@modelcontextprotocol/server-everything/dist/server/context.js

MCP server that exercises all the features of the MCP protocol

// The per-instance context the server factory hands to the features that
// need more than the `McpServer` itself (#4852).
//
// Before the 2026-07-28 revision, features that kept state across calls
// (simulated logging, resource subscriptions, the roots cache, the URL
// elicitation error path) held it in module-level maps keyed by the
// transport's session id. The 2026-07-28 revision has no sessions, so that
// state now lives here, on the server instance the factory built: one per
// stdio connection, one per 2025-era Streamable HTTP session, and one per
// request on the 2026-07-28 HTTP path, where nothing survives between
// requests unless the server mints a handle for it (as the tasks store does).
//
// The context also carries the protocol era the instance serves, because a
// few features differ by era, and the publisher that announces list and
// resource changes, because where a change notification goes differs by
// transport: on stdio and on a 2025-era session the instance sends it
// itself, while on the 2026-07-28 HTTP path the instance lives for one
// request and the change goes out on the handler's subscription bus.
/**
 * A publisher that sends each change from `server` itself. On a 2025-era
 * connection the notification goes to the client unsolicited; on a
 * 2026-07-28 stdio connection `serveStdio` routes it onto the open
 * `subscriptions/listen` streams that asked for it.
 *
 * `resourceUpdated` is sent only for a URI `isSubscribed` accepts: a 2025-era
 * client subscribes per resource, and on 2026-07-28 the listen router does
 * the filtering, so the server passes `() => true` there.
 */
export function instancePublisher(server, isSubscribed) {
    const report = (error) => console.error("Change notification failed:", error);
    // The low-level sends return their promise; McpServer's own helpers start
    // the same send and drop it, so a failed one would go unhandled.
    const send = (notify) => {
        if (server.isConnected())
            notify().catch(report);
    };
    return {
        toolsChanged: () => send(() => server.server.sendToolListChanged()),
        promptsChanged: () => send(() => server.server.sendPromptListChanged()),
        resourcesChanged: () => send(() => server.server.sendResourceListChanged()),
        resourceUpdated: (uri) => {
            if (isSubscribed(uri)) {
                server.server.sendResourceUpdated({ uri }).catch(report);
            }
        },
    };
}