@modelcontextprotocol/server-everything/dist/tools/get-annotated-message.js

MCP server that exercises all the features of the MCP protocol

import { z } from "zod";
import { MCP_TINY_IMAGE } from "./get-tiny-image.js";
import { TOOL_ICONS } from "../server/icons.js";
// Tool input schema
const GetAnnotatedMessageSchema = z.object({
    messageType: z
        .enum(["error", "success", "debug"])
        .describe("Type of message to demonstrate different annotation patterns"),
    includeImage: z
        .boolean()
        .default(false)
        .describe("Whether to include an example image"),
});
// Tool configuration
const name = "get-annotated-message";
const config = {
    title: "Get Annotated Message Tool",
    description: "Demonstrates how annotations can be used to provide metadata about content.",
    inputSchema: GetAnnotatedMessageSchema,
    icons: TOOL_ICONS,
    annotations: {
        readOnlyHint: true, // This tool only returns data, no side effects
        destructiveHint: false, // Does not delete or modify anything
        idempotentHint: true, // Same input always produces same output
        openWorldHint: false, // Does not interact with external systems
    },
};
/**
 * Registers the 'get-annotated-message' tool.
 *
 * The registered tool generates and sends messages with specific types, such as error,
 * success, or debug, carrying associated annotations like priority level and intended
 * audience.
 *
 * The response will have annotations and optionally contain an annotated image.
 *
 * @function
 * @param {McpServer} server - The McpServer instance where the tool will be registered.
 */
export const registerGetAnnotatedMessageTool = (server) => {
    server.registerTool(name, config, async (args) => {
        const { messageType, includeImage } = GetAnnotatedMessageSchema.parse(args);
        const content = [];
        // Main message with different priorities/audiences based on type
        if (messageType === "error") {
            content.push({
                type: "text",
                text: "Error: Operation failed",
                annotations: {
                    priority: 1.0, // Errors are highest priority
                    audience: ["user", "assistant"], // Both need to know about errors
                },
            });
        }
        else if (messageType === "success") {
            content.push({
                type: "text",
                text: "Operation completed successfully",
                annotations: {
                    priority: 0.7, // Success messages are important but not critical
                    audience: ["user"], // Success mainly for user consumption
                },
            });
            /* v8 ignore start -- the input schema's enum admits only error, success and debug, so the debug test is never false */
        }
        else if (messageType === "debug") {
            content.push({
                type: "text",
                text: "Debug: Cache hit ratio 0.95, latency 150ms",
                annotations: {
                    priority: 0.3, // Debug info is low priority
                    audience: ["assistant"], // Technical details for assistant
                },
            });
        }
        /* v8 ignore stop */
        // Optional image with its own annotations
        if (includeImage) {
            content.push({
                type: "image",
                data: MCP_TINY_IMAGE,
                mimeType: "image/png",
                annotations: {
                    priority: 0.5,
                    audience: ["user"], // Images primarily for user visualization
                },
            });
        }
        return { content };
    });
};