fix: raise and configure per-user gateway session capacity

src/config.ts

@@ -1,6 +1,9 @@
 import { readFileSync, statSync } from "node:fs";
 import { APPROVAL_BATCH_LIMIT } from "./approval-contract.js";
 
+export const DEFAULT_MCP_SESSION_MAX_PER_USER = 32;
+export const MCP_SESSION_MAX_TOTAL = 1000;
+
 export interface AppConfig {
   appMode?: "gateway";
   clientId: string;
@@ -11,6 +14,7 @@ export interface AppConfig {
   publicBaseUrl: string;
   bindHost?: string;
   port: number;
+  mcpSessionMaxPerUser?: number;
   requestTimeoutMs: number;
   officialLookbackDays: number;
   officialScanConcurrency: number;
@@ -167,6 +171,10 @@ export function loadConfig(env: NodeJS.ProcessEnv = process.env): AppConfig {
   if (!remoteAuthEnabled || !xftOpenApiEnabled) {
     throw new Error("gateway 模式必须启用 MCP 远程 OAuth 和薪福通正式 OpenAPI");
   }
+  const mcpSessionMaxPerUser = positiveInteger(env, "MCP_SESSION_MAX_PER_USER", DEFAULT_MCP_SESSION_MAX_PER_USER);
+  if (mcpSessionMaxPerUser > MCP_SESSION_MAX_TOTAL) {
+    throw new Error(`MCP_SESSION_MAX_PER_USER 不能超过全局会话上限 ${MCP_SESSION_MAX_TOTAL}`);
+  }
   return {
     appMode,
     clientId: dingTalkCredential(env, "DINGTALK_CLIENT_ID", "clientId"),
@@ -177,6 +185,7 @@ export function loadConfig(env: NodeJS.ProcessEnv = process.env): AppConfig {
     publicBaseUrl,
     bindHost,
     port,
+    mcpSessionMaxPerUser,
     requestTimeoutMs: positiveInteger(env, "DINGTALK_REQUEST_TIMEOUT_MS", 15_000),
     officialLookbackDays: Math.min(120, positiveInteger(env, "OFFICIAL_OA_LOOKBACK_DAYS", 120)),
     officialScanConcurrency: positiveInteger(env, "OFFICIAL_OA_SCAN_CONCURRENCY", 2),

src/mcp-http.ts

@@ -6,24 +6,24 @@ import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
 import { isInitializeRequest } from "@modelcontextprotocol/sdk/types.js";
 import type { AuthenticatedDingTalkUser } from "./xft.js";
 import { McpSessionLifecycle } from "./mcp-session-lifecycle.js";
+import { DEFAULT_MCP_SESSION_MAX_PER_USER, MCP_SESSION_MAX_TOTAL } from "./config.js";
 
 type TransportEntry =
   | { kind: "streamable"; transport: StreamableHTTPServerTransport; userId: string; lifecycle: McpSessionLifecycle }
   | { kind: "sse"; transport: SSEServerTransport; userId: string; lifecycle: McpSessionLifecycle };
 
-const MCP_SESSION_MAX_PER_USER = 8;
-const MCP_SESSION_MAX_TOTAL = 1000;
-
 interface McpTransportOptions {
   authenticate?: RequestHandler;
   // Production always resolves this from verified OAuth, never request parameters.
   requestUser: (req: Request) => AuthenticatedDingTalkUser;
   createServer: (user: AuthenticatedDingTalkUser, lifecycle: McpSessionLifecycle) => McpServer;
   now?: () => number;
+  maxSessionsPerUser?: number;
 }
 
 export function installMcpTransports(app: Express, options: McpTransportOptions) {
   const now = options.now ?? Date.now;
+  const maxSessionsPerUser = options.maxSessionsPerUser ?? DEFAULT_MCP_SESSION_MAX_PER_USER;
   const transports = new Map<string, TransportEntry>();
   let pendingTransportSessions = 0;
   const pendingTransportSessionsByUser = new Map<string, number>();
@@ -40,7 +40,7 @@ export function installMcpTransports(app: Express, options: McpTransportOptions)
   };
   const sessionCapacityAvailable = (userId: string) => transports.size + pendingTransportSessions < MCP_SESSION_MAX_TOTAL
     && [...transports.values()].filter((entry) => entry.userId === userId).length
-      + (pendingTransportSessionsByUser.get(userId) ?? 0) < MCP_SESSION_MAX_PER_USER;
+      + (pendingTransportSessionsByUser.get(userId) ?? 0) < maxSessionsPerUser;
   const reserveSession = (userId: string) => {
     pendingTransportSessions += 1;
     pendingTransportSessionsByUser.set(userId, (pendingTransportSessionsByUser.get(userId) ?? 0) + 1);

src/server.ts

@@ -462,6 +462,7 @@ export async function startHttpServer(config: AppConfig): Promise<void> {
 
   installMcpTransports(app, {
     authenticate: authMiddleware,
+    maxSessionsPerUser: config.mcpSessionMaxPerUser,
     requestUser: (req) => requestUser(config, oauth, req.auth),
     createServer: (user, lifecycle) => createApprovalMcpServer(
       config, service, xft, undefined, officialOaReturns, user,