@modelcontextprotocol/server-everything/dist/tools/toggle-subscriber-updates.js

MCP server that exercises all the features of the MCP protocol

// The `toggle-subscriber-updates` tool: starts or stops a timer that sends
// `notifications/resources/updated` for each resource the client subscribed
// to with `resources/subscribe`.
//
// 2025-era only, and deprecated: the 2026-07-28 revision removes
// `resources/subscribe` and unsolicited notifications, so the server factory
// registers this tool only for a 2025-era client. A 2026-07-28 client asks
// for updates in its `subscriptions/listen` filter, and
// `trigger-resource-update` sends one on demand. The timer belongs to the
// server instance serving this client, so no session map is needed (#4852).
import { beginSimulatedResourceUpdates } from "../resources/subscriptions.js";
import { TOOL_ICONS } from "../server/icons.js";
// Tool configuration
const name = "toggle-subscriber-updates";
const config = {
    title: "Toggle Subscriber Updates",
    description: "Toggles simulated resource subscription updates on or off. Deprecated: 2025-era clients only, " +
        "since protocol version 2026-07-28 removes resources/subscribe; use trigger-resource-update with a " +
        "subscriptions/listen stream instead.",
    inputSchema: {},
    icons: TOOL_ICONS,
    annotations: {
        readOnlyHint: false,
        destructiveHint: false,
        idempotentHint: false,
        openWorldHint: false,
    },
};
/**
 * Registers the `toggle-subscriber-updates` tool.
 *
 * The registered tool enables or disables the sending of periodic, simulated resource
 * update messages to the connected client for any subscriptions it has made.
 * Each call flips the state: it starts the updates when they are off and stops
 * them when they are on. The updates also stop when the connection ends.
 *
 * @param {McpServer} server - The McpServer instance where the tool will be registered.
 * @param {ServerContext} context - The instance's subscriptions and cleanup registry.
 */
export const registerToggleSubscriberUpdatesTool = (server, context) => {
    let stop;
    context.onCleanup(() => {
        stop?.();
        stop = undefined;
    });
    server.registerTool(name, config, async () => {
        let response;
        if (stop) {
            stop();
            stop = undefined;
            response = "Stopped simulated resource updates";
        }
        else {
            stop = beginSimulatedResourceUpdates(server, context.subscribed);
            response =
                "Started simulated resource updated notifications at a 5 second pace. Client will receive updates for any resources it is subscribed to.";
        }
        return {
            content: [{ type: "text", text: response }],
        };
    });
};