clients to
		 * maintain control over model access, selection, and permissions while enabling
		 * servers to leverage AI capabilities—with no server API keys necessary. Servers
		 * can request text or image-based interactions and optionally include context
		 * from MCP servers in their prompts.
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record Sampling() {
		}

		/**
		 * Provides a standardized way for servers to request additional information from
		 * users through the client during interactions. This flow allows clients to
		 * maintain control over user interactions and data sharing while enabling servers
		 * to gather necessary information dynamically. Servers can request structured
		 * data from users with optional JSON schemas to validate responses.
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record Elicitation() {
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private Map<String, Object> experimental;

			private RootCapabilities roots;

			private Sampling sampling;

			private Elicitation elicitation;

			public Builder experimental(Map<String, Object> experimental) {
				this.experimental = experimental;
				return this;
			}

			public Builder roots(Boolean listChanged) {
				this.roots = new RootCapabilities(listChanged);
				return this;
			}

			public Builder sampling() {
				this.sampling = new Sampling();
				return this;
			}

			public Builder elicitation() {
				this.elicitation = new Elicitation();
				return this;
			}

			public ClientCapabilities build() {
				return new ClientCapabilities(experimental, roots, sampling, elicitation);
			}

		}
	}

	/**
	 * 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.
	 *
	 * @param completions Present if the server supports argument autocompletion
	 * suggestions
	 * @param experimental Experimental, non-standard capabilities that the server
	 * supports
	 * @param logging Present if the server supports sending log messages to the client
	 * @param prompts Present if the server offers any prompt templates
	 * @param resources Present if the server offers any resources to read
	 * @param tools Present if the server offers any tools to call
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ServerCapabilities( // @formatter:off
		@JsonProperty("completions") CompletionCapabilities completions,
		@JsonProperty("experimental") Map<String, Object> experimental,
		@JsonProperty("logging") LoggingCapabilities logging,
		@JsonProperty("prompts") PromptCapabilities prompts,
		@JsonProperty("resources") ResourceCapabilities resources,
		@JsonProperty("tools") ToolCapabilities tools) { // @formatter:on

		/**
		 * Present if the server supports argument autocompletion suggestions.
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record CompletionCapabilities() {
		}

		/**
		 * Present if the server supports sending log messages to the client.
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record LoggingCapabilities() {
		}

		/**
		 * Present if the server offers any prompt templates.
		 *
		 * @param listChanged Whether this server supports notifications for changes to
		 * the prompt list
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record PromptCapabilities(@JsonProperty("listChanged") Boolean listChanged) {
		}

		/**
		 * Present if the server offers any resources to read.
		 *
		 * @param subscribe Whether this server supports subscribing to resource updates
		 * @param listChanged Whether this server supports notifications for changes to
		 * the resource list
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record ResourceCapabilities(@JsonProperty("subscribe") Boolean subscribe,
				@JsonProperty("listChanged") Boolean listChanged) {
		}

		/**
		 * Present if the server offers any tools to call.
		 *
		 * @param listChanged Whether this server supports notifications for changes to
		 * the tool list
		 */
		@JsonInclude(JsonInclude.Include.NON_ABSENT)
		public record ToolCapabilities(@JsonProperty("listChanged") Boolean listChanged) {
		}

		/**
		 * Create a mutated copy of this object with the specified changes.
		 * @return A new Builder instance with the same values as this object.
		 */
		public Builder mutate() {
			var builder = new Builder();
			builder.completions = this.completions;
			builder.experimental = this.experimental;
			builder.logging = this.logging;
			builder.prompts = this.prompts;
			builder.resources = this.resources;
			builder.tools = this.tools;
			return builder;
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private CompletionCapabilities completions;

			private Map<String, Object> experimental;

			private LoggingCapabilities logging;

			private PromptCapabilities prompts;

			private ResourceCapabilities resources;

			private ToolCapabilities tools;

			public Builder completions() {
				this.completions = new CompletionCapabilities();
				return this;
			}

			public Builder experimental(Map<String, Object> experimental) {
				this.experimental = experimental;
				return this;
			}

			public Builder logging() {
				this.logging = new LoggingCapabilities();
				return this;
			}

			public Builder prompts(Boolean listChanged) {
				this.prompts = new PromptCapabilities(listChanged);
				return this;
			}

			public Builder resources(Boolean subscribe, Boolean listChanged) {
				this.resources = new ResourceCapabilities(subscribe, listChanged);
				return this;
			}

			public Builder tools(Boolean listChanged) {
				this.tools = new ToolCapabilities(listChanged);
				return this;
			}

			public ServerCapabilities build() {
				return new ServerCapabilities(completions, experimental, logging, prompts, resources, tools);
			}

		}
	}

	/**
	 * Describes the name and version of an MCP implementation, with an optional title for
	 * UI representation.
	 *
	 * @param name Intended for programmatic or logical use, but used as a display name in
	 * past specs or fallback (if title isn't present).
	 * @param title Intended for UI and end-user contexts
	 * @param version The version of the implementation.
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record Implementation( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("version") String version) implements BaseMetadata { // @formatter:on			

		public Implementation(String name, String version) {
			this(name, null, version);
		}
	}

	// Existing Enums and Base Types (from previous implementation)
	public enum Role {

	// @formatter:off
		@JsonProperty("user") USER,
		@JsonProperty("assistant") ASSISTANT
	} // @formatter:on

	// ---------------------------
	// Resource Interfaces
	// ---------------------------
	/**
	 * Base for objects that include optional annotations for the client. The client can
	 * use annotations to inform how objects are used or displayed
	 */
	public interface Annotated {

		Annotations annotations();

	}

	/**
	 * Optional annotations for the client. The client can use annotations to inform how
	 * objects are used or displayed.
	 *
	 * @param audience Describes who the intended customer of this object or data is. It
	 * can include multiple entries to indicate content useful for multiple audiences
	 * (e.g., `["user", "assistant"]`).
	 * @param priority Describes how important this data is for operating the server. A
	 * value of 1 means "most important," and indicates that the data is effectively
	 * required, while 0 means "least important," and indicates that the data is entirely
	 * optional. It is a number between 0 and 1.
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record Annotations( // @formatter:off
		@JsonProperty("audience") List<Role> audience,
		@JsonProperty("priority") Double priority) { // @formatter:on
	}

	/**
	 * A common interface for resource content, which includes metadata about the resource
	 * such as its URI, name, description, MIME type, size, and annotations. This
	 * interface is implemented by both {@link Resource} and {@link ResourceLink} to
	 * provide a consistent way to access resource metadata.
	 */
	public interface ResourceContent extends BaseMetadata {

		String uri();

		String description();

		String mimeType();

		Long size();

		Annotations annotations();

	}

	/**
	 * Base interface for metadata with name (identifier) and title (display name)
	 * properties.
	 */
	public interface BaseMetadata {

		/**
		 * Intended for programmatic or logical use, but used as a display name in past
		 * specs or fallback (if title isn't present).
		 */
		String name();

		/**
		 * Intended for UI and end-user contexts — optimized to be human-readable and
		 * easily understood, even by those unfamiliar with domain-specific terminology.
		 *
		 * If not provided, the name should be used for display.
		 */
		String title();

	}

	/**
	 * A known resource that the server is capable of reading.
	 *
	 * @param uri the URI of the resource.
	 * @param name A human-readable name for this resource. This can be used by clients to
	 * populate UI elements.
	 * @param title An optional title for this resource.
	 * @param description A description of what this resource represents. This can be used
	 * by clients to improve the LLM's understanding of available resources. It can be
	 * thought of like a "hint" to the model.
	 * @param mimeType The MIME type of this resource, if known.
	 * @param size The size of the raw resource content, in bytes (i.e., before base64
	 * encoding or any tokenization), if known. This can be used by Hosts to display file
	 * sizes and estimate context window usage.
	 * @param annotations Optional annotations for the client. The client can use
	 * annotations to inform how objects are used or displayed.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record Resource( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("description") String description,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("size") Long size,
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, ResourceContent { // @formatter:on

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Resource#builder()} instead.
		 */
		@Deprecated
		public Resource(String uri, String name, String title, String description, String mimeType, Long size,
				Annotations annotations) {
			this(uri, name, title, description, mimeType, size, annotations, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Resource#builder()} instead.
		 */
		@Deprecated
		public Resource(String uri, String name, String description, String mimeType, Long size,
				Annotations annotations) {
			this(uri, name, null, description, mimeType, size, annotations, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Resource#builder()} instead.
		 */
		@Deprecated
		public Resource(String uri, String name, String description, String mimeType, Annotations annotations) {
			this(uri, name, null, description, mimeType, null, annotations, null);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private String uri;

			private String name;

			private String title;

			private String description;

			private String mimeType;

			private Long size;

			private Annotations annotations;

			private Map<String, Object> meta;

			public Builder uri(String uri) {
				this.uri = uri;
				return this;
			}

			public Builder name(String name) {
				this.name = name;
				return this;
			}

			public Builder title(String title) {
				this.title = title;
				return this;
			}

			public Builder description(String description) {
				this.description = description;
				return this;
			}

			public Builder mimeType(String mimeType) {
				this.mimeType = mimeType;
				return this;
			}

			public Builder size(Long size) {
				this.size = size;
				return this;
			}

			public Builder annotations(Annotations annotations) {
				this.annotations = annotations;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public Resource build() {
				Assert.hasText(uri, "uri must not be empty");
				Assert.hasText(name, "name must not be empty");

				return new Resource(uri, name, title, description, mimeType, size, annotations, meta);
			}

		}
	}

	/**
	 * Resource templates allow servers to expose parameterized resources using URI
	 *
	 * @param uriTemplate A URI template that can be used to generate URIs for this
	 * resource.
	 * @param name A human-readable name for this resource. This can be used by clients to
	 * populate UI elements.
	 * @param title An optional title for this resource.
	 * @param description A description of what this resource represents. This can be used
	 * by clients to improve the LLM's understanding of available resources. It can be
	 * thought of like a "hint" to the model.
	 * @param mimeType The MIME type of this resource, if known.
	 * @param annotations Optional annotations for the client. The client can use
	 * annotations to inform how objects are used or displayed.
	 * @see <a href="https://datatracker.ietf.org/doc/html/rfc6570">RFC 6570</a>
	 * @param meta See specification for notes on _meta usage
	 *
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ResourceTemplate( // @formatter:off
		@JsonProperty("uriTemplate") String uriTemplate,
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("description") String description,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, BaseMetadata { // @formatter:on

		public ResourceTemplate(String uriTemplate, String name, String title, String description, String mimeType,
				Annotations annotations) {
			this(uriTemplate, name, title, description, mimeType, annotations, null);
		}

		public ResourceTemplate(String uriTemplate, String name, String description, String mimeType,
				Annotations annotations) {
			this(uriTemplate, name, null, description, mimeType, annotations);
		}
	}

	/**
	 * The server's response to a resources/list request from the client.
	 *
	 * @param resources A list of resources that the server provides
	 * @param nextCursor An opaque token representing the pagination position after the
	 * last returned result. If present, there may be more results available
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ListResourcesResult( // @formatter:off
		@JsonProperty("resources") List<Resource> resources,
		@JsonProperty("nextCursor") String nextCursor,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public ListResourcesResult(List<Resource> resources, String nextCursor) {
			this(resources, nextCursor, null);
		}
	}

	/**
	 * The server's response to a resources/templates/list request from the client.
	 *
	 * @param resourceTemplates A list of resource templates that the server provides
	 * @param nextCursor An opaque token representing the pagination position after the
	 * last returned result. If present, there may be more results available
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ListResourceTemplatesResult( // @formatter:off
		@JsonProperty("resourceTemplates") List<ResourceTemplate> resourceTemplates,
		@JsonProperty("nextCursor") String nextCursor,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public ListResourceTemplatesResult(List<ResourceTemplate> resourceTemplates, String nextCursor) {
			this(resourceTemplates, nextCursor, null);
		}
	}

	/**
	 * Sent from the client to the server, to read a specific resource URI.
	 *
	 * @param uri The URI of the resource to read. The URI can use any protocol; it is up
	 * to the server how to interpret it
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ReadResourceRequest( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public ReadResourceRequest(String uri) {
			this(uri, null);
		}
	}

	/**
	 * The server's response to a resources/read request from the client.
	 *
	 * @param contents The contents of the resource
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ReadResourceResult( // @formatter:off
		@JsonProperty("contents") List<ResourceContents> contents,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public ReadResourceResult(List<ResourceContents> contents) {
			this(contents, null);
		}
	}

	/**
	 * Sent from the client to request resources/updated notifications from the server
	 * whenever a particular resource changes.
	 *
	 * @param uri the URI of the resource to subscribe to. The URI can use any protocol;
	 * it is up to the server how to interpret it.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record SubscribeRequest( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public SubscribeRequest(String uri) {
			this(uri, null);
		}
	}

	/**
	 * Sent from the client to request cancellation of resources/updated notifications
	 * from the server. This should follow a previous resources/subscribe request.
	 *
	 * @param uri The URI of the resource to unsubscribe from
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record UnsubscribeRequest( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public UnsubscribeRequest(String uri) {
			this(uri, null);
		}
	}

	/**
	 * The contents of a specific resource or sub-resource.
	 */
	@JsonTypeInfo(use = JsonTypeInfo.Id.DEDUCTION, include = As.PROPERTY)
	@JsonSubTypes({ @JsonSubTypes.Type(value = TextResourceContents.class, name = "text"),
			@JsonSubTypes.Type(value = BlobResourceContents.class, name = "blob") })
	public sealed interface ResourceContents permits TextResourceContents, BlobResourceContents {

		/**
		 * The URI of this resource.
		 * @return the URI of this resource.
		 */
		String uri();

		/**
		 * The MIME type of this resource.
		 * @return the MIME type of this resource.
		 */
		String mimeType();

		/**
		 * @see <a href=
		 * "https://modelcontextprotocol.io/specification/2025-06-18/basic/index#meta">Specification</a>
		 * for notes on _meta usage
		 * @return additional metadata related to this resource.
		 */
		Map<String, Object> meta();

	}

	/**
	 * Text contents of a resource.
	 *
	 * @param uri the URI of this resource.
	 * @param mimeType the MIME type of this resource.
	 * @param text the text of the resource. This must only be set if the resource can
	 * actually be represented as text (not binary data).
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record TextResourceContents( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("text") String text,
		@JsonProperty("_meta") Map<String, Object> meta) implements ResourceContents { // @formatter:on

		public TextResourceContents(String uri, String mimeType, String text) {
			this(uri, mimeType, text, null);
		}
	}

	/**
	 * Binary contents of a resource.
	 *
	 * @param uri the URI of this resource.
	 * @param mimeType the MIME type of this resource.
	 * @param blob a base64-encoded string representing the binary data of the resource.
	 * This must only be set if the resource can actually be represented as binary data
	 * (not text).
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record BlobResourceContents( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("blob") String blob,
		@JsonProperty("_meta") Map<String, Object> meta) implements ResourceContents { // @formatter:on

		public BlobResourceContents(String uri, String mimeType, String blob) {
			this(uri, mimeType, blob, null);
		}
	}

	// ---------------------------
	// Prompt Interfaces
	// ---------------------------
	/**
	 * A prompt or prompt template that the server offers.
	 *
	 * @param name The name of the prompt or prompt template.
	 * @param title An optional title for the prompt.
	 * @param description An optional description of what this prompt provides.
	 * @param arguments A list of arguments to use for templating the prompt.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record Prompt( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("description") String description,
		@JsonProperty("arguments") List<PromptArgument> arguments,
		@JsonProperty("_meta") Map<String, Object> meta) implements BaseMetadata { // @formatter:on

		public Prompt(String name, String description, List<PromptArgument> arguments) {
			this(name, null, description, arguments != null ? arguments : new ArrayList<>());
		}

		public Prompt(String name, String title, String description, List<PromptArgument> arguments) {
			this(name, title, description, arguments != null ? arguments : new ArrayList<>(), null);
		}
	}

	/**
	 * Describes an argument that a prompt can accept.
	 *
	 * @param name The name of the argument.
	 * @param title An optional title for the argument, which can be used in UI
	 * @param description A human-readable description of the argument.
	 * @param required Whether this argument must be provided.
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record PromptArgument( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("description") String description,
		@JsonProperty("required") Boolean required) implements BaseMetadata { // @formatter:on

		public PromptArgument(String name, String description, Boolean required) {
			this(name, null, description, required);
		}
	}

	/**
	 * Describes a message returned as part of a prompt.
	 *
	 * This is similar to `SamplingMessage`, but also supports the embedding of resources
	 * from the MCP server.
	 *
	 * @param role The sender or recipient of messages and data in a conversation.
	 * @param content The content of the message of type {@link Content}.
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record PromptMessage( // @formatter:off
		@JsonProperty("role") Role role,
		@JsonProperty("content") Content content) { // @formatter:on
	}

	/**
	 * The server's response to a prompts/list request from the client.
	 *
	 * @param prompts A list of prompts that the server provides.
	 * @param nextCursor An optional cursor for pagination. If present, indicates there
	 * are more prompts available.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ListPromptsResult( // @formatter:off
		@JsonProperty("prompts") List<Prompt> prompts,
		@JsonProperty("nextCursor") String nextCursor,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result  { // @formatter:on

		public ListPromptsResult(List<Prompt> prompts, String nextCursor) {
			this(prompts, nextCursor, null);
		}
	}

	/**
	 * Used by the client to get a prompt provided by the server.
	 *
	 * @param name The name of the prompt or prompt template.
	 * @param arguments Arguments to use for templating the prompt.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record GetPromptRequest( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("arguments") Map<String, Object> arguments,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public GetPromptRequest(String name, Map<String, Object> arguments) {
			this(name, arguments, null);
		}
	}

	/**
	 * The server's response to a prompts/get request from the client.
	 *
	 * @param description An optional description for the prompt.
	 * @param messages A list of messages to display as part of the prompt.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record GetPromptResult( // @formatter:off
		@JsonProperty("description") String description,
		@JsonProperty("messages") List<PromptMessage> messages,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public GetPromptResult(String description, List<PromptMessage> messages) {
			this(description, messages, null);
		}
	}

	// ---------------------------
	// Tool Interfaces
	// ---------------------------
	/**
	 * The server's response to a tools/list request from the client.
	 *
	 * @param tools A list of tools that the server provides.
	 * @param nextCursor An optional cursor for pagination. If present, indicates there
	 * are more tools available.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ListToolsResult( // @formatter:off
		@JsonProperty("tools") List<Tool> tools,
		@JsonProperty("nextCursor") String nextCursor,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public ListToolsResult(List<Tool> tools, String nextCursor) {
			this(tools, nextCursor, null);
		}
	}

	/**
	 * A JSON Schema object that describes the expected structure of arguments or output.
	 *
	 * @param type The type of the schema (e.g., "object")
	 * @param properties The properties of the schema object
	 * @param required List of required property names
	 * @param additionalProperties Whether additional properties are allowed
	 * @param defs Schema definitions using the newer $defs keyword
	 * @param definitions Schema definitions using the legacy definitions keyword
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record JsonSchema( // @formatter:off
		@JsonProperty("type") String type,
		@JsonProperty("properties") Map<String, Object> properties,
		@JsonProperty("required") List<String> required,
		@JsonProperty("additionalProperties") Boolean additionalProperties,
		@JsonProperty("$defs") Map<String, Object> defs,
		@JsonProperty("definitions") Map<String, Object> definitions) { // @formatter:on
	}

	/**
	 * Additional properties describing a Tool to clients.
	 *
	 * NOTE: all properties in ToolAnnotations are **hints**. They are not guaranteed to
	 * provide a faithful description of tool behavior (including descriptive properties
	 * like `title`).
	 *
	 * Clients should never make tool use decisions based on ToolAnnotations received from
	 * untrusted servers.
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ToolAnnotations( // @formatter:off
		@JsonProperty("title")  String title,
		@JsonProperty("readOnlyHint")   Boolean readOnlyHint,
		@JsonProperty("destructiveHint") Boolean destructiveHint,
		@JsonProperty("idempotentHint") Boolean idempotentHint,
		@JsonProperty("openWorldHint") Boolean openWorldHint,
		@JsonProperty("returnDirect") Boolean returnDirect) { // @formatter:on
	}

	/**
	 * Represents a tool that the server provides. Tools enable servers to expose
	 * executable functionality to the system. Through these tools, you can interact with
	 * external systems, perform computations, and take actions in the real world.
	 *
	 * @param name A unique identifier for the tool. This name is used when calling the
	 * tool.
	 * @param title A human-readable title for the tool.
	 * @param description A human-readable description of what the tool does. This can be
	 * used by clients to improve the LLM's understanding of available tools.
	 * @param inputSchema A JSON Schema object that describes the expected structure of
	 * the arguments when calling this tool. This allows clients to validate tool
	 * @param outputSchema An optional JSON Schema object defining the structure of the
	 * tool's output returned in the structuredContent field of a CallToolResult.
	 * @param annotations Optional additional tool information.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record Tool( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("description") String description,
		@JsonProperty("inputSchema") JsonSchema inputSchema,
		@JsonProperty("outputSchema") Map<String, Object> outputSchema,
		@JsonProperty("annotations") ToolAnnotations annotations,
		@JsonProperty("_meta") Map<String, Object> meta) { // @formatter:on

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Tool#builder()} instead.
		 */
		@Deprecated
		public Tool(String name, String description, JsonSchema inputSchema, ToolAnnotations annotations) {
			this(name, null, description, inputSchema, null, annotations, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Tool#builder()} instead.
		 */
		@Deprecated
		public Tool(String name, String description, String inputSchema) {
			this(name, null, description, parseSchema(inputSchema), null, null, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Tool#builder()} instead.
		 */
		@Deprecated
		public Tool(String name, String description, String schema, ToolAnnotations annotations) {
			this(name, null, description, parseSchema(schema), null, annotations, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Tool#builder()} instead.
		 */
		@Deprecated
		public Tool(String name, String description, String inputSchema, String outputSchema,
				ToolAnnotations annotations) {
			this(name, null, description, parseSchema(inputSchema), schemaToMap(outputSchema), annotations, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link Tool#builder()} instead.
		 */
		@Deprecated
		public Tool(String name, String title, String description, String inputSchema, String outputSchema,
				ToolAnnotations annotations) {
			this(name, title, description, parseSchema(inputSchema), schemaToMap(outputSchema), annotations, null);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private String name;

			private String title;

			private String description;

			private JsonSchema inputSchema;

			private Map<String, Object> outputSchema;

			private ToolAnnotations annotations;

			private Map<String, Object> meta;

			public Builder name(String name) {
				this.name = name;
				return this;
			}

			public Builder title(String title) {
				this.title = title;
				return this;
			}

			public Builder description(String description) {
				this.description = description;
				return this;
			}

			public Builder inputSchema(JsonSchema inputSchema) {
				this.inputSchema = inputSchema;
				return this;
			}

			public Builder inputSchema(String inputSchema) {
				this.inputSchema = parseSchema(inputSchema);
				return this;
			}

			public Builder outputSchema(Map<String, Object> outputSchema) {
				this.outputSchema = outputSchema;
				return this;
			}

			public Builder outputSchema(String outputSchema) {
				this.outputSchema = schemaToMap(outputSchema);
				return this;
			}

			public Builder annotations(ToolAnnotations annotations) {
				this.annotations = annotations;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public Tool build() {
				Assert.hasText(name, "name must not be empty");
				return new Tool(name, title, description, inputSchema, outputSchema, annotations, meta);
			}

		}
	}

	private static Map<String, Object> schemaToMap(String schema) {
		try {
			return OBJECT_MAPPER.readValue(schema, MAP_TYPE_REF);
		}
		catch (IOException e) {
			throw new IllegalArgumentException("Invalid schema: " + schema, e);
		}
	}

	private static JsonSchema parseSchema(String schema) {
		try {
			return OBJECT_MAPPER.readValue(schema, JsonSchema.class);
		}
		catch (IOException e) {
			throw new IllegalArgumentException("Invalid schema: " + schema, e);
		}
	}

	/**
	 * Used by the client to call a tool provided by the server.
	 *
	 * @param name The name of the tool to call. This must match a tool name from
	 * tools/list.
	 * @param arguments Arguments to pass to the tool. These must conform to the tool's
	 * input schema.
	 * @param meta Optional metadata about the request. This can include additional
	 * information like `progressToken`
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record CallToolRequest( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("arguments") Map<String, Object> arguments,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public CallToolRequest(String name, String jsonArguments) {
			this(name, parseJsonArguments(jsonArguments), null);
		}

		public CallToolRequest(String name, Map<String, Object> arguments) {
			this(name, arguments, null);
		}

		private static Map<String, Object> parseJsonArguments(String jsonArguments) {
			try {
				return OBJECT_MAPPER.readValue(jsonArguments, MAP_TYPE_REF);
			}
			catch (IOException e) {
				throw new IllegalArgumentException("Invalid arguments: " + jsonArguments, e);
			}
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private String name;

			private Map<String, Object> arguments;

			private Map<String, Object> meta;

			public Builder name(String name) {
				this.name = name;
				return this;
			}

			public Builder arguments(Map<String, Object> arguments) {
				this.arguments = arguments;
				return this;
			}

			public Builder arguments(String jsonArguments) {
				this.arguments = parseJsonArguments(jsonArguments);
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public Builder progressToken(String progressToken) {
				if (this.meta == null) {
					this.meta = new HashMap<>();
				}
				this.meta.put("progressToken", progressToken);
				return this;
			}

			public CallToolRequest build() {
				Assert.hasText(name, "name must not be empty");
				return new CallToolRequest(name, arguments, meta);
			}

		}
	}

	/**
	 * The server's response to a tools/call request from the client.
	 *
	 * @param content A list of content items representing the tool's output. Each item
	 * can be text, an image, or an embedded resource.
	 * @param isError If true, indicates that the tool execution failed and the content
	 * contains error information. If false or absent, indicates successful execution.
	 * @param structuredContent An optional JSON object that represents the structured
	 * result of the tool call.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record CallToolResult( // @formatter:off
		@JsonProperty("content") List<Content> content,
		@JsonProperty("isError") Boolean isError,
		@JsonProperty("structuredContent") Map<String, Object> structuredContent,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		// backwards compatibility constructor
		public CallToolResult(List<Content> content, Boolean isError) {
			this(content, isError, null, null);
		}

		// backwards compatibility constructor
		public CallToolResult(List<Content> content, Boolean isError, Map<String, Object> structuredContent) {
			this(content, isError, structuredContent, null);
		}

		/**
		 * Creates a new instance of {@link CallToolResult} with a string containing the
		 * tool result.
		 * @param content The content of the tool result. This will be mapped to a
		 * one-sized list with a {@link TextContent} element.
		 * @param isError If true, indicates that the tool execution failed and the
		 * content contains error information. If false or absent, indicates successful
		 * execution.
		 */
		public CallToolResult(String content, Boolean isError) {
			this(List.of(new TextContent(content)), isError, null);
		}

		/**
		 * Creates a builder for {@link CallToolResult}.
		 * @return a new builder instance
		 */
		public static Builder builder() {
			return new Builder();
		}

		/**
		 * Builder for {@link CallToolResult}.
		 */
		public static class Builder {

			private List<Content> content = new ArrayList<>();

			private Boolean isError = false;

			private Map<String, Object> structuredContent;

			private Map<String, Object> meta;

			/**
			 * Sets the content list for the tool result.
			 * @param content the content list
			 * @return this builder
			 */
			public Builder content(List<Content> content) {
				Assert.notNull(content, "content must not be null");
				this.content = content;
				return this;
			}

			public Builder structuredContent(Map<String, Object> structuredContent) {
				Assert.notNull(structuredContent, "structuredContent must not be null");
				this.structuredContent = structuredContent;
				return this;
			}

			public Builder structuredContent(String structuredContent) {
				Assert.hasText(structuredContent, "structuredContent must not be empty");
				try {
					this.structuredContent = OBJECT_MAPPER.readValue(structuredContent, MAP_TYPE_REF);
				}
				catch (IOException e) {
					throw new IllegalArgumentException("Invalid structured content: " + structuredContent, e);
				}
				return this;
			}

			/**
			 * Sets the text content for the tool result.
			 * @param textContent the text content
			 * @return this builder
			 */
			public Builder textContent(List<String> textContent) {
				Assert.notNull(textContent, "textContent must not be null");
				textContent.stream().map(TextContent::new).forEach(this.content::add);
				return this;
			}

			/**
			 * Adds a content item to the tool result.
			 * @param contentItem the content item to add
			 * @return this builder
			 */
			public Builder addContent(Content contentItem) {
				Assert.notNull(contentItem, "contentItem must not be null");
				if (this.content == null) {
					this.content = new ArrayList<>();
				}
				this.content.add(contentItem);
				return this;
			}

			/**
			 * Adds a text content item to the tool result.
			 * @param text the text content
			 * @return this builder
			 */
			public Builder addTextContent(String text) {
				Assert.notNull(text, "text must not be null");
				return addContent(new TextContent(text));
			}

			/**
			 * Sets whether the tool execution resulted in an error.
			 * @param isError true if the tool execution failed, false otherwise
			 * @return this builder
			 */
			public Builder isError(Boolean isError) {
				Assert.notNull(isError, "isError must not be null");
				this.isError = isError;
				return this;
			}

			/**
			 * Sets the metadata for the tool result.
			 * @param meta metadata
			 * @return this builder
			 */
			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			/**
			 * Builds a new {@link CallToolResult} instance.
			 * @return a new CallToolResult instance
			 */
			public CallToolResult build() {
				return new CallToolResult(content, isError, structuredContent, meta);
			}

		}

	}

	// ---------------------------
	// Sampling Interfaces
	// ---------------------------
	/**
	 * The server's preferences for model selection, requested of the client during
	 * sampling.
	 *
	 * @param hints Optional hints to use for model selection. If multiple hints are
	 * specified, the client MUST evaluate them in order (such that the first match is
	 * taken). The client SHOULD prioritize these hints over the numeric priorities, but
	 * MAY still use the priorities to select from ambiguous matches
	 * @param costPriority How much to prioritize cost when selecting a model. A value of
	 * 0 means cost is not important, while a value of 1 means cost is the most important
	 * factor
	 * @param speedPriority How much to prioritize sampling speed (latency) when selecting
	 * a model. A value of 0 means speed is not important, while a value of 1 means speed
	 * is the most important factor
	 * @param intelligencePriority How much to prioritize intelligence and capabilities
	 * when selecting a model. A value of 0 means intelligence is not important, while a
	 * value of 1 means intelligence is the most important factor
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ModelPreferences( // @formatter:off
		@JsonProperty("hints") List<ModelHint> hints,
		@JsonProperty("costPriority") Double costPriority,
		@JsonProperty("speedPriority") Double speedPriority,
		@JsonProperty("intelligencePriority") Double intelligencePriority) { // @formatter:on

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private List<ModelHint> hints;

			private Double costPriority;

			private Double speedPriority;

			private Double intelligencePriority;

			public Builder hints(List<ModelHint> hints) {
				this.hints = hints;
				return this;
			}

			public Builder addHint(String name) {
				if (this.hints == null) {
					this.hints = new ArrayList<>();
				}
				this.hints.add(new ModelHint(name));
				return this;
			}

			public Builder costPriority(Double costPriority) {
				this.costPriority = costPriority;
				return this;
			}

			public Builder speedPriority(Double speedPriority) {
				this.speedPriority = speedPriority;
				return this;
			}

			public Builder intelligencePriority(Double intelligencePriority) {
				this.intelligencePriority = intelligencePriority;
				return this;
			}

			public ModelPreferences build() {
				return new ModelPreferences(hints, costPriority, speedPriority, intelligencePriority);
			}

		}
	}

	/**
	 * Hints to use for model selection.
	 *
	 * @param name A hint for a model name. The client SHOULD treat this as a substring of
	 * a model name; for example: `claude-3-5-sonnet` should match
	 * `claude-3-5-sonnet-20241022`, `sonnet` should match `claude-3-5-sonnet-20241022`,
	 * `claude-3-sonnet-20240229`, etc., `claude` should match any Claude model. The
	 * client MAY also map the string to a different provider's model name or a different
	 * model family, as long as it fills a similar niche
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ModelHint(@JsonProperty("name") String name) {
		public static ModelHint of(String name) {
			return new ModelHint(name);
		}
	}

	/**
	 * Describes a message issued to or received from an LLM API.
	 *
	 * @param role The sender or recipient of messages and data in a conversation
	 * @param content The content of the message
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record SamplingMessage( // @formatter:off
		@JsonProperty("role") Role role,
		@JsonProperty("content") Content content) { // @formatter:on
	}

	/**
	 * A request from the server to sample an LLM via the client. The client has full
	 * discretion over which model to select. The client should also inform the user
	 * before beginning sampling, to allow them to inspect the request (human in the loop)
	 * and decide whether to approve it.
	 *
	 * @param messages The conversation messages to send to the LLM
	 * @param modelPreferences The server's preferences for which model to select. The
	 * client MAY ignore these preferences
	 * @param systemPrompt An optional system prompt the server wants to use for sampling.
	 * The client MAY modify or omit this prompt
	 * @param includeContext 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
	 * @param temperature Optional temperature parameter for sampling
	 * @param maxTokens The maximum number of tokens to sample, as requested by the
	 * server. The client MAY choose to sample fewer tokens than requested
	 * @param stopSequences Optional stop sequences for sampling
	 * @param metadata Optional metadata to pass through to the LLM provider. The format
	 * of this metadata is provider-specific
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record CreateMessageRequest( // @formatter:off
		@JsonProperty("messages") List<SamplingMessage> messages,
		@JsonProperty("modelPreferences") ModelPreferences modelPreferences,
		@JsonProperty("systemPrompt") String systemPrompt,
		@JsonProperty("includeContext") ContextInclusionStrategy includeContext,
		@JsonProperty("temperature") Double temperature,
		@JsonProperty("maxTokens") int maxTokens,
		@JsonProperty("stopSequences") List<String> stopSequences,
		@JsonProperty("metadata") Map<String, Object> metadata,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		// backwards compatibility constructor
		public CreateMessageRequest(List<SamplingMessage> messages, ModelPreferences modelPreferences,
				String systemPrompt, ContextInclusionStrategy includeContext, Double temperature, int maxTokens,
				List<String> stopSequences, Map<String, Object> metadata) {
			this(messages, modelPreferences, systemPrompt, includeContext, temperature, maxTokens, stopSequences,
					metadata, null);
		}

		public enum ContextInclusionStrategy {

		// @formatter:off
			@JsonProperty("none") NONE,
			@JsonProperty("thisServer") THIS_SERVER,
			@JsonProperty("allServers")ALL_SERVERS
		} // @formatter:on

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private List<SamplingMessage> messages;

			private ModelPreferences modelPreferences;

			private String systemPrompt;

			private ContextInclusionStrategy includeContext;

			private Double temperature;

			private int maxTokens;

			private List<String> stopSequences;

			private Map<String, Object> metadata;

			private Map<String, Object> meta;

			public Builder messages(List<SamplingMessage> messages) {
				this.messages = messages;
				return this;
			}

			public Builder modelPreferences(ModelPreferences modelPreferences) {
				this.modelPreferences = modelPreferences;
				return this;
			}

			public Builder systemPrompt(String systemPrompt) {
				this.systemPrompt = systemPrompt;
				return this;
			}

			public Builder includeContext(ContextInclusionStrategy includeContext) {
				this.includeContext = includeContext;
				return this;
			}

			public Builder temperature(Double temperature) {
				this.temperature = temperature;
				return this;
			}

			public Builder maxTokens(int maxTokens) {
				this.maxTokens = maxTokens;
				return this;
			}

			public Builder stopSequences(List<String> stopSequences) {
				this.stopSequences = stopSequences;
				return this;
			}

			public Builder metadata(Map<String, Object> metadata) {
				this.metadata = metadata;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public Builder progressToken(String progressToken) {
				if (this.meta == null) {
					this.meta = new HashMap<>();
				}
				this.meta.put("progressToken", progressToken);
				return this;
			}

			public CreateMessageRequest build() {
				return new CreateMessageRequest(messages, modelPreferences, systemPrompt, includeContext, temperature,
						maxTokens, stopSequences, metadata, meta);
			}

		}
	}

	/**
	 * The client's response to a sampling/create_message request from the server. The
	 * client should inform the user before returning the sampled message, to allow them
	 * to inspect the response (human in the loop) and decide whether to allow the server
	 * to see it.
	 *
	 * @param role The role of the message sender (typically assistant)
	 * @param content The content of the sampled message
	 * @param model The name of the model that generated the message
	 * @param stopReason The reason why sampling stopped, if known
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record CreateMessageResult( // @formatter:off
		@JsonProperty("role") Role role,
		@JsonProperty("content") Content content,
		@JsonProperty("model") String model,
		@JsonProperty("stopReason") StopReason stopReason,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public enum StopReason {

		// @formatter:off
			@JsonProperty("endTurn") END_TURN("endTurn"),
			@JsonProperty("stopSequence") STOP_SEQUENCE("stopSequence"),
			@JsonProperty("maxTokens") MAX_TOKENS("maxTokens"),
			@JsonProperty("unknown") UNKNOWN("unknown");
			// @formatter:on

			private final String value;

			StopReason(String value) {
				this.value = value;
			}

			@JsonCreator
			private static StopReason of(String value) {
				return Arrays.stream(StopReason.values())
					.filter(stopReason -> stopReason.value.equals(value))
					.findFirst()
					.orElse(StopReason.UNKNOWN);
			}

		}

		public CreateMessageResult(Role role, Content content, String model, StopReason stopReason) {
			this(role, content, model, stopReason, null);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private Role role = Role.ASSISTANT;

			private Content content;

			private String model;

			private StopReason stopReason = StopReason.END_TURN;

			private Map<String, Object> meta;

			public Builder role(Role role) {
				this.role = role;
				return this;
			}

			public Builder content(Content content) {
				this.content = content;
				return this;
			}

			public Builder model(String model) {
				this.model = model;
				return this;
			}

			public Builder stopReason(StopReason stopReason) {
				this.stopReason = stopReason;
				return this;
			}

			public Builder message(String message) {
				this.content = new TextContent(message);
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public CreateMessageResult build() {
				return new CreateMessageResult(role, content, model, stopReason, meta);
			}

		}
	}

	// Elicitation
	/**
	 * A request from the server to elicit additional information from the user via the
	 * client.
	 *
	 * @param message The message to present to the user
	 * @param requestedSchema A restricted subset of JSON Schema. Only top-level
	 * properties are allowed, without nesting
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ElicitRequest( // @formatter:off
		@JsonProperty("message") String message,
		@JsonProperty("requestedSchema") Map<String, Object> requestedSchema,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		// backwards compatibility constructor
		public ElicitRequest(String message, Map<String, Object> requestedSchema) {
			this(message, requestedSchema, null);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private String message;

			private Map<String, Object> requestedSchema;

			private Map<String, Object> meta;

			public Builder message(String message) {
				this.message = message;
				return this;
			}

			public Builder requestedSchema(Map<String, Object> requestedSchema) {
				this.requestedSchema = requestedSchema;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public Builder progressToken(String progressToken) {
				if (this.meta == null) {
					this.meta = new HashMap<>();
				}
				this.meta.put("progressToken", progressToken);
				return this;
			}

			public ElicitRequest build() {
				return new ElicitRequest(message, requestedSchema, meta);
			}

		}
	}

	/**
	 * The client's response to an elicitation request.
	 *
	 * @param action The user action in response to the elicitation. "accept": User
	 * submitted the form/confirmed the action, "decline": User explicitly declined the
	 * action, "cancel": User dismissed without making an explicit choice
	 * @param content The submitted form data, only present when action is "accept".
	 * Contains values matching the requested schema
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ElicitResult( // @formatter:off
		@JsonProperty("action") Action action,
		@JsonProperty("content") Map<String, Object> content,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public enum Action {

		// @formatter:off
			@JsonProperty("accept") ACCEPT,
			@JsonProperty("decline") DECLINE,
			@JsonProperty("cancel") CANCEL
		} // @formatter:on

		// backwards compatibility constructor
		public ElicitResult(Action action, Map<String, Object> content) {
			this(action, content, null);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private Action action;

			private Map<String, Object> content;

			private Map<String, Object> meta;

			public Builder message(Action action) {
				this.action = action;
				return this;
			}

			public Builder content(Map<String, Object> content) {
				this.content = content;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public ElicitResult build() {
				return new ElicitResult(action, content, meta);
			}

		}
	}

	// ---------------------------
	// Pagination Interfaces
	// ---------------------------
	/**
	 * A request that supports pagination using cursors.
	 *
	 * @param cursor An opaque token representing the current pagination position. If
	 * provided, the server should return results starting after this cursor
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record PaginatedRequest( // @formatter:off
		@JsonProperty("cursor") String cursor,
		@JsonProperty("_meta") Map<String, Object> meta) implements Request { // @formatter:on

		public PaginatedRequest(String cursor) {
			this(cursor, null);
		}

		/**
		 * Creates a new paginated request with an empty cursor.
		 */
		public PaginatedRequest() {
			this(null);
		}
	}

	/**
	 * An opaque token representing the pagination position after the last returned
	 * result. If present, there may be more results available.
	 *
	 * @param nextCursor An opaque token representing the pagination position after the
	 * last returned result. If present, there may be more results available
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record PaginatedResult(@JsonProperty("nextCursor") String nextCursor) {
	}

	// ---------------------------
	// Progress and Logging
	// ---------------------------
	/**
	 * The Model Context Protocol (MCP) supports optional progress tracking for
	 * long-running operations through notification messages. Either side can send
	 * progress notifications to provide updates about operation status.
	 *
	 * @param progressToken A unique token to identify the progress notification. MUST be
	 * unique across all active requests.
	 * @param progress A value indicating the current progress.
	 * @param total An optional total amount of work to be done, if known.
	 * @param message An optional message providing additional context about the progress.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ProgressNotification( // @formatter:off
		@JsonProperty("progressToken") String progressToken,
		@JsonProperty("progress") Double progress,
		@JsonProperty("total") Double total,
		@JsonProperty("message") String message,
		@JsonProperty("_meta") Map<String, Object> meta) implements Notification { // @formatter:on

		public ProgressNotification(String progressToken, double progress, Double total, String message) {
			this(progressToken, progress, total, message, null);
		}
	}

	/**
	 * The Model Context Protocol (MCP) provides a standardized way for servers to send
	 * resources update message to clients.
	 *
	 * @param uri The updated resource uri.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ResourcesUpdatedNotification(// @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("_meta") Map<String, Object> meta) implements Notification { // @formatter:on

		public ResourcesUpdatedNotification(String uri) {
			this(uri, null);
		}
	}

	/**
	 * The Model Context Protocol (MCP) provides a standardized way for servers to send
	 * structured log messages to clients. Clients can control logging verbosity by
	 * setting minimum log levels, with servers sending notifications containing severity
	 * levels, optional logger names, and arbitrary JSON-serializable data.
	 *
	 * @param level The severity levels. The minimum log level is set by the client.
	 * @param logger The logger that generated the message.
	 * @param data JSON-serializable logging data.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record LoggingMessageNotification( // @formatter:off
		@JsonProperty("level") LoggingLevel level,
		@JsonProperty("logger") String logger,
		@JsonProperty("data") String data,
		@JsonProperty("_meta") Map<String, Object> meta) implements Notification { // @formatter:on

		// backwards compatibility constructor
		public LoggingMessageNotification(LoggingLevel level, String logger, String data) {
			this(level, logger, data, null);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private LoggingLevel level = LoggingLevel.INFO;

			private String logger = "server";

			private String data;

			private Map<String, Object> meta;

			public Builder level(LoggingLevel level) {
				this.level = level;
				return this;
			}

			public Builder logger(String logger) {
				this.logger = logger;
				return this;
			}

			public Builder data(String data) {
				this.data = data;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public LoggingMessageNotification build() {
				return new LoggingMessageNotification(level, logger, data, meta);
			}

		}
	}

	public enum LoggingLevel {

	// @formatter:off
		@JsonProperty("debug") DEBUG(0),
		@JsonProperty("info") INFO(1),
		@JsonProperty("notice") NOTICE(2),
		@JsonProperty("warning") WARNING(3),
		@JsonProperty("error") ERROR(4),
		@JsonProperty("critical") CRITICAL(5),
		@JsonProperty("alert") ALERT(6),
		@JsonProperty("emergency") EMERGENCY(7);
		// @formatter:on

		private final int level;

		LoggingLevel(int level) {
			this.level = level;
		}

		public int level() {
			return level;
		}

	}

	/**
	 * A request from the client to the server, to enable or adjust logging.
	 *
	 * @param level 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 notifications/message
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record SetLevelRequest(@JsonProperty("level") LoggingLevel level) {
	}

	// ---------------------------
	// Autocomplete
	// ---------------------------
	public sealed interface CompleteReference permits PromptReference, ResourceReference {

		String type();

		String identifier();

	}

	/**
	 * Identifies a prompt for completion requests.
	 *
	 * @param type The reference type identifier (typically "ref/prompt")
	 * @param name The name of the prompt
	 * @param title An optional title for the prompt
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record PromptReference( // @formatter:off
		@JsonProperty("type") String type,
		@JsonProperty("name") String name,
		@JsonProperty("title") String title ) implements McpSchema.CompleteReference, BaseMetadata { // @formatter:on

		public PromptReference(String type, String name) {
			this(type, name, null);
		}

		public PromptReference(String name) {
			this("ref/prompt", name, null);
		}

		@Override
		public String identifier() {
			return name();
		}

		@Override
		public boolean equals(Object obj) {
			if (this == obj)
				return true;
			if (obj == null || getClass() != obj.getClass())
				return false;
			PromptReference that = (PromptReference) obj;
			return java.util.Objects.equals(identifier(), that.identifier())
					&& java.util.Objects.equals(type(), that.type());
		}

		@Override
		public int hashCode() {
			return java.util.Objects.hash(identifier(), type());
		}
	}

	/**
	 * A reference to a resource or resource template definition for completion requests.
	 *
	 * @param type The reference type identifier (typically "ref/resource")
	 * @param uri The URI or URI template of the resource
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ResourceReference( // @formatter:off
		@JsonProperty("type") String type,
		@JsonProperty("uri") String uri) implements McpSchema.CompleteReference { // @formatter:on

		public ResourceReference(String uri) {
			this("ref/resource", uri);
		}

		@Override
		public String identifier() {
			return uri();
		}
	}

	/**
	 * A request from the client to the server, to ask for completion options.
	 *
	 * @param ref A reference to a prompt or resource template definition
	 * @param argument The argument's information for completion requests
	 * @param meta See specification for notes on _meta usage
	 * @param context Additional, optional context for completions
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record CompleteRequest( // @formatter:off
		@JsonProperty("ref") McpSchema.CompleteReference ref,
		@JsonProperty("argument") CompleteArgument argument,
		@JsonProperty("_meta") Map<String, Object> meta,
		@JsonProperty("context") CompleteContext context) implements Request { // @formatter:on

		public CompleteRequest(McpSchema.CompleteReference ref, CompleteArgument argument, Map<String, Object> meta) {
			this(ref, argument, meta, null);
		}

		public CompleteRequest(McpSchema.CompleteReference ref, CompleteArgument argument, CompleteContext context) {
			this(ref, argument, null, context);
		}

		public CompleteRequest(McpSchema.CompleteReference ref, CompleteArgument argument) {
			this(ref, argument, null, null);
		}

		/**
		 * The argument's information for completion requests.
		 *
		 * @param name The name of the argument
		 * @param value The value of the argument to use for completion matching
		 */
		public record CompleteArgument(@JsonProperty("name") String name, @JsonProperty("value") String value) {
		}

		/**
		 * Additional, optional context for completions.
		 *
		 * @param arguments Previously-resolved variables in a URI template or prompt
		 */
		public record CompleteContext(@JsonProperty("arguments") Map<String, String> arguments) {
		}
	}

	/**
	 * The server's response to a completion/complete request.
	 *
	 * @param completion The completion information containing values and metadata
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record CompleteResult(@JsonProperty("completion") CompleteCompletion completion,
			@JsonProperty("_meta") Map<String, Object> meta) implements Result {

		// backwards compatibility constructor
		public CompleteResult(CompleteCompletion completion) {
			this(completion, null);
		}

		/**
		 * The server's response to a completion/complete request
		 *
		 * @param values An array of completion values. Must not exceed 100 items
		 * @param total The total number of completion options available. This can exceed
		 * the number of values actually sent in the response
		 * @param hasMore Indicates whether there are additional completion options beyond
		 * those provided in the current response, even if the exact total is unknown
		 */
		public record CompleteCompletion( // @formatter:off
				@JsonProperty("values") List<String> values,
				@JsonProperty("total") Integer total,
				@JsonProperty("hasMore") Boolean hasMore) { // @formatter:on
		}
	}

	// ---------------------------
	// Content Types
	// ---------------------------
	@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "type")
	@JsonSubTypes({ @JsonSubTypes.Type(value = TextContent.class, name = "text"),
			@JsonSubTypes.Type(value = ImageContent.class, name = "image"),
			@JsonSubTypes.Type(value = AudioContent.class, name = "audio"),
			@JsonSubTypes.Type(value = EmbeddedResource.class, name = "resource"),
			@JsonSubTypes.Type(value = ResourceLink.class, name = "resource_link") })
	public sealed interface Content permits TextContent, ImageContent, AudioContent, EmbeddedResource, ResourceLink {

		Map<String, Object> meta();

		default String type() {
			if (this instanceof TextContent) {
				return "text";
			}
			else if (this instanceof ImageContent) {
				return "image";
			}
			else if (this instanceof AudioContent) {
				return "audio";
			}
			else if (this instanceof EmbeddedResource) {
				return "resource";
			}
			else if (this instanceof ResourceLink) {
				return "resource_link";
			}
			throw new IllegalArgumentException("Unknown content type: " + this);
		}

	}

	/**
	 * Text provided to or from an LLM.
	 *
	 * @param annotations Optional annotations for the client
	 * @param text The text content of the message
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record TextContent( // @formatter:off
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("text") String text,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, Content { // @formatter:on

		public TextContent(Annotations annotations, String text) {
			this(annotations, text, null);
		}

		public TextContent(String content) {
			this(null, content, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link TextContent#TextContent(Annotations, String)} instead.
		 */
		@Deprecated
		public TextContent(List<Role> audience, Double priority, String content) {
			this(audience != null || priority != null ? new Annotations(audience, priority) : null, content, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link TextContent#annotations()} instead.
		 */
		@Deprecated
		public List<Role> audience() {
			return annotations == null ? null : annotations.audience();
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link TextContent#annotations()} instead.
		 */
		@Deprecated
		public Double priority() {
			return annotations == null ? null : annotations.priority();
		}
	}

	/**
	 * An image provided to or from an LLM.
	 *
	 * @param annotations Optional annotations for the client
	 * @param data The base64-encoded image data
	 * @param mimeType The MIME type of the image. Different providers may support
	 * different image types
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ImageContent( // @formatter:off
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("data") String data,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, Content { // @formatter:on

		public ImageContent(Annotations annotations, String data, String mimeType) {
			this(annotations, data, mimeType, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link ImageContent#ImageContent(Annotations, String, String)} instead.
		 */
		@Deprecated
		public ImageContent(List<Role> audience, Double priority, String data, String mimeType) {
			this(audience != null || priority != null ? new Annotations(audience, priority) : null, data, mimeType,
					null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link ImageContent#annotations()} instead.
		 */
		@Deprecated
		public List<Role> audience() {
			return annotations == null ? null : annotations.audience();
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link ImageContent#annotations()} instead.
		 */
		@Deprecated
		public Double priority() {
			return annotations == null ? null : annotations.priority();
		}
	}

	/**
	 * Audio provided to or from an LLM.
	 *
	 * @param annotations Optional annotations for the client
	 * @param data The base64-encoded audio data
	 * @param mimeType The MIME type of the audio. Different providers may support
	 * different audio types
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record AudioContent( // @formatter:off
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("data") String data,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, Content { // @formatter:on

		// backwards compatibility constructor
		public AudioContent(Annotations annotations, String data, String mimeType) {
			this(annotations, data, mimeType, null);
		}
	}

	/**
	 * The contents of a resource, embedded into a prompt or tool call result.
	 *
	 * It is up to the client how best to render embedded resources for the benefit of the
	 * LLM and/or the user.
	 *
	 * @param annotations Optional annotations for the client
	 * @param resource The resource contents that are embedded
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record EmbeddedResource( // @formatter:off
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("resource") ResourceContents resource,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, Content { // @formatter:on

		// backwards compatibility constructor
		public EmbeddedResource(Annotations annotations, ResourceContents resource) {
			this(annotations, resource, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link EmbeddedResource#EmbeddedResource(Annotations, ResourceContents)}
		 * instead.
		 */
		@Deprecated
		public EmbeddedResource(List<Role> audience, Double priority, ResourceContents resource) {
			this(audience != null || priority != null ? new Annotations(audience, priority) : null, resource, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link EmbeddedResource#annotations()} instead.
		 */
		@Deprecated
		public List<Role> audience() {
			return annotations == null ? null : annotations.audience();
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link EmbeddedResource#annotations()} instead.
		 */
		@Deprecated
		public Double priority() {
			return annotations == null ? null : annotations.priority();
		}
	}

	/**
	 * A known resource that the server is capable of reading.
	 *
	 * @param uri the URI of the resource.
	 * @param name A human-readable name for this resource. This can be used by clients to
	 * populate UI elements.
	 * @param title A human-readable title for this resource.
	 * @param description A description of what this resource represents. This can be used
	 * by clients to improve the LLM's understanding of available resources. It can be
	 * thought of like a "hint" to the model.
	 * @param mimeType The MIME type of this resource, if known.
	 * @param size The size of the raw resource content, in bytes (i.e., before base64
	 * encoding or any tokenization), if known. This can be used by Hosts to display file
	 * sizes and estimate context window usage.
	 * @param annotations Optional annotations for the client. The client can use
	 * annotations to inform how objects are used or displayed.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ResourceLink( // @formatter:off
		@JsonProperty("name") String name,
		@JsonProperty("title") String title,
		@JsonProperty("uri") String uri,
		@JsonProperty("description") String description,
		@JsonProperty("mimeType") String mimeType,
		@JsonProperty("size") Long size,
		@JsonProperty("annotations") Annotations annotations,
		@JsonProperty("_meta") Map<String, Object> meta) implements Annotated, Content, ResourceContent { // @formatter:on

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link ResourceLink#ResourceLink(String, String, String, String, String, Long, Annotations)}
		 * instead.
		 */
		@Deprecated
		public ResourceLink(String name, String title, String uri, String description, String mimeType, Long size,
				Annotations annotations) {
			this(name, title, uri, description, mimeType, size, annotations, null);
		}

		/**
		 * @deprecated Only exists for backwards-compatibility purposes. Use
		 * {@link ResourceLink#ResourceLink(String, String, String, String, String, Long, Annotations)}
		 * instead.
		 */
		@Deprecated
		public ResourceLink(String name, String uri, String description, String mimeType, Long size,
				Annotations annotations) {
			this(name, null, uri, description, mimeType, size, annotations);
		}

		public static Builder builder() {
			return new Builder();
		}

		public static class Builder {

			private String name;

			private String title;

			private String uri;

			private String description;

			private String mimeType;

			private Annotations annotations;

			private Long size;

			private Map<String, Object> meta;

			public Builder name(String name) {
				this.name = name;
				return this;
			}

			public Builder title(String title) {
				this.title = title;
				return this;
			}

			public Builder uri(String uri) {
				this.uri = uri;
				return this;
			}

			public Builder description(String description) {
				this.description = description;
				return this;
			}

			public Builder mimeType(String mimeType) {
				this.mimeType = mimeType;
				return this;
			}

			public Builder annotations(Annotations annotations) {
				this.annotations = annotations;
				return this;
			}

			public Builder size(Long size) {
				this.size = size;
				return this;
			}

			public Builder meta(Map<String, Object> meta) {
				this.meta = meta;
				return this;
			}

			public ResourceLink build() {
				Assert.hasText(uri, "uri must not be empty");
				Assert.hasText(name, "name must not be empty");

				return new ResourceLink(name, title, uri, description, mimeType, size, annotations, meta);
			}

		}
	}

	// ---------------------------
	// Roots
	// ---------------------------
	/**
	 * Represents a root directory or file that the server can operate on.
	 *
	 * @param uri The URI identifying the root. This *must* start with file:// for now.
	 * This restriction may be relaxed in future versions of the protocol to allow other
	 * URI schemes.
	 * @param name An optional name for the root. This can be used to provide a
	 * human-readable identifier for the root, which may be useful for display purposes or
	 * for referencing the root in other parts of the application.
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record Root( // @formatter:off
		@JsonProperty("uri") String uri,
		@JsonProperty("name") String name,
		@JsonProperty("_meta") Map<String, Object> meta) { // @formatter:on

		public Root(String uri, String name) {
			this(uri, name, null);
		}
	}

	/**
	 * The client's response to a roots/list request from the server. This result contains
	 * an array of Root objects, each representing a root directory or file that the
	 * server can operate on.
	 *
	 * @param roots An array of Root objects, each representing a root directory or file
	 * that the server can operate on.
	 * @param nextCursor An optional cursor for pagination. If present, indicates there
	 * are more roots available. The client can use this cursor to request the next page
	 * of results by sending a roots/list request with the cursor parameter set to this
	 * @param meta See specification for notes on _meta usage
	 */
	@JsonInclude(JsonInclude.Include.NON_ABSENT)
	@JsonIgnoreProperties(ignoreUnknown = true)
	public record ListRootsResult( // @formatter:off
		@JsonProperty("roots") List<Root> roots,
		@JsonProperty("nextCursor") String nextCursor,
		@JsonProperty("_meta") Map<String, Object> meta) implements Result { // @formatter:on

		public ListRootsResult(List<Root> roots) {
			this(roots, null);
		}

		public ListRootsResult(List<Root> roots, String nextCursor) {
			this(roots, nextCursor, null);
		}
	}

}